Notch Activation Research Articles

Abstract 5101: Inhibition of Notch reverses immunosuppression in basal-like breast cancer

Abstract Aberrant Notch activation is a defining feature of basal-like breast cancer (BLBC), which has poor prognosis compared to other breast cancer molecular subtypes. Despite the clinical success of immune checkpoint blockade (ICB) in many malignancies including melanoma and small cell lung cancer, ICB has failed to demonstrate similar response in BLBCs, where most cases are highly infiltrated by tumor-associated macrophages (TAMs). There is increasing evidence that Notch is decisive in regulating intercellular communication in the tumor immune microenvironment (TIME). This includes the recruitment of TAMs which contribute to an immunosuppressive TIME, illuminating the potential of Notch-inhibition as adjuvant immunotherapy in BLBC. To examine the immune phenotype and therapeutic response of BLBC to combined Notch-inhibition and ICB, we employed an in vivo tumorgraft model using murine basal-like mammary tumor 4T1 cells. Briefly, tumor cells were orthotopically injected into the mammary fat pads of BALB/c mice. Using a crossover design, mice were randomly allocated to treatment with either Notch inhibitor (γ-secretase inhibitor, LY411575), anti-PD1 (RMP1-14), or control treatment for 12-days (stage-1), followed by randomization to a second 12-day period (stage 2) with the same, or one of the other treatments. Results: Despite the low response rate of BLBC to ICB alone, Notch inhibition reduced TAMs and induced responsiveness to sequential ICB. This response was characterized by increased cytotoxic T lymphocytes (GrB+, CTL) infiltration of the primary tumor. Similar results were observed when Notch-regulated cytokines (IL-1β and CCL2), crucial to TAM recruitment, were inhibited. Moreover, a more impressive therapeutic effect of sequential treatment was observed in lung metastasis, whereby TAM depletion and increased CTL infiltration were accompanied with near-complete abolition of metastases. Mechanistically, tumor cell Notch signaling upregulates a group of circulating cytokines including IL-1β and CCL2, which prime the lung for metastases. Additionally, compared to primary tumor cells, PD ligand 1 is up-regulated in lung metastases, rendering them profoundly sensitive to sequential ICB treatment. These findings highlight the potential of sequential Notch inhibition and ICB as a novel immunotherapeutic strategy in BLBC. Citation Format: Qiang Shen, Kiichi Murakami, Pamela Ohashi, Michael Reedijk. Inhibition of Notch reverses immunosuppression in basal-like breast cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5101.

Abstract 2594: Alcohol drinking inhibits NOTCH-PAX9 signaling in esophageal squamous epithelial cells

Abstract Alcohol drinking has been established as a major risk factor for esophageal diseases, such as gastroesophageal reflux disease (GERD) and esophageal squamous cell carcinoma (ESCC). Certain mechanisms of alcohol-induced esophageal injury are supported by experimental data, whereas most are speculative or extrapolated from studies on cancers of other organ sites. Our previous study showed that ethanol exposure inhibited PAX9 expression in human esophageal squamous epithelial cells in vitro and in vivo, and promoted ESCC. In this study, we aimed to investigate the molecular pathways through which alcohol drinking suppresses PAX9 in esophageal squamous epithelial cells. Gene microarray, qRT-PCR, ChIP-PCR, Western blotting, and immunostaining were used to identify and validate inhibition of NOTCH-PAX9 signaling in human esophageal squamous epithelial cells and mouse esophagus after ethanol exposure. Human tissue samples were analyzed to further validate NOTCH inhibition by alcohol drinking. We first demonstrated the inhibition of NOTCH by ethanol exposure in vitro. NOTCH regulated PAX9 expression in esophageal squamous epithelial cells in vitro and in vivo. RBPJ and NOTCH intracellular domain (NICD1) ChIP-PCR confirmed Pax9 as a direct downstream target of NOTCH signaling in mouse esophagus. NOTCH inhibition by alcohol drinking was further validated in mouse esophagus and human tissue samples. In conclusion, ethanol exposure inhibited NOTCH signaling and thus suppressed PAX9 expression in esophageal squamous epithelial cells in vitro and in vivo. Our data support a novel mechanism of alcohol-induced esophageal injury through the inhibition of NOTCH-PAX9 signaling. As a result, chemical NOTCH activators may be used to prevent or treat alcohol-associated esophageal diseases such as GERD and ESCC. Citation Format: Zhaohui Xiong. Alcohol drinking inhibits NOTCH-PAX9 signaling in esophageal squamous epithelial cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2594.

