N6-Methyladenosine-mediated phase separation suppresses NOTCH1 expression and promotes mitochondrial fission in diabetic cardiac fibrosis.

BACKGROUND: N6-methyladenosine (m6A) modification of messenger RNA (mRNA) is crucial for liquid-liquid phase separation in mammals. Increasing evidence indicates that liquid-liquid phase separation in proteins and RNAs affects diabetic cardiomyopathy. However, the molecular mechanism by which m6A-mediated phase separation regulates diabetic cardiac fibrosis remains elusive. METHODS: Leptin receptor-deficient mice (db/db), cardiac fibroblast-specific Notch1 conditional knockout (POSTN-Cre × Notch1flox/flox) mice, and Cre mice were used to induce diabetic cardiac fibrosis. Adeno-associated virus 9 carrying cardiac fibroblast-specific periostin (Postn) promoter-driven small hairpin RNA targeting Alkbh5, Ythdf2, or Notch1, and the phase separation inhibitor 1,6-hexanediol were administered to investigate their roles in diabetic cardiac fibrosis. Histological and biochemical analyses were performed to determine how Alkbh5 and Ythdf2 regulate Notch1 expression in diabetic cardiac fibrosis. NOTCH1 was reconstituted in ALKBH5- and YTHDF2-deficient cardiac fibroblasts and mouse hearts to study its effects on mitochondrial fission and diabetic cardiac fibrosis. Heart tissue samples from patients with diabetic cardiomyopathy were used to validate our findings. RESULTS: In mice with diabetic cardiac fibrosis, decreased Notch1 expression was accompanied by high m6A mRNA levels and mitochondrial fission. Fibroblast-specific deletion of Notch1 enhanced mitochondrial fission and cardiac fibroblast proliferation and induced diabetic cardiac fibrosis in mice. Notch1 downregulation was associated with Alkbh5-mediated m6A demethylation in the 3'UTR of Notch1 mRNA and elevated m6A mRNA levels. These elevated m6A levels in Notch1 mRNA markedly enhanced YTHDF2 phase separation, increased the recognition of m6A residues in Notch1 mRNA by YTHDF2, and induced Notch1 degradation. Conversely, epitranscriptomic downregulation rescues Notch1 expression, resulting in the opposite effects. Human heart tissues from patients with diabetic cardiomyopathy were used to validate the findings in mice with diabetic cardiac fibrosis. CONCLUSIONS: We identified a novel epitranscriptomic mechanism by which m6A-mediated phase separation suppresses Notch1 expression, thereby promoting mitochondrial fission in diabetic cardiac fibrosis. Our findings provide new insights for the development of novel treatment approaches for patients with diabetic cardiac fibrosis.

MicroRNA-124a promoted the differentiation of bone marrow mesenchymal stem cells into neurons through Notch signal pathway.

This study investigated the possible mechanisms of microRNA-124a on the differentiation of bone marrow mesenchymal stem cells (BMSCs) and its underlying mechanism. ß-Thiol ethanol induced Notch1 mRNA expression, microRNA-124a inhibitor reduced the effects of ß-thiol ethanol on Notch1 mRNA expression in BMSCs. Baicalin induced Hes1 mRNA expression, and microRNA-124a inhibitor reduced the effects of baicalin on Hes1 mRNA expression in BMSCs. Si-Notch1 suppressed Hes1 mRNA expression in BMSCs. Baicalin increased the effects of Notch1 on Hes1 mRNA expression in BMSCs. Si-Notch1 increased cell growth of BMSCs. Baicalin reduced the effects of si-Notch1 on cell growth and the differentiation of BMSCs. We demonstrated that microRNA-124a promoted the differentiation of BMSCs into neurons through Notch/Hes1 signal pathway.

Didymin ameliorates ulcerative colitis-associated secondary liver damage by facilitating Notch1 degradation.

