Coronary microvascular dysfunction and autoregulatory capacity interfere with resting Dicrotic notch morphology.

Coronary microvascular vasodilator capacity is substantially associated with coronary pressure waveform and dicrotic notch morphology, with or without concomitant epicardial disease. A prominent dicrotic notch is associated with preserved microvascular vasodilatory capacity and adequate resting microvascular tonus without relative hyperaemic state, cumulatively indicating a better microcirculatory health.

Circ_0104873 promotes osteoarthritis progression via miR-875-5p/NOTCH3/Notch signaling pathway.

Osteoarthritis (OA) is the most common joint disease with high prevalence and incidence. Increasing reports has indicated that circular RNAs (circRNAs) are implicated in OA progression. Nevertheless, the roles and functions of most circRNAs in OA remain to be elucidated. In this study, we emphatically discussed circ-IQGAP1 (circ_0104873) in OA. Firstly, we discovered that circ_0104873 was dramatically overexpressed during osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). Several functional assays demonstrated that circ_0104873 inhibition repressed BMSCs proliferation and osteogenic differentiation. Moreover, mechanism assays also revealed that circ_0104873 sponged microRNA-875-5p (miR-875-5p) to up-regulate notch receptor 3 (NOTCH3), thereby activating the Notch signaling pathway. Rescue assays disclosed that circ_0104873 contributed to the development of OA via targeting miR-875-5p/NOTCH3 axis. In conclusion, circ_0104873 promoted the progression of OA by miR-875-5p/NOTCH3/Notch signaling pathway, which might provide a promising target for OA treatment.

What Makes Us Human: Insights from the Evolution and Development of the Human Neocortex.

"What makes us human?" is a central question of many research fields, notably anthropology. In this review, we focus on the development of the human neocortex, the part of the brain with a key role in cognition, to gain neurobiological insight toward answering this question. We first discuss cortical stem and progenitor cells and human-specific genes that affect their behavior. We thus aim to understand the molecular foundation of the expansion of the neocortex that occurred in the course of human evolution, as this expansion is generally thought to provide a basis for our unique cognitive abilities. We then review the emerging evidence pointing to differences in the development of the neocortex between present-day humans and Neanderthals, our closest relatives. Finally, we discuss human-specific genes that have been implicated in neuronal circuitry and offer a perspective for future studies addressing the question of what makes us human.

[Molecular profiling of myeloid/natural killer (NK) cell precursor acute leukemia].

Myeloid/natural killer (NK) cell precursor acute leukemia (MNKPL) has been described based on its clinical phenotype and immunophenotype, and proposed as a unique leukemia entity. However, due to its rarity and lack of defined distinctive molecular characteristics, there is currently no international consensus on this disease concept. We performed multi-omics analysis and revealed that MNKPL is distinct from acute myeloid leukemia, T-cell acute lymphoblastic leukemia, and mixed-phenotype acute leukemia. NOTCH1 and RUNX3 activation and BCL11B downregulation are hallmarks of MNKPL. Although NK cells have been classically considered to be lymphoid lineage-derived, our single-cell analysis using MNKPL cells suggested that NK cells and myeloid cells share common progenitor cells. Our retrospective case study uncovered that outcomes of MNKPL are unsatisfactory, even with hematopoietic cell transplantation. Multi-omics analysis and in vitro drug sensitivity assays revealed increased sensitivity to L-asparaginase and reduced levels of asparagine synthetase, supporting the clinically observed effectiveness of L-asparaginase.

Jag1 insufficiency alters liver fibrosis via T cell and hepatocyte differentiation defects.