Epsin1-mediated exosomal sorting of Dll4 modulates the tubular-macrophage crosstalk in diabetic nephropathy

Tubular epithelial cells (TECs) play critical roles in the development of diabetic nephropathy (DN), and can activate macrophages through the secretion of exosomes. However, the mechanism(s) of TEC-exosomes in macrophage activation under DN remains unknown. By mass spectrometry, 1,644 differentially expressed proteins, especially Dll4, were detected in the urine exosomes of DN patients compared with controls, which was confirmed by western blot assay. Elevated Epsin1 and Dll4/N1ICD expression was observed in kidney tissues in both DN patients and db/db mice and was positively associated with tubulointerstitial damage. Exosomes from high glucose (HG)-treated tubular cells (HK-2) with Epsin1 knockdown (KD) ameliorated macrophage activation, TNF-α, and IL-6 expression, and tubulointerstitial damage in C57BL/6 mice invivo. In an invitro study, enriched Dll4 was confirmed in HK-2 cells stimulated with HG, which was captured by THP-1 cells and promoted M1 macrophage activation. In addition, Epsin1 modulated the content of Dll4 in TEC-exosomes stimulated with HG. TEC-exosomes with Epsin1-KD significantly inhibited N1ICD activation and iNOS expression in THP-1 cells compared with incubation with HG alone. These findings suggested that Epsin1 could modulate tubular-macrophage crosstalk in DN by mediating exosomal sorting of Dll4 and Notch1 activation.

Abrogation of stemness in osteosarcoma by the mithramycin analog EC-8042 is mediated by its ability to inhibit NOTCH-1 signaling

Osteosarcomas are frequently associated to a poor prognosis and a modest response to current treatments. EC-8042 is a well-tolerated mithramycin analog that has demonstrated an efficient ability to eliminate tumor cells, including cancer stem cell subpopulations (CSC), in sarcomas. In transcriptomic and protein expression analyses, we identified NOTCH1 signaling as one of the main pro-stemness pathways repressed by EC-8042 in osteosarcomas. Overexpression of NOTCH-1 resulted in a reduced anti-tumor effect of EC-8042 in CSC-enriched 3D tumorspheres cultures. On the other hand, the depletion of the NOTCH-1 downstream target HES-1 was able to enhance the action of EC-8042 on CSCs. Moreover, HES1 depleted cells failed to recover after treatment withdrawal and showed reduced tumor growth potential in vivo. In contrast, mice xenografted with NOTCH1-overexpressing cells responded worse than parental cells to EC-8042. Finally, we found that active NOTCH1 levels in sarcoma patients was associated to advanced disease and lower survival. Overall, these data highlight the relevant role that NOTCH1 signaling plays in mediating stemness in osteosarcoma. Moreover, we demonstrate that EC-8042 is powerful inhibitor of NOTCH signaling and that the anti-CSC activity of this mithramycin analog highly rely on its ability to repress this pathway.