BACKGROUND: Didymin is a dietary flavonoid originally discovered by our group as a potent anti-ulcerative colitis (UC) agent. However, whether didymin plays a protective role in UC-associated inflammatory liver injury is still unclear. PURPOSE: This study aimed to evaluate the therapeutic potential of didymin on UC-associated inflammatory liver injury and explore the underlying mechanism. STUDY DESIGN AND METHODS: Colitis model was established in C57BL/6 mice by exposure to DSS, and didymin was administrated intragastrically for consecutive 10 days. The inflammatory liver injury was assessed by levels of alanine aminotransferase (ALT) and aspartate transaminase (AST) in serum and histopathological damage in the liver. In vitro Kupffer cells and RAW264.7 cells challenged with lipopolysaccharides (LPS) were used to explore the modulatory activity of didymin on pro-inflammatory cytokines secretion and Notch1 signaling pathway activation. RESULTS: Didymin significantly mitigated liver coefficiency, ALT and AST levels in serum, and the hepatic histopathological damage caused by DSS-induced acute and chronic colitis. The mRNA expressions of pro-inflammatory factors including Tnf, Il1, and Il6 in liver tissues, Kupffer cells, and RAW264.7 cells stimulated by the influx of LPS was significantly deprived after didymin treatment. Mechanistically, didymin obstructed the protein expression, nuclear translocation of notch intracellular domain 1 (Notch1-ICD) and mRNA expression of hairy and enhancer of split 1 (Hes1). Further, the inhibitory mechanism of the Notch1-Hes1 pathway was dependent on c-Cbl-mediated Notch1-ICD lysosomal degradation. CONCLUSION: Our study verified for the first time that didymin could prevent UC-associated diseases, such as inflammatory liver injury, and the mechanism was related to facilitating Notch1 lysosomal degradation rather than proteasome degradation via promoting protein expression of c-Cbl in macrophages. Our findings that the inhibition of Notch1 signaling transduction helps to alleviate UC-associated liver injury provides possible therapeutics for the treatment of colitis and also furnishes a research paradigm for the study of flavonoids with similar structures.

Notch1 Phase Separation Coupled Percolation facilitates target gene expression and enhancer looping.

The Notch receptor is a pleiotropic signaling protein that translates intercellular ligand interactions into changes in gene expression via the nuclear localization of the Notch intracellular Domain (NICD). Using a combination of immunohistochemistry, RNA in situ, Optogenetics and super-resolution live imaging of transcription in human cells, we show that the N1ICD can form condensates that positively facilitate Notch target gene expression. We determined that N1ICD undergoes Phase Separation Coupled Percolation (PSCP) into transcriptional condensates, which recruit, enrich, and encapsulate a broad set of core transcriptional proteins. We show that the capacity for condensation is due to the intrinsically disordered transcriptional activation domain of the N1ICD. In addition, the formation of such transcriptional condensates acts to promote Notch-mediated super enhancer-looping and concomitant activation of the MYC protooncogene expression. Overall, we introduce a novel mechanism of Notch1 activity in which discrete changes in nuclear N1ICD abundance are translated into the assembly of transcriptional condensates that facilitate gene expression by enriching essential transcriptional machineries at target genomic loci.

Effect of miR-184 on Multiple Myeloma by Targeting Notch1.

OBJECTIVE: Multiple myeloma (MM) is caused by abnormal cloning of plasma cells. miR-184 is abnormally expressed in several types of tumors, but its expression and role in MM have not been reported. METHODS: The bone marrow samples of healthy controls and MM patients were collected, and plasma cells were sorted. The multiple myeloma cell line OPM-2 was cultured and assigned into miR-NC+siRNA-NC group, miR-184 inhibitor+siRNA-NC group, and miR-184 inhibitor+siRNA-Notch1 group. Cell proliferation was assessed by MTT assay. Clone formation was evaluated by colony formation assay. Cell apoptosis activity was tested with flow cytometry. Notch1 and cleaved caspase3 protein expressions were detected. RESULTS: MiR-184 expression was increased in myeloma plasma cells (P<0.05). Transfection of miR-184 inhibitor can downregulate miR-184 expression, increase the levels of Notch1 and cleaved caspase3, inhibit OPM-2 cell proliferation, restrain colony formation, enhance caspase3 activity, and suppress tumor cell invasion (P<0.05). However, administration of siRNA-Notch1 retarded the effect of miR-184 inhibitor by decreasing the expressions of Notch1 and cleaved caspase3, enhancing colony formation and tumor cell invasion, as well as inhibiting caspase3 activity and cell proliferation. CONCLUSION: Our data indicated that miR-184 expression is increased in myeloma plasma cells. Down-regulation of miR-184 promotes MM cell apoptosis and inhibits proliferation and colony formation by regulating Notch1 expression.

Protective Effects of Gastrodin Against Gentamicin-Induced Vestibular Damage by the Notch Signaling Pathway.