Fibrosis contributes to tissue repair, but excessive fibrosis disrupts organ function. Alagille syndrome (ALGS, caused by mutations in JAGGED1) results in liver disease and characteristic fibrosis. Here, we show that Jag1Ndr/Ndr mice, a model for ALGS, recapitulate ALGS-like fibrosis. Single-cell RNA-seq and multi-color flow cytometry of the liver revealed immature hepatocytes and paradoxically low intrahepatic T cell infiltration despite cholestasis in Jag1Ndr/Ndr mice. Thymic and splenic regulatory T cells (Tregs) were enriched and Jag1Ndr/Ndr lymphocyte immune and fibrotic capacity was tested with adoptive transfer into Rag1-/- mice, challenged with dextran sulfate sodium (DSS) or bile duct ligation (BDL). Transplanted Jag1Ndr/Ndr lymphocytes were less inflammatory with fewer activated T cells than Jag1+/+ lymphocytes in response to DSS. Cholestasis induced by BDL in Rag1-/- mice with Jag1Ndr/Ndr lymphocytes resulted in periportal Treg accumulation and three-fold less periportal fibrosis than in Rag1-/- mice with Jag1+/+ lymphocytes. Finally, the Jag1Ndr/Ndr hepatocyte expression profile and Treg overrepresentation were corroborated in patients' liver samples. Jag1-dependent hepatic and immune defects thus interact to determine the fibrotic process in ALGS.

The activation of the Notch signaling pathway by UBE2C promotes the proliferation and metastasis of hepatocellular carcinoma.

UBE2C, a ubiquitin-conjugating enzyme, functions as an oncogene in different types of human cancers. Nonetheless, the exact influence of UBE2C on the development of HCC via regulation of ubiquitination remains uncertain. Here, we found that UBE2C displayed elevated levels of expression in HCC and was associated with an unfavorable prognosis, as evidenced by the analysis of the TCGA database and the examination of clinical specimens. The role of UBE2C in HCC revealed its ability to promote the growth and metastasis of HCC. Mechanistically, UBE2C activated Notch signaling, as evidenced by the upregulation of N1ICD and Hes1, crucial components of the Notch pathway, and activation of the RBP-JK luciferase reporter by UBE2C. Finally, rescue experiments demonstrated that the oncogenic role of UBE2C was eliminated through treatment with the Notch inhibitor DAPT, while overexpression of N1ICD alleviated the anticarcinogenic impact of knockdown of UBE2C. Altogether, the results of our study indicate that UBE2C plays a role in the activation of Notch signaling and could potentially serve as a viable target for therapeutic interventions in HCC.

A cephalometric analysis of the antegonial notch in relation to the direction of mandibular growth.

Masticatory muscle forces influence craniofacial morphology development. The antegonial notch (Notch) is a bony concavity on the inferior border of the mandible. Considering the Notch is located anteriorly to the insertion of the masseter muscle and varies among individuals, we hypothesised that these muscles influence the formation of the Notch. Therefore, this study aimed to investigate the correlation between mandible morphology and Notch formation. Sixty Japanese patients who visited the Department of Orthodontics at our university hospital were retrospectively evaluated. Morphological and morphometric analyses of the Notch and related craniofacial parameters were conducted using lateral cephalograms taken at the patients' initial visits. Standard values for the Notch area and depth were determined, and the morphology of the Notch and mandible was analysed using Spearman's rank correlation coefficient (p < 0.05). The mean Notch area and depth was 78.71 ± 36.54 mm2 and 3.11 ± 1.09 mm, respectively. The Notch area was significantly correlated with ramus inclination (p = 0.044, r = 0.261) and with the Y-axis (p = 0.039, r = 0.267). This study indicated that both the masticatory muscles and mandibular growth could contribute to the Notch formation.

Jag1 represses Notch activation in lateral supporting cells and inhibits an outer hair cell fate in the medial cochlea.

Notch signaling patterns the cochlear organ of Corti, and patients with the JAG1/NOTCH2-related genetic disorder Alagille syndrome can thus experience hearing loss. We investigated the function of Jag1 in cochlear patterning and signaling using Jag1Ndr/Ndr mice, a model of Alagille syndrome. Jag1Ndr/Ndr mice exhibited expected vestibular and auditory deficits, a dose-dependent increase in ectopic inner hair cells, and a reduction in outer hair cells. Single cell RNA sequencing of the organ of Corti demonstrated a global dysregulation of genes associated with inner ear development and deafness. Analysis of individual cell types further revealed that Jag1 represses Notch activation in lateral supporting cells and demonstrated a function for Jag1 in gene regulation and development of outer hair cells. Surprisingly, ectopic "outer hair cell-like" cells were present in the medial compartment and pillar cell region of Jag1Ndr/Ndr cochleae, yet they exhibited location-dependent expression of the inner hair cell fate-determinant Tbx2, suggesting Jag1 is required for Tbx2 to drive inner hair cell commitment. This study thus identifies new roles for Jag1 in supporting cells, and in outer hair cell specification and positioning.