HES1-mediated down-regulation of miR-138 sustains NOTCH1 activation and promotes proliferation and invasion in renal cell carcinoma

BackgroundAlthough the aberrant activation of NOTCH1 pathway causes a malignant progression of renal cell carcinoma (RCC), the precise molecular mechanisms behind the potential action of pro-oncogenic NOTCH1/HES1 axis remain elusive. Here, we examined the role of tumor suppressive miR-138–2 in the regulation of NOTCH1-HES1-mediated promotion of RCC.MethodsThis study employed bioinformatics, xenotransplant mouse models, ChIP assay, luciferase reporter assay, functional experiments, real-time PCR and Western blot analysis to explore the mechanisms of miR-138–2 in the regulation of NOTCH1-HES1-mediated promotion of RCC, and further explored miR-138–2-containing combination treatment strategies.ResultsThere existed a positive correlation between down-regulation of miR-138 and the aberrant augmentation of NOTCH1/HES1 regulatory axis. Mechanistically, HES1 directly bound to miR-138–2 promoter region and thereby attenuated the transcription of miR-138-5p as well as miR-138–2-3p. Further analysis revealed that miR-138-5p as well as miR-138–2-3p synergistically impairs pro-oncogenic NOTCH1 pathway through the direct targeting of APH1A, MAML1 and NOTCH1.ConclusionsCollectively, our current study strongly suggests that miR-138–2 acts as a novel epigenetic regulator of pro-oncogenic NOTCH1 pathway, and that the potential feedback regulatory loop composed of HES1, miR-138–2 and NOTCH1 contributes to the malignant development of RCC. From the clinical point of view, this feedback regulatory loop might be a promising therapeutic target to treat the patients with RCC.

Notch-RBPJ Pathway for the Differentiation of Bone Marrow Mesenchymal Stem Cells in Femoral Head Necrosis

Femoral head necrosis (FHN) is a common leg disease in broilers, resulting in economic losses in the poultry industry. The occurrence of FHN is closely related to the decrease in the number of bone marrow mesenchymal stem cells (BMSCs) and the change in differentiation direction. This study aimed to investigate the function of differentiation of BMSCs in the development of FHN. We isolated and cultured BMSCs from spontaneous FHN-affected broilers and normal broilers, assessed the ability of BMSCs into three lineages by multiple staining methods, and found that BMSCs isolated from FHN-affected broilers demonstrated enhanced lipogenic differentiation, activated Notch-RBPJ signaling pathway, and diminished osteogenic and chondrogenic differentiation. The treatment of BMSCs with methylprednisolone (MP) revealed a significant decrease in the expressions of Runx2, BMP2, Col2a1 and Aggrecan, while the expressions of p-Notch1/Notch1, Notch2 and RBPJ were increased significantly. Jagged-1 (JAG-1, Notch activator)/DAPT (γ-secretase inhibitor) could promote/inhibit the osteogenic or chondrogenic ability of MP-treated BMSCs, respectively, whereas the differentiation ability of BMSCs was restored after transfection with si-RBPJ. The above results suggest that the Notch-RBPJ pathway plays important role in FHN progression by modulating the osteogenic and chondrogenic differentiation of BMSCs.

Bioprinted Notch ligand to function as stem cell niche improves muscle regeneration in dystrophic muscle.

299In Duchenne muscular dystrophy, dystrophic muscle phenotypes are closely associated with the exhaustion of muscle stem cells. Transplantation of muscle stem cells has been widely studied for improving muscle regeneration, but poor cell survival and self-renewal, rapid loss of stemness, and limited dispersion of grafted cells following transplantation have collectively hindered the overall success of this strategy. Optimized mechanisms for maintaining and improving stem cell function are naturally present in the microenvironment of the stem cell niche in healthy muscles. Therefore, one logical strategy toward improving stem cell function and efficiency of stem cell transplantation in diseased muscles would be the establishment of a microenvironment mimicking some key aspects of healthy native stem cell niches. Here, we applied inkjet-based bioprinting technology to engineer a mimicked artificial stem cell niche in dystrophic muscle, comprising stem cell niche regulating factors (Notch activator DLL1) bioprinted onto 3D DermaMatrix construct. The recombinant DLL1 protein, DLL1 (mouse): Fc (human) (rec), was applied here as the Notch activator. Bioprinted DermaMatrix construct was seeded with muscle stem cells in vitro, and increased stem cell maintenance and repressed myogenic differentiation process was observed. DLL1 bioprinted DermaMatrix construct was then engrafted into dystrophic muscle of mdx/scid mice, and the improved cell engraftment and progression of muscle regeneration was observed 10 days after engraftment. Our results demonstrated that bioprinting of Notch activator within 3D construct can be applied to serve as muscle stem cell niche and improve the efficacy of muscle stem cell transplantation in diseased muscle.