PURPOSE: Gentamicin is a broad-spectrum antibiotic commonly used in clinical practice. However, the drug causes side effects of ototoxicity, leading to disruption in balance functionality. This study investigated the effect of gastrodin, a prominent compound present in Gastrodia, and the underlying mechanism on the development of gentamicin-induced vestibular dysfunction. METHODS: Wild-type C57BL/6 mice were randomly assigned to three groups: control, gentamicin, and gentamicin + gastrodin groups. The extent of gentamicin-induced vestibular impairment was assessed through a series of tests including the swimming test, contact righting reflex test, and air-righting reflex. Alterations in vestibular hair cells were monitored through immunofluorescence assay, and cellular apoptosis was observed using TUNEL staining. The mRNA and protein expression of Notch1, Jagged1, and Hes1 was quantified through qRT-PCR, immunofluorescence, and western blot analyses. RESULTS: Gentamicin treatment led to pronounced deficits in vestibular function and otolith organ hair cells in mice. Nevertheless, pretreatment with gastrodin significantly alleviated these impairments. Additionally, the Notch signaling pathway was activated by gentamicin in the utricle, contributing to a notable increase in the expression levels of apoptosis-associated proteins. By contrast, gastrodin treatment effectively suppressed the Notch signaling pathway, thereby mitigating the occurrence of apoptosis. CONCLUSION: Collectively, these findings underscore the crucial role of gastrodin in safeguarding against gentamicin-induced vestibular dysfunction through the modulation of the Notch signaling pathway. This study suggests the potential of gastrodin as a promising therapeutic agent for preventing vestibular injuries.

Notch signaling mediated repressive effects of resveratrol in inducing caspasedependent apoptosis in MCF-7 breast cancer cells.

Resveratrol, a potent anticancer bioactive compound, has been shown to trigger apoptosis in numerous cancer cells. Although Notch signaling promotes breast cancer apoptosis, it is unclear whether resveratrol induces apoptosis in MCF-7 cells via influencing the Notch pathway. This study aimed to evaluate the effect of resveratrol on modulating Notch signaling targets and provide critical information for employing resveratrol in breast cancer therapy. Thus, in this study, we have deciphered the effect of resveratrol against three potent genes (Notch1, Jagged1, and DLL4) of the notch signaling pathway. For mechanistic studies, in silico, and in vitro analysis was executed to investigate the apoptotic-inducing potential of resveratrol against three selected oncogenes involved in the progression of breast cancer. Docking analysis revealed the inhibitory potential of resveratrol against all three selected targets of the Notch pathway (Notch1: -5.0; Jagged-1: -5.9; DLL4: -5.8). In vitro, findings further displayed a significant reduction in cell viability in resveratrol-treated MCF-7 cancer cells, which were concomitantly related to the downregulation of Notch-1, Jagged-1, and DLL4. Moreover, the antiproliferative efficacy of resveratrol was correlated with apoptosis and modulation in the expression of Bax, Bcl-2, cyclin D1, CDK4, p21, and caspase-3 activation. Taken together, these experimental findings suggested that apoptotic inducing potential of resveratrol was mediated through a novel mechanism involving suppression of the Notch signaling pathway.

Prognostic Impact of Notch1 Intracellular Domain, P63, and c-MYC in Lacrimal Gland Adenoid Cystic Carcinoma.

Purpose: We assessed whether NICD1 expression, c-MYC expression, and P63 expression by immunohistochemistry (IHC) correlate with prognosis and high-risk clinicopathological features in lacrimal gland adenoid cystic carcinoma (ACC). Methods: Records of patients with lacrimal gland ACC who underwent surgery between 1998 to 2018 were reviewed. Clinicopathologic and treatment data were collected. Tumor tissues were subjected to light microscopy and IHC. Results: Of 43 patients treated during the study period, 21 had archived tumor tissue available and were included. The median age at diagnosis was 47 years, and 13 patients (62%) were male. Thirteen patients (62%) had T2 disease, and none had nodal or distant metastasis at diagnosis. Tumors were positive for NICD1 expression in eight cases (38%), c-MYC expression in eight (38%), and P63 expression in 11 (52%). Positive NICD1 expression was associated with predominantly solid (vs. cribriform/tubular) pattern (P < 0.001), treatment with orbital exenteration (vs. eye-sparing surgery) (P = 0.008), local recurrence (P = 0.047), and death (P = 0.012). Negative P63 expression was associated with predominantly solid pattern (P = 0.001), local recurrence (P = 0.012), distant metastasis (P = 0.001), and death (P = 0.035). A higher percentage of tumor cells staining for c-MYC was associated with presence of perineural invasion (P = 0.036). Positive NICD1 expression was associated with worse disease-free survival (hazard ratio, 6.27; 95% CI, 1.29-30.46), whereas positive P63 expression was associated with better disease-free survival (hazard ratio, 0.03; 95% CI, 0.0002-0.26). Conclusions: IHC for NICD1 and P63 should be considered in lacrimal gland ACC because of their prognostic value and potential as treatment targets.