Notch-Driven Cholangiocarcinogenesis Involves the Hippo Pathway Effector TAZ via METTL3-m6A-YTHDF1.

BACKGROUND AND AIMS: Notch and TAZ are implicated in cholangiocarcinogenesis, but whether and how these oncogenic molecules interact remain unknown. METHODS: The development of CCA was induced by hydrodynamic tail vein (HDTV) injection of oncogenes (NICD/AKT) to the FVB/NJ mice. CCA xenograft was developed by inoculation of human CCA cells into the livers of SCID mice. Tissues and cells were analyzed using qRT-PCR, Western blotting analyses, Immunohistochemistry, ChIP-qPCR and WST-1 cell proliferation Assay. RESULTS: Our experimental findings show that TAZ is indispensable in NICD-driven cholangiocarcinogenesis. Notch activation induces the expression of METTL3 (Methyltransferase like-3) which catalyzes N6-methyladenosine (m6A) modification of TAZ mRNA and that this mechanism plays a central role in the crosstalk between Notch and TAZ in CCA cells. Mechanistically, Notch regulates the expression of METTL3 through the binding of NICD to its downstream transcription factor CSL in the promoter region of METTL3. METTL3 in turn mediates m6A modification of TAZ mRNA which is recognized by the m6A reader YTHDF1 to enhance TAZ protein translation. We observed that inhibition of Notch signaling decreased the protein levels of both MELLT3 and TAZ. Depletion of METTL3 by shRNAs or by the next generation GapmeR antisense oligonucleotides (ASOs) decreased the level of TAZ protein and inhibited the growth of human CCA cells in vitro and in mice. CONCLUSION: This study describes a novel Notch-METTL3-TAZ signaling cascade which is important in CCA development and progression. Our experimental results provide new insight into how the Notch pathway cooperates with TAZ signaling in CCA, and the findings may have important therapeutic implications.

PLGA-Loaded Nedaplatin (PLGA-NDP) Inhibits 7,12-Dimethylbenz[a]anthracene (DMBA) Induced Oral Carcinogenesis via Modulating Notch Signaling Pathway and Induces Apoptosis in Experimental Hamster Model.

The present study is designed to evaluate the nanotherapeutic efficacy of prepared PLGA-loaded Nedaplatin (PLGA-NDP) against 7,12-dimethyl benz(a)anthracene (DMBA)-induced experimental oral carcinogenesis in hamster buccal pouch (HBP) model. The buccal pouch of golden Syrian hamsters was painted with 0.5% DMBA in liquid paraffin three times a week for 14 weeks, ultimately leading to the development of oral squamous cell carcinoma (OSCC). Oral administration of PLGA-NDP (preinitiation) and Cisplatin delivery (5 mg/kg b.wt) started 1 week before the carcinogen exposure and continued on alternative days. Post-administration of PLGA-NDP (5 mg/kg b.wt) started 2 days after carcinogen (DMBA) induction until the end of the experiment. After the 14th week, we observed that DMBA-painted hamsters exhibited tumor formation, morphological alterations, and well-differentiated OSSC in addition to the responsive molecular proteins during oral carcinogenesis. Furthermore, immunoblotting analysis demonstrated that PLGA-NDP inhibits Notch signaling, as evidenced by downregulation of Bcl-Xl, Bcl-2, p21, PGE2, HGF, and CXCL12 proteins, and upregulation of p53 and Bax. This apoptotic response is crucial for PLGA-NDP to induce apoptosis. In addition, RT-PCR results showed that PLGA-NDP nanoparticles play a downregulatory role in the therapeutic action of the notch signaling gene (Notch1, Notch 2, Hes1, Hey1, and Jagged1) at the mRNA transcription level in HBP carcinoma. Taken together, these data indicate that PLGA-NDP is a potent inhibitor of oral carcinogenesis and the expansion of cells that specifically target the Notch signaling pathway indicates that obstructing Notch signaling could potentially serve as a new and innovative therapeutic approach for oral squamous cell carcinoma (OSCC).