VEGF dose controls the coupling of angiogenesis and osteogenesis in engineered bone

Vascular endothelial growth factor-A (VEGF) physiologically regulates both angiogenesis and osteogenesis, but its application in bone tissue engineering led to contradictory outcomes. A poorly understood aspect is how VEGF dose impacts the coordination between these two processes. Taking advantage of a unique and highly tunable platform, here we dissected the effects of VEGF dose over a 1,000-fold range in the context of tissue-engineered osteogenic grafts. We found that osteo-angiogenic coupling is exquisitely dependent on VEGF dose and that only a tightly defined dose range could stimulate both vascular invasion and osteogenic commitment of progenitors, with significant improvement in bone formation. Further, VEGF dose regulated Notch1 activation and the induction of a specific pro-osteogenic endothelial phenotype, independently of the promotion of vascular invasion. Therefore, in a therapeutic perspective, fine-tuning of VEGF dose in the signaling microenvironment is key to ensure physiological coupling of accelerated vascular invasion and improved bone formation.

Loss of ATP2C1 function promotes trafficking and degradation of NOTCH1: Implications for Hailey-Hailey disease.

Hailey-Hailey disease (HHD) is a rare autosomal dominantly inherited disorder caused by mutations in the ATP2C1 gene that encodes an adenosine triphosphate (ATP)-powered calcium channel pump. HHD is characterized by impaired epidermal cell-to-cell adhesion and defective keratinocyte growth/differentiation. The mechanism by which mutant ATP2C1 causes HHD is unknown and current treatments for affected individuals do not address the underlying defects and are ineffective. Notch signalling is a direct determinant of keratinocyte growth and differentiation. We found that loss of ATP2C1 leads to impaired Notch1 signalling, thus deregulation of the Notch signalling response is therefore likely to contribute to HHD manifestation. NOTCH1 is a transmembrane receptor and upon ligand binding, theintracellular domain (NICD) translocates to the nucleus activating its target genes. In the context of HHD, we found that loss of ATP2C1 function promotes upregulation of the active NOTCH1 protein (NICD-Val1744). Here, deeply exploring this aspect, we observed that NOTCH1 activation is not associated with the transcriptional enhancement of its targets. Moreover, in agreement with these results, we found a cytoplasmic localization of NICD-Val1744. We have also observed that ATP2C1-loss is associated with the degradation of NICD-Val1744 through the lysosomal/proteasome pathway. These results show that ATP2C1-loss could promote a mechanism by which NOTCH1 is endocytosed and degraded by the cell membrane. The deregulation of this phenomenon, finely regulated in physiological conditions, could in HHD lead to the deregulation of NOTCH1 with alteration of skin homeostasis and disease manifestation.

A novel chemical attack on Notch-mediated transcription by targeting the NACK ATPase

Notch activation complex kinase (NACK) is a component of the Notch transcriptional machinery critical for the Notch-mediated tumorigenesis. However, the mechanism through which NACK regulates Notch-mediated transcription is not well understood. Here, we demonstrate that NACK binds and hydrolyzes ATP and that only ATP-bound NACK can bind to the Notch ternary complex (NTC). Considering this, we sought to identify inhibitors of this ATP-dependent function and, using computational pipelines, discovered the first small-molecule inhibitor of NACK, Z271-0326, that directly blocks the activity of Notch-mediated transcription and shows potent antineoplastic activity in PDX mouse models. In conclusion, we have discovered the first inhibitor that holds promise for the efficacious treatment of Notch-driven cancers by blocking the Notch activity downstream of the NTC.