Cannabinoid combination targets NOTCH1-mutated T-cell acute lymphoblastic leukemia through the integrated stress response pathway.

In T-cell acute lymphoblastic leukemia (T-ALL), more than 50% of cases display autoactivation of Notch1 signaling, leading to oncogenic transformation. We have previously identified a specific chemovar of Cannabis that induces apoptosis by preventing Notch1 maturation in leukemia cells. Here, we isolated three cannabinoids from this chemovar that synergistically mimic the effects of the whole extract. Two were previously known, cannabidiol (CBD) and cannabidivarin (CBDV), whereas the third cannabinoid, which we termed 331-18A, was identified and fully characterized in this study. We demonstrated that these cannabinoids act through cannabinoid receptor type 2 and TRPV1 to activate the integrated stress response pathway by depleting intracellular Ca2+. This is followed by increased mRNA and protein expression of ATF4, CHOP, and CHAC1, which is hindered by inhibiting the upstream initiation factor eIF2α. The increased abundance of CHAC1 prevents Notch1 maturation, thereby reducing the levels of the active Notch1 intracellular domain, and consequently decreasing cell viability and increasing apoptosis. Treatment with the three isolated molecules resulted in reduced tumor size and weight in vivo and slowed leukemia progression in mice models. Altogether, this study elucidated the mechanism of action of three distinct cannabinoids in modulating the Notch1 pathway, and constitutes an important step in the establishment of a new therapy for treating NOTCH1-mutated diseases and cancers such as T-ALL.

[Role of Notch 1 signaling and glycolysis in the pathogenic mechanism of adenomyosis].

OBJECTIVE: To investigate the expressions of glycolysis-related factors and changes in Notch1 signaling in endometrial tissues of adenomyosis (AM) and Ishikawa cells to explore the pathogenesis of AM. METHODS: Eutopic endometrial tissues were collected from 8 patients with AM and 8 patients with uterine fibroids matched for clinical characteristics (control group). The expressions of Notch1 signaling proteins and glycolysis-related factors in the collected tissues were detected using qRT-PCR and Western blotting, and the levels of glucose and lactic acid were determined. An Ishikawa cell model with lentivirus-mediated stable Notch1 overexpression was established for assessing cell survival rate with CCK-8 assay, cell migration and invasion abilities with Transwell migration and invasion assays, and glycolytic capacity by determining the extracellular acidification rate. RESULTS: Compared with those in the control group, the endometrial tissues in AM group showed significantly increased expression level of carbohydrate antigen 125 (CA125), increased mRNA expression levels of Notch1, HK2 and PDHA and protein expressions of Notch1, GLUT1, HK2, PKM and PDHA, lowered glucose level and increased lactate level. The Ishikawa cell models with stable Notch1 overexpression exhibited significantly increased cell survival rate with attenuated cell migration and invasion abilities and decreased glycolysis capacity and reserve. CONCLUSION: The Notch1 signaling pathway participates in the pathogenesis of AM possibly by regulating the proliferation, migration, invasion and glycolysis of endometrial cells.

Notch1 signaling pathway promotes growth and metastasis of gastric cancer via modulating CDH5.

OBJECTIVE: To explore the underlying molecular mechanism of Notch1/cadherin 5 (CDH5) pathway in modulating in cell malignant behaviors of gastric cancer (GC). METHODS: We performed bioinformatic analyses to screen the potential target genes of Notch1 from cadherins in GC. Western blot and RT-PCR were conducted to detect CDH5 expression in GC tissues and cells. We utilized chromatin immunoprecipitation (CHIP) assays to assess the interaction of Notch1 with CDH5 gene. The effects of Notch1/CDH5 axis on the proliferation, invasion, migration and vasculogenic mimicry in GC cells were evaluated by EdU, wound healing, transwell, and tubule formation assays. RESULTS: Significantly increased CDH5 expression was found in GC tissues compared with paracancerous tissues and associated to clinical stage and poor overall survival (OS) in patients with GC. Notch1 positively regulate the expression of CDH5 in GC cells. CHIP assays validated that CDH5 was a direct target of Notch1. In addition, Notch1 upregulation enhanced the proliferation, migration, invasion and vasculogenic mimicry capacity of GC cells, which could be attenuated by CDH5 silencing. CONCLUSIONS: These results indicated Notch1 upregulation enhanced GC malignant behaviors by triggering CDH5, suggesting that targeting Notch1/CDH5 axis could be a potential therapeutic strategy for GC progression.