Audiological Profile of a Rare Case with 1 kHz Notch Audiogram.

A notch is defined as the frequency point at which hearing loss is greater than 15 dB when compared to one octave above and below. C3 dip or 1 kHz notch is rarely seen and not much information is known about the clinical profile of such condition. The aim of this case report is to highlight the audiological profile of a case with 1kHz notch and discuss the possible causes for the same. Case A (16 yrs) was referred with a complaint of hearing loss and speech understanding difficulty specially at school. The teen had taken multiple medications for several health related issues like malaria, appendicitis and the understanding difficulty was evident during this period. Detailed audiological evaluation revealed a significant C3 dip in the right ear and normal hearing sensitivity in the left ear. Evidences from literature suggests strong correlation between drugs like Cefotetan, cefotaime, piperacillin, ampicillin (appendicitis treatment) and chloroquine (malaria) and hearing loss. Hence, we concluded that the possible cause of 1khz is ototoxic medication.

The effect of bisphenol A on the Notch (Notch2 and Jagged2) signaling pathway in the follicular development of the neonatal rat ovary.

The formation of primordial follicles determines the pool size of follicles in the ovary, and is crucial for female reproductivity. Oocyte nest breakdown, and the formation of primordial follicles, largely depend upon the communication between oocytes and the surrounding pregranulosa cells. The neurogenic locus notch homolog protein (Notch) signaling pathway is the key player for this cell-to-cell communication, and is responsible for primordial folliculogenesis. However, different endocrine disruptors, including bisphenol A (BPA; a plasticizer and a constituent of reusable plastic containers) may affect the Notch signaling pathway, and might induce ovary dysfunction via Notch signaling. Consequently, we investigated the possible influence of BPA treatment on the proportional distribution of the follicular stages, follicle numbers, levels of apoptosis, and on Notch2 and Jagged2 expressions in the ovary. BPA was administered at doses of either 50 µg/kg/day or 50 mg/kg/day, at different time intervals, during neonatal and fetal periods in vivo. After collecting the ovaries from the various experimental groups, follicles were counted, and frequency of apoptosis was determined by TUNEL assay. In addition, Notch2 and Jagged2 expressions were assessed by immunohistochemical staining and qPCR. In summary, BPA treatment affected the follicle numbers and apoptosis level, and Notch2 and Jagged2 expressions varied with follicular stage. It was also observed that these parameters were dose and time dependent with respect to BPA exposure.

Characteristics and temporal evolution of asymptomatic diffusion-weighted imaging lesions in patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL).

BACKGROUND AND PURPOSE: The role of asymptomatic diffusion-weighted imaging-positive (aDWI+) lesions in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) patients remains unclear, and their radiographic features may differ from those of symptomatic diffusion-weighted imaging-positive (sDWI+) lesions. We aimed to investigate the clinicoradiographic characteristics of aDWI+ lesions in CADASIL patients. METHODS: We conducted a retrospective analysis using data from the Taiwan CADASIL Registry. aDWI+ lesions were defined as incidentally detected DWI+ lesions without corresponding acute neurological deficits. We compared the baseline clinical characteristics of patients with and without aDWI+ lesions and analyzed their radiological features and evolution in relation to sDWI+ lesions. RESULTS: Among 154 enrolled patients (mean age 62 ± 10 years), 17 (11%) had aDWI+ lesions. Baseline clinical characteristics were similar in the two groups, but those with aDWI+ lesions had more lacunes (median 8 vs. 2), multiple cerebral microbleeds (CMBs; 85% vs. 40%), and anterior temporal white matter hyperintensity (WMH; 47% vs. 14%). Multivariable analysis showed that aDWI+ lesions were associated with anterior temporal WMH (odds ratio 5.7, 95% confidence interval 1.5-21.0) after adjusting for multiple lacunes, multiple CMBs, and total WMH score. Compared to sDWI+ lesions, aDWI+ lesions were more often small infarcts (<1 cm; 89% vs. 23%) and less likely to involve the corticospinal tract (11% vs. 96%). Among the 11 aDWI+ lesions with follow-up magnetic resonance imaging, seven became microinfarcts, three became lacunes, and one disappeared. CONCLUSIONS: aDWI+ lesions in CADASIL are not uncommon and are associated with higher burdens of small vessel disease and anterior temporal WMH. Further research is needed to assess their long-term impact on CADASIL.