Loss of ndrg2 Function Is Involved in Notch Activation in Neuromast Hair Cell Regeneration in Zebrafish.

The regeneration of hair cells in zebrafish is a complex process involving the precise regulation of multiple signaling pathways, but this complicated regulatory network is not fully understood. Current research has primarily focused on finding molecules and pathways that can regulate hair cell regeneration and restore hair cell functions. Here, we show the role of N-Myc downstream regulated gene 2 (ndrg2) in zebrafish hair cell regeneration. We first found that ndrg2 was dynamically expressed in neuromasts of the developing zebrafish, and this expression was increased after neomycin-induced hair cell damage. Then, ndrg2 loss-of-function larvae showed reduced numbers of regenerated hair cells but increased numbers of supporting cells after neomycin exposure. By in situ hybridization, we further observed that ndrg2 loss of function resulted in the activation of Notch signaling and downregulation of atoh1a during hair cell regeneration in vivo. Additionally, blocking Notch signaling rescued the number of regenerated hair cells in ndrg2-deficient larvae. Together, this study provides evidence for the role of ndrg2 in regulating hair cell regeneration in zebrafish neuromasts.

LncRNA BREA2 promotes metastasis by disrupting the WWP2-mediated ubiquitination of Notch1

Notch has been implicated in human cancers and is a putative therapeutic target. However, the regulation of Notch activation in the nucleus remains largely uncharacterized. Therefore, characterizing the detailed mechanisms governing Notch degradation will identify attractive strategies for treating Notch-activated cancers. Here, we report that the long noncoding RNA (lncRNA) BREA2 drives breast cancer metastasis by stabilizing the Notch1 intracellular domain (NICD1). Moreover, we reveal WW domain containing E3 ubiquitin protein ligase 2 (WWP2) as an E3 ligase for NICD1 at K1821 and a suppressor of breast cancer metastasis. Mechanistically, BREA2 impairs WWP2-NICD1 complex formation and in turn stabilizes NICD1, leading to Notch signaling activation and lung metastasis. BREA2 loss sensitizes breast cancer cells to inhibition of Notch signaling and suppresses the growth of breast cancer patient-derived xenograft tumors, highlighting its therapeutic potential in breast cancer. Taken together, these results reveal the lncRNA BREA2 as a putative regulator of Notch signaling and an oncogenic player driving breast cancer metastasis.

Aberrant fucosylation sustains the NOTCH and EGFR/NF-κB pathways and has a prognostic value in human intrahepatic cholangiocarcinoma.

Intrahepatic cholangiocarcinoma (iCCA) is a lethal malignancy, with increasing incidence worldwide and limited therapeutic options. Aberrant protein glycosylation is a hallmark of cancer. Here, we thoroughly investigated the possible involvement of fucosylation in cholangiocarcinogenesis. We discovered that the levels of global fucosylation and members of the fucosylation pathway are ubiquitously upregulated in human iCCA tissues compared to nontumorous surrounding livers and normal biliary cells. In addition, total fucosylation levels correlate with poor patients' prognosis. Furthermore, fucosylation inhibition following 6-alkynylfucose (6AF) administration triggered a dose-dependent decrease in the proliferation and migration of iCCA cell lines. Notably, adding fucose to the cell medium annulled these effects. At the molecular level, 6AF administration or small interfering RNA-mediated silencing of GDP-L-fucose synthetase (FX) and the GDP-fucose transmembrane transporter (SLC35C1), both pivotal players of cellular fucosylation, decreased NOTCH activity, NOTCH1/Jagged1 interaction, NOTCH receptors, and related target genes in iCCA cell lines. In the same cells, EGFR, nuclear factor kappa-light-chain-enhancer of activated B cells p65, and Bcl-xL protein levels diminished, whereas IκBα (a critical cellular NF-κB inhibitor) increased after FX/SLC35C1 knockdown or 6AF administration. In the chick chorioallantoic membrane assay, 6AF treatment profoundly suppresses the growth of iCCA cells. Elevated global fucosylation characterizes human iCCA, contributing to cell growth and migration through the upregulation of the NOTCH and EGFR/NF-κB pathways. Thus, aberrant fucosylation is a novel pathogenetic player and a potential therapeutic target for human iCCA.