The new pattern for dual NOTCH pathway involving nuclear transcription and mitochondrial regulation supports therapeutic mechanism of 4-butyl benzophenone derivatives against SIRS.

The systemic inflammatory response syndrome (SIRS) represents a self-amplifying cascade of inflammatory reactions and pathophysiological states triggered by infectious or non-infectious factors. The identification of disease targets and differential proteins in the liver (the unique and important immune organ) of SIRS mice treated with the lead compound D1 was conducted using the Genecards database and proteomic analysis, respectively. Subsequently, NOTCH1 was identified as the potential hub target via an intersection analysis between the aforementioned differentially expressed proteins and disease targets. Based on our previous research on the structure-activity relationship, we designed and synthesized a series of SIRS-related derivatives, wherein butyl, halogen, and ester groups were incorporated into benzophenone, aiming at exploring the anti-inflammatory protective action from the perspective of macrophage polarization. Notably, these derivatives exhibited a direct binding capability to the O-glucosylation site (SER496) or its vicinities (such as SER492, VAL485) of NOTCH1 using docking, SPR, DARTS, and CETSA techniques. Mechanistically, derivative D6 exerted anti-inflammatory effects via the dual NOTCH pathway. Firstly, it could inhibit NOTCH1 nuclear transcriptional activity, attenuate the interaction between NICD and RBPJK, concurrently suppress NF-κB and NLRP3 inflammasome (NLRP3, ASC, and cleaved CASP1) activation, and promote NICD (NOTCH1 active fragments) ubiquitination metabolism (the nuclear transcriptional pathway). Secondly, it might possess the ability to increase PGC1α level, subsequently, enhance ATP and MMP levels, mitigate ROS production, increase mitochondrial numbers, and ameliorate mitochondrial inflammatory damage (the mitochondrial pathway). Importantly, the activator Jagged1 could effectively reverse the aforementioned effects, while the inhibitor DAPT exhibited a synergistic effect, suggesting that the nuclear transcriptional regulation and mitochondrial regulation were both in a NOTCH1-dependent manner. Subsequently, it effectively alleviated the inflammatory response and preserved organ function as evidenced by up-regulating M2-type macrophage-related anti-inflammatory cytokines (IL10, TGFß, CD206, and ARG1) and down-regulating M1-type macrophage-related pro-inflammatory cytokines (NO, IL6, IL18, iNOS, TNFα, CD86, and IL1ß). In a word, derivative D6 modulated macrophage polarization and effectively mitigated SIRS by targeting inhibition of the dual NOTCH pathway.

Radix rehmanniae praeparata extracts ameliorate hepatic ischemia-reperfusion injury by reversing LRP1-NOTCH1-C/EBPß axis-mediated senescence fate of LSECs.

BACKGROUND: Hepatic ischemia-reperfusion injury (HIRI) is commonly observed in cases of extensive hepatic resection and involves complex mechanisms. Cell senescence has been recognized as a factor in liver injury including HIRI, where it presents as a pro-inflammatory phenotype called senescence-associated secretory phenotype (SASP). Radix Rehmanniae Praeparata (RRP) is a commonly utilized traditional Chinese medicine known for its hepatoprotective, anti-aging and antioxidant qualities. Despite its recognized benefits, the specific mechanisms by which RRP may impede the progression of HIRI through the regulation of cell senescence and the identification of the most potent anti-aging extracts from RRP remain unclear. MATERIALS AND METHODS: Here, we first applied different chemical analysis methods to identify the RRP aqueous extract (RRPAE) and active fractions of RRP. Next, we constructed a surgically established mouse model and a hypoxia-reoxygenation (HR)-stimulated liver sinusoidal endothelial cells (LSECs) model to explore the underlying mechanism of RRP against HIRI through transcriptomics and multiple molecular biology experiments. RESULTS: After identifying active ingredients in RRP, we observed that RRP and its factions effectively restored LSECs fenestration and improved inflammation, cellular swelling and vascular continuity in the hepatic sinusoidal region during HIRI. Transcriptomic results revealed that RRP might reverse HIRI-induced senescence through the NOTCH signaling pathway and cell categorization further showed that the senescent cell population in HIRI liver was primarily LSECs rather than other cell types. Different RRPAE, especially RRP glucoside (RRPGLY), improved LSECs senescence and suppressed the expression of pro-inflammatory SASP genes either induced by HR insult or NOTCH1 activator, which was accompanied with the inhibition of LRP1-NOTCH1-C/EBPß pathways. Additionally, the specific inhibition of NOTCH1 by siRNA synergistically enhanced the hepatoprotective effect of RRPGLY. The ChIP-qPCR results further showed that C/EBPß was enriched at the promoter of a representative SASP, Il-1ß, in hypoxic LSECs but was significantly inhibited by RRPGLY. CONCLUSION: Our study not only clarified the potential mechanism of RRP active extractions in alleviating HIRI, but also highlighted RRPGLY was the main component of RRP that exerted anti-aging and anti-HIRI effects, providing a fresh perspective on the use of RRP to improve HIRI.