Oscillatory DeltaC Expression in Neural Progenitors Primes the Prototype of Forebrain Development.

Notch signaling plays a pivotal role in regulating various developmental processes, particularly in controlling the timing of neuronal production within the developing neocortex. Central to this regulatory mechanism is the oscillatory pattern of Delta, which functions as a developmental clock modulator. Its deficiency profoundly impairs mammalian brain formation, highlighting its fundamental role in brain development. However, zebrafish carrying a mutation in the functional ortholog DeltaC (dlc) within their functional ortholog exhibit an intact forebrain structure, implying evolutionary variations in Notch signaling within the forebrain. In this study, we unveil the distinct yet analogous expression profiles of Delta and Her genes in the developing vertebrate forebrain. Specifically, for the first time, we detected the oscillatory expression of the Delta gene dlc in the developing zebrafish forebrain. Although this oscillatory pattern appeared irregular and was not pervasive among the progenitor population, attenuation of the dlc-involved Notch pathway using a γ-secretase inhibitor impaired neuronal differentiation in the developing zebrafish forebrain, revealing the indispensable role of the dlc-involved Notch pathway in regulating early zebrafish neurogenesis. Taken together, our results demonstrate the foundational prototype of dlc-involved Notch signaling in the developing zebrafish forebrains, upon which the intricate patterns of the mammalian neocortex may have been sculpted.

The Transverse Sigmoid Notch Morphology Unravelled.

Background: Several studies have described pathology in relation to transverse sigmoid notch morphology, using the Tolat transverse sigmoid notch classification. It is believed that the entire shape of a sigmoid notch can be described using Tolat sigmoid types. We hypothesised that the determination of the sigmoid notch shape (SNS) depends on the level of the transverse CT plane on the axial axis of the distal radius. The aim of this study was to determine and compare the transverse SNS on different axial CT levels in the same wrist. Methods: The transverse SNS of 53 participants were independently qualitatively classified by two researchers in accordance with the four morphologies described by Tolat et al. The SNS was determined at two levels on the axial axis of the distal radius; at the level of the most prominent part of Lister tubercle, determined on the sagittal plane and at the level of the 'smallest distance between the ulnar head and sigmoid notch' (SDUS). Results: Forty-seven percent of the wrists demonstrated different SNS types according to Tolat classification, depending on the axial level of the CT scan. Interobserver agreement on the transverse sigmoid shape was 87% at Lister tubercle and 85% at SDUS, which can both be interpreted as 'excellent'. Conclusions: Despite an excellent interobserver agreement, 47% of the study population had different transverse sigmoid notch types within the same wrist. We, therefore, conclude that Tolat transverse sigmoid classification may not be useful for the description of potential pathology in relation to the sigmoid notch morphology.

Symmetry breaking and fate divergence during lateral inhibition in Drosophila.

Lateral inhibition mediates alternative cell fate decision and produces regular cell fate patterns with fate symmetry breaking (SB) relying on the amplification of small stochastic differences in Notch activity via an intercellular negative feedback loop. Here, we used quantitative live imaging of endogenous Scute (Sc), a proneural factor, and of a Notch activity reporter to study the emergence of Sensory Organ Precursor cells (SOPs) in the pupal abdomen of Drosophila. SB was observed at low Sc levels and was not preceded by a phase of intermediate Sc expression and Notch activity. Thus, mutual inhibition may only be transient in this context. In support of the intercellular feedback loop model, cell-to-cell variations in Sc levels promoted fate divergence. The size of the apical area of competing cells did not detectably bias this fate choice. Surprisingly, cells that were in direct contact at the time of SB could adopt the SOP fate, albeit at low frequency (10%). These lateral inhibition defects were corrected by cellular rearrangements, not cell fate change, highlighting the role of cell-cell intercalation in pattern refinement.