Notch signaling in development and homeostasis.

Notch signaling is a highly conserved signaling pathway that coordinates cellular differentiation during the development and homeostasis in numerous organs and tissues across metazoans. Activation of Notch signaling relies on direct contact between neighboring cells and mechanical pulling of the Notch receptors by the Notch ligands. Notch signaling is commonly used in developmental processes to coordinate the differentiation into distinct cell fates of neighboring cells. In this Development at a Glance article, we describe the current understanding of the Notch pathway activation and the different regulatory levels that control the pathway. We then describe several developmental processes where Notch is crucial for coordinating differentiation. These examples include processes that are largely based on lateral inhibition mechanisms giving rise to alternating patterns (e.g. SOP selection, hair cell in the inner ear and neural stem cell maintenance), as well as processes where Notch activity is oscillatory (e.g. somitogenesis and neurogenesis in mammals).

Role of SOCS and VHL Proteins in Neuronal Differentiation and Development.

The basic helix-loop-helix factors play a central role in neuronal differentiation and nervous system development, which involve the Notch and signal transducer and activator of transcription (STAT)/small mother against decapentaplegic signaling pathways. Neural stem cells differentiate into three nervous system lineages, and the suppressor of cytokine signaling (SOCS) and von Hippel-Lindau (VHL) proteins are involved in this neuronal differentiation. The SOCS and VHL proteins both contain homologous structures comprising the BC-box motif. SOCSs recruit Elongin C, Elongin B, Cullin5(Cul5), and Rbx2, whereas VHL recruits Elongin C, Elongin B, Cul2, and Rbx1. SOCSs form SBC-Cul5/E3 complexes, and VHL forms a VBC-Cul2/E3 complex. These complexes degrade the target protein and suppress its downstream transduction pathway by acting as E3 ligases via the ubiquitin-proteasome system. The Janus kinase (JAK) is the main target protein of the E3 ligase SBC-Cul5, whereas hypoxia-inducible factor is the primary target protein of the E3 ligase VBC-Cul2; nonetheless, VBC-Cul2 also targets the JAK. SOCSs not only act on the ubiquitin-proteasome system but also act directly on JAKs to suppress the Janus kinase-signal transduction and activator of transcription (JAK-STAT) pathway. Both SOCS and VHL are expressed in the nervous system, predominantly in brain neurons in the embryonic stage. Both SOCS and VHL induce neuronal differentiation. SOCS is involved in differentiation into neurons, whereas VHL is involved in differentiation into neurons and oligodendrocytes; both proteins promote neurite outgrowth. It has also been suggested that the inactivation of these proteins may lead to the development of nervous system malignancies and that these proteins may function as tumor suppressors. The mechanism of action of SOCS and VHL involved in neuronal differentiation and nervous system development is thought to be mediated through the inhibition of downstream signaling pathways, JAK-STAT, and hypoxia-inducible factor-vascular endothelial growth factor pathways. In addition, because SOCS and VHL promote nerve regeneration, they are expected to be applied in neuronal regenerative medicine for traumatic brain injury and stroke.

Germline protein, Cup, non-cell autonomously limits migratory cell fate in Drosophila oogenesis.

Specification of migratory cell fate from a stationary population is complex and indispensable both for metazoan development as well for the progression of the pathological condition like tumor metastasis. Though this cell fate transformation is widely prevalent, the molecular understanding of this phenomenon remains largely elusive. We have employed the model of border cells (BC) in Drosophila oogenesis and identified germline activity of an RNA binding protein, Cup that limits acquisition of migratory cell fate from the neighbouring follicle epithelial cells. As activation of JAK-STAT in the follicle cells is critical for BC specification, our data suggest that Cup, non-cell autonomously restricts the domain of JAK-STAT by activating Notch in the follicle cells. Employing genetics and Delta endocytosis assay, we demonstrate that Cup regulates Delta recycling in the nurse cells through Rab11GTPase thus facilitating Notch activation in the adjacent follicle cells. Since Notch and JAK-STAT are antagonistic, we propose that germline Cup functions through Notch and JAK-STAT to modulate BC fate specification from their static epithelial progenitors.