Activated dormant stem cells recover spermatogenesis in chemoradiotherapy-induced infertility.

Male infertility is a recognized side effect of chemoradiotherapy. Extant spermatogonial stem cells (SSCs) may act as originators for any subsequent recovery. However, which type of SSCs, the mechanism by which they survive and resist toxicity, and how they act to restart spermatogenesis remain largely unknown. Here, we identify a small population of Set domain-containing protein 4 (Setd4)-expressing SSCs that occur in a relatively dormant state in the mouse seminiferous tubule. Extant beyond high-dose chemoradiotherapy, these cells then activate to recover spermatogenesis. Recovery fails when Setd4+ SSCs are deleted. Confirmed to be of fetal origin, these Setd4+ SSCs are shown to facilitate early testicular development and also contribute to steady-state spermatogenesis in adulthood. Upon activation, chromatin remodeling increases their genome-wide accessibility, enabling Notch1 and Aurora activation with corresponding silencing of p21 and p53. Here, Setd4+ SSCs are presented as the originators of both testicular development and spermatogenesis recovery in chemoradiotherapy-induced infertility.

Rbm24/Notch1 signaling regulates adult neurogenesis in the subventricular zone and mediates Parkinson-associated olfactory dysfunction.

Rationale: Adult neurogenesis in the subventricular zone (SVZ) is essential for maintaining neural homeostasis, and its dysregulation contributes to anosmia and delayed tissue healing in neurological disorders, such as Parkinson's disease (PD). Despite intricate regulatory networks identified in SVZ neurogenesis, the molecular mechanisms dynamically maintaining neural stem/progenitor cells (NSPCs) in response to physiological and pathological stimuli remain incompletely elucidated. Methods: We generated an RNA binding motif protein 24 (Rbm24) knockout model to investigate its impact on adult neurogenesis in the SVZ, employing immunofluorescence, immunoblot, electrophysiology, RNA-sequencing, and in vitro experiments. Further investigations utilized a PD mouse model, along with genetic and pharmacological manipulations, to elucidate Rbm24 involvement in PD pathology. Results: Rbm24, a multifaceted post-transcriptional regulator of cellular homeostasis, exhibited broad expression in the SVZ from development to aging. Deletion of Rbm24 significantly impaired NSPC proliferation in the adult SVZ, ultimately resulting in collapsed neurogenesis in the olfactory bulb. Notably, Rbm24 played a specific role in maintaining Notch1 mRNA stability in adult NSPCs. The Rbm24/Notch1 signaling axis was significantly downregulated in the SVZ of PD mice. Remarkably, overexpression of Rbm24 rescued disruption of adult neurogenesis and olfactory dysfunction in PD mice, and these effects were hindered by DAPT, a potent inhibitor of Notch1. Conclusions: Our findings highlight the critical role of the Rbm24/Notch1 signaling axis in regulating adult SVZ neurogenesis under physiological and pathological circumstances. This provides valuable insights into the dynamic regulation of NSPC homeostasis and offers a potential targeted intervention for PD and related neurological disorders.

Notch transcriptional target tmtc1 maintains vascular homeostasis.