Notch4 regulatory T cells and SARS-CoV-2 viremia shape COVID19 survival outcome.

BACKGROUND: Immune dysregulation and SARS-CoV-2 plasma viremia have been implicated in fatal COVID-19 disease. However, how these two factors interact to shape disease outcomes is unclear. METHODS: We carried out viral and immunological phenotyping on a prospective cohort of 280 patients with COVID-19 presenting to acute care hospitals in Boston, Massachusetts and Genoa, Italy between June 1, 2020 and February 8, 2022. Disease severity, mortality, plasma viremia, and immune dysregulation were assessed. A mouse model of lethal H1N1 influenza infection was used to analyze the therapeutic potential of Notch4 and pyroptosis inhibition in disease outcome. RESULTS: Stratifying patients based on %Notch4+ Treg cells and/or the presence of plasma viremia identified four subgroups with different clinical trajectories and immune phenotypes. Patients with both high %Notch4+ Treg cells and viremia suffered the most disease severity and 90-day mortality compared to the other groups even after adjusting for baseline comorbidities. Increased Notch4 and plasma viremia impacted different arms of the immune response in SARS-CoV-2 infection. Increased Notch4 was associated with decreased Treg cell amphiregulin expression and suppressive function whereas plasma viremia was associated with increased monocyte cell pyroptosis. Combinatorial therapies using Notch4 blockade and pyroptosis inhibition induced stepwise protection against mortality in a mouse model of lethal H1N1 influenza infection. CONCLUSIONS: The clinical trajectory and survival outcome in hospitalized patients with COVID-19 is predicated on two cardinal factors in disease pathogenesis: viremia and Notch4+ Treg cells. Intervention strategies aimed at resetting the immune dysregulation in COVID-19 by antagonizing Notch4 and pyroptosis may be effective in severe cases of viral lung infection.

Astrocytic DLL4-NOTCH1 signaling pathway promotes neuroinflammation via the IL-6-STAT3 axis.

Under neuroinflammatory conditions, astrocytes acquire a reactive phenotype that drives acute inflammatory injury as well as chronic neurodegeneration. We hypothesized that astrocytic Delta-like 4 (DLL4) may interact with its receptor NOTCH1 on neighboring astrocytes to regulate astrocyte reactivity via downstream juxtacrine signaling pathways. Here we investigated the role of astrocytic DLL4 on neurovascular unit homeostasis under neuroinflammatory conditions. We probed for downstream effectors of the DLL4-NOTCH1 axis and targeted these for therapy in two models of CNS inflammatory disease. We first demonstrated that astrocytic DLL4 is upregulated during neuroinflammation, both in mice and humans, driving astrocyte reactivity and subsequent blood-brain barrier permeability and inflammatory infiltration. We then showed that the DLL4-mediated NOTCH1 signaling in astrocytes directly drives IL-6 levels, induces STAT3 phosphorylation promoting upregulation of astrocyte reactivity markers, pro-permeability factor secretion and consequent blood-brain barrier destabilization. Finally we revealed that blocking DLL4 with antibodies improves experimental autoimmune encephalomyelitis symptoms in mice, identifying a potential novel therapeutic strategy for CNS autoimmune demyelinating disease. As a general conclusion, this study demonstrates that DLL4-NOTCH1 signaling is not only a key pathway in vascular development and angiogenesis, but also in the control of astrocyte reactivity during neuroinflammation.

Airineme-Mediated Intercellular Communication.

Intercellular communication is indispensable across multicellular organisms, and any aberration in this process can give rise to significant anomalies in developmental and homeostatic processes. Thus, a comprehensive understanding of its mechanisms is imperative for addressing human health-related concerns. Recent advances have expanded our understanding of intercellular communication by elucidating additional signaling modalities alongside established mechanisms. Notably, cellular protrusion-mediated long-range communication, characterized by physical contact through thin and elongated cellular protrusions between cells involved in signal transmission and reception, has emerged as a significant intercellular signaling paradigm. This chapter delves into the exploration of a signaling cellular protrusion termed 'airinemes,' discovered in the zebrafish skin. It covers their identified signaling roles and the cellular and molecular mechanisms that underpin their functionality.

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.