Unbalanced vibration control of active magnetic bearing using an active disturbance rejection notch decoupling technique

Aiming at the position coupling, gyroscopic effect, and synchronized vibration caused by the unbalance mass in the magnetic bearing rotor, a linear active disturbance rejection notch decoupling control method is proposed. Firstly, a model with coupling and unbalanced vibration of the system was established. The terms of position coupling, gyroscopic effect, and unbalanced vibration in the system are estimated by Extended State Observer and the estimator is treated as the system disturbance to be compensated, then the radially existing coupled and unbalanced vibration systems are decoupled into four independent second-order series-integrated subsystems. The nonlinear state error feedback control law is designed to implement the decoupling control of each subsystem. For the problem of unbalanced vibration of the rotor after decoupling, the suppression method of the dynamic unbalanced force of the same frequency notch filter is designed, and then the closed-loop feedback structure of the new method is deduced, and its frequency characteristics are analyzed. Then the rules and principles of controller parameter selection are summarized using Bode diagram. The simulation results show that the designed linear active disturbance rejection notch decoupling controller not only achieves the decoupling control of the respective degrees of the magnetic bearing rotor but also suppresses the unbalanced vibration of the rotor. At the same time, it solves the influence of the gyroscopic effect on the control under the high-speed running of the magnetic bearing rotor.

Notch-mediated hepatocyte MCP-1 secretion causes liver fibrosis.

Patients with nonalcoholic steatohepatitis (NASH) have increased expression of liver monocyte chemoattractant protein-1 (MCP-1), but its cellular source and contribution to various aspects of NASH pathophysiology remain debated. We demonstrated increased liver CCL2 (which encodes MCP-1) expression in patients with NASH, and commensurately, a 100-fold increase in hepatocyte Ccl2 expression in a mouse model of NASH, accompanied by increased liver monocyte-derived macrophage (MoMF) infiltrate and liver fibrosis. To test repercussions of increased hepatocyte-derived MCP-1, we generated hepatocyte-specific Ccl2-knockout mice, which showed reduced liver MoMF infiltrate as well as decreased liver fibrosis. Forced hepatocyte MCP-1 expression provoked the opposite phenotype in chow-fed wild-type mice. Consistent with increased hepatocyte Notch signaling in NASH, we observed a close correlation between markers of Notch activation and CCL2 expression in patients with NASH. We found that an evolutionarily conserved Notch/recombination signal binding protein for immunoglobulin kappa J region binding site in the Ccl2 promoter mediated transactivation of the Ccl2 promoter in NASH diet-fed mice. Increased liver MoMF infiltrate and liver fibrosis seen in opposite gain-of-function mice was ameliorated with concomitant hepatocyte Ccl2 knockout or CCR2 inhibitor treatment. Hepatocyte Notch activation prompts MCP-1-dependent increase in liver MoMF infiltration and fibrosis.

Active Notch Filters of the Fourth Order with an Adjustable Delay Band and Uneven Amplitude–Frequency Response

Potential structural schemes of notch filters (NFs) of the fourth order are considered. Equations for the coefficients of their transfer functions are given. A graphical interpretation of the parameters of the amplitude–frequency response (AFR) of the proposed NF is presented. An implementation example of the fourth-order NF is studied and simulated in the MicroCap 12 environment, confirming the possibility of independent adjustment of AFR unevenness in the passband and in the stopband.

Active Notch RC-Filters of the Fourth Order with an Adjustable Delay Band and Uneven Amplitude–Frequency Response

Active Notch RC-Filters of the Fourth Order with an Adjustable Delay Band and Uneven Amplitude–Frequency Response