Proper lung function requires the maintenance of a tight endothelial barrier while simultaneously permitting the exchange of macromolecules and fluids to underlying tissue. Disruption of this barrier results in an increased vascular permeability in the lungs, leading to acute lung injury. In this study, we set out to determine whether transcriptional targets of Notch signaling function to preserve vascular integrity. We tested the in vivo requirement for Notch transcriptional signaling in maintaining the pulmonary endothelial barrier by using two complementary endothelial-specific Notch loss-of-function murine transgenic models. Notch signaling was blocked using endothelial-specific activation of an inhibitor of Notch transcriptional activation, Dominant Negative Mastermindlike (DNMAML; CDH5CreERT2), or endothelial-specific loss of Notch1 (Notch1f/f; CDH5CreERT2). Both Notch mutants increased vascular permeability with pan-Notch inhibition by DNMAML showing a more severe phenotype in the lungs and in purified endothelial cells. RNA sequencing of primary lung endothelial cells (ECs) identified novel Notch targets, one of which was transmembrane O-mannosyltransferase targeting cadherins 1 (tmtc1). We show that tmtc1 interacts with vascular endothelial cadherin (VE-cadherin) and regulates VE-cadherin egress from the endoplasmic reticulum through direct interaction. Our findings demonstrate that Notch signaling maintains endothelial adherens junctions and vascular homeostasis by a transcriptional mechanism that drives expression of critical factors important for processing and transport of VE-cadherin.

ALYREF promotes the metastasis of nasopharyngeal carcinoma by increasing the stability of NOTCH1 mRNA.

Approximately 70% of treatment failures in nasopharyngeal carcinoma (NPC) patients are attributed to distant metastasis, yet the underlying mechanisms remain unclear. RNA 5-methylcytosine (m5C) is an emerging regulatory modification that controls gene expression and plays a critical role in tumor progression. However, there is little information on the potential roles of RNA m5C modification in NPC metastasis. In this study, we found that the m5C reader Aly/REF export factor (ALYREF) is significantly upregulated in NPC, whereby its high expression is associated with metastasis and poor prognosis. ALYREF overexpression was found to promote tumor metastasis of NPC cells in vitro and in vivo. Mechanistically, m5C-modified NOTCH1 mRNA was identified as a target of ALYREF. Moreover, ALYREF was found to upregulate NOTCH1 expression by enhancing its RNA stability in an m5C modification-dependent manner, thereby promoting the activation of the NOTCH signaling pathway and facilitating NPC metastasis. Overall, our data reveal the crucial role of ALYREF in NPC metastasis and provide a potential therapeutic target for NPC.

The Foxo1-YAP-Notch1 axis reprograms STING-mediated innate immunity in NASH progression.

Innate immune activation is critical for initiating hepatic inflammation during nonalcoholic steatohepatitis (NASH) progression. However, the mechanisms by which immunoregulatory molecules recognize lipogenic, fibrotic, and inflammatory signals remain unclear. Here, we show that high-fat diet (HFD)-induced oxidative stress activates Foxo1, YAP, and Notch1 signaling in hepatic macrophages. Macrophage Foxo1 deficiency (Foxo1M-KO) ameliorated hepatic inflammation, steatosis, and fibrosis, with reduced STING, TBK1, and NF-κB activation in HFD-challenged livers. However, Foxo1 and YAP double knockout (Foxo1/YAPM-DKO) or Foxo1 and Notch1 double knockout (Foxo1/Notch1M-DKO) promoted STING function and exacerbated HFD-induced liver injury. Interestingly, Foxo1M-KO strongly reduced TGF-ß1 release from palmitic acid (PA)- and oleic acid (OA)-stimulated Kupffer cells and decreased Col1α1, CCL2, and Timp1 expression but increased MMP1 expression in primary hepatic stellate cells (HSCs) after coculture with Kupffer cells. Notably, PA and OA challenge in Kupffer cells augmented LIMD1 and LATS1 colocalization and interaction, which induced YAP nuclear translocation. Foxo1M-KO activated PGC-1α and increased nuclear YAP activity, modulating mitochondrial biogenesis. Using chromatin immunoprecipitation (ChIP) coupled with massively parallel sequencing (ChIP-Seq) and in situ RNA hybridization, we found that NICD colocalizes with YAP and targets Mb21d1 (cGAS), while YAP functions as a novel coactivator of the NICD, which is crucial for reprogramming STING function in NASH progression. These findings highlight the importance of the macrophage Foxo1-YAP-Notch1 axis as a key molecular regulator that controls lipid metabolism, inflammation, and innate immunity in NASH.

Vasorin (VASN) overexpression promotes pulmonary metastasis and resistance to adjuvant chemotherapy in patients with locally advanced rectal cancer.

BACKGROUND: LARC patients commonly receive adjuvant therapy, however, hidden micrometastases still limit the improvement of OS. This study aims to investigate the impact of VASN in rectal cancer with pulmonary metastasis and understand the underlying molecular mechanisms to guide adjuvant chemotherapy selection. METHODS: Sequencing data from rectal cancer patients with pulmonary metastasis from Sun Yat-sen University Cancer Center (SYSUCC) and publicly available data were meticulously analyzed. The functional role of VASN in pulmonary metastasis was validated in vivo and in vitro. Coimmunoprecipitation (co-IP), immunofluorescence, and rescue experiments were conducted to unravel potential molecular mechanisms of VASN. Moreover, VASN expression levels in tumor samples were examined and analyzed for their correlations with pulmonary metastasis status, tumor stage, adjuvant chemotherapy benefit, and survival outcome. RESULTS: Our study revealed a significant association between high VASN expression and pulmonary metastasis in LARC patients. Experiments in vitro and in vivo demonstrated that VASN could promote the cell proliferation, metastasis, and drug resistance of colorectal cancer. Mechanistically, VASN interacts with the NOTCH1 protein, leading to concurrent activation of the NOTCH and MAPK pathways. Clinically, pulmonary metastasis and advanced tumor stage were observed in 90% of VASN-positive patients and 53.5% of VASN-high patients, respectively, and VASN-high patients had a lower five-year survival rate than VASN-low patients (26.7% vs. 83.7%). Moreover, the Cox analysis and OS analysis indicated that VASN was an independent prognostic factor for OS (HR = 7.4, P value < 0.001) and a predictor of adjuvant therapy efficacy in rectal cancer. CONCLUSIONS: Our study highlights the role of VASN in decreasing drug sensitivity and activating the NOTCH and MAPK pathways, which leads to tumorigenesis and pulmonary metastasis. Both experimental and clinical data support that rectal cancer patients with VASN overexpression detected in biopsies have a higher risk of pulmonary metastasis and adjuvant chemotherapy resistance.

TCF12-regulated GRB7 facilitates the HER2+ breast cancer progression by activating Notch1 signaling pathway.

BACKGROUND: Human epidermal growth factor receptor 2-positive (HER2+) breast cancer (BC), which accounts for approximately one-fifth of all BCs, are highly invasive with a high rate of recurrence and a poor prognosis. Several studies have shown that growth factor receptor-bound protein 7 (GRB7) might be a potential therapeutic target for tumor diagnosis and prognosis. Nevertheless, the role of GRB7 in HER2+ BC and its underlying mechanisms have not been fully elucidated. The aim of this study was to investigate the biological function and regulatory mechanism of GRB7 in HER2+ BC. METHODS: Bioinformatics analysis was performed using the TCGA, GEO and CancerSEA databases to evaluate the clinical significance of GRB7. RT quantitative PCR, western blot and immunofluorescence were conducted to assess the expression of GRB7 in BC cell lines and tissues. MTT, EdU, colony formation, wound healing, transwell, and xenograft assays were adopted to explore the biological function of GRB7 in HER2+ BC. RNA sequencing was performed to analyze the signaling pathways associated with GRB7 in SK-BR-3 cells after the cells were transfected with GRB7 siRNA. Chromatin immunoprecipitation analysis (ChIP) and luciferase reporter assay were employed to elucidate the potential molecular regulatory mechanisms of GRB7 in HER2+ BC. RESULTS: GRB7 was markedly upregulated and associated with poor prognosis in BC, especially in HER2+ BC. Overexpression of GRB7 increased the proliferation, migration, invasion, and colony formation of HER2+ BC cells, while depletion of GRB7 had the opposite effects in HER2+ BC cells and inhibited xenograft growth. ChIP-PCR and luciferase reporter assay revealed that TCF12 directly bound to the promoter of the GRB7 gene to promote its transcription. GRB7 facilitated HER2+ BC epithelial-mesenchymal transition (EMT) progression by interacting with Notch1 to activate Wnt/ß-catenin pathways and other signaling (i.e., AKT, ERK). Moreover, forced GRB7 overexpression activated Wnt/ß-catenin to promote EMT progression, and partially rescued the inhibition of HER2+ BC proliferation, migration and invasion induced by TCF12 silencing. CONCLUSIONS: Our work elucidates the oncogenic role of GRB7 in HER2+ BC, which could serve as a prognostic indicator and promising therapeutic target.