Human-Specific NOTCH2NL Genes Expand Cortical Neurogenesis through Delta/Notch Regulation.

The cerebral cortex underwent rapid expansion and increased complexity during recent hominid evolution. Gene duplications constitute a major evolutionary force, but their impact on human brain development remains unclear. Using tailored RNA sequencing (RNA-seq), we profiled the spatial and temporal expression of hominid-specific duplicated (HS) genes in the human fetal cortex and identified a repertoire of 35 HS genes displaying robust and dynamic patterns during cortical neurogenesis. Among them NOTCH2NL, human-specific paralogs of the NOTCH2 receptor, stood out for their ability to promote cortical progenitor maintenance. NOTCH2NL promote the clonal expansion of human cortical progenitors, ultimately leading to higher neuronal output. At the molecular level, NOTCH2NL function by activating the Notch pathway through inhibition of cis Delta/Notch interactions. Our study uncovers a large repertoire of recently evolved genes active during human corticogenesis and reveals how human-specific NOTCH paralogs may have contributed to the expansion of the human cortex.

Human-Specific NOTCH2NL Genes Affect Notch Signaling and Cortical Neurogenesis.

Genetic changes causing brain size expansion in human evolution have remained elusive. Notch signaling is essential for radial glia stem cell proliferation and is a determinant of neuronal number in the mammalian cortex. We find that three paralogs of human-specific NOTCH2NL are highly expressed in radial glia. Functional analysis reveals that different alleles of NOTCH2NL have varying potencies to enhance Notch signaling by interacting directly with NOTCH receptors. Consistent with a role in Notch signaling, NOTCH2NL ectopic expression delays differentiation of neuronal progenitors, while deletion accelerates differentiation into cortical neurons. Furthermore, NOTCH2NL genes provide the breakpoints in 1q21.1 distal deletion/duplication syndrome, where duplications are associated with macrocephaly and autism and deletions with microcephaly and schizophrenia. Thus, the emergence of human-specific NOTCH2NL genes may have contributed to the rapid evolution of the larger human neocortex, accompanied by loss of genomic stability at the 1q21.1 locus and resulting recurrent neurodevelopmental disorders.

Chemistry-First Approach for Nomination of Personalized Treatment in Lung Cancer.

Diversity in the genetic lesions that cause cancer is extreme. In consequence, a pressing challenge is the development of drugs that target patient-specific disease mechanisms. To address this challenge, we employed a chemistry-first discovery paradigm for de novo identification of druggable targets linked to robust patient selection hypotheses. In particular, a 200,000 compound diversity-oriented chemical library was profiled across a heavily annotated test-bed of >100 cellular models representative of the diverse and characteristic somatic lesions for lung cancer. This approach led to the delineation of 171 chemical-genetic associations, shedding light on the targetability of mechanistic vulnerabilities corresponding to a range of oncogenotypes present in patient populations lacking effective therapy. Chemically addressable addictions to ciliogenesis in TTC21B mutants and GLUT8-dependent serine biosynthesis in KRAS/KEAP1 double mutants are prominent examples. These observations indicate a wealth of actionable opportunities within the complex molecular etiology of cancer.

Programs for the persistence, vigilance and control of human CD8+ lung-resident memory T cells.

Tissue-resident memory T cells (TRM cells) in the airways mediate protection against respiratory infection. We characterized TRM cells expressing integrin αE (CD103) that reside within the epithelial barrier of human lungs. These cells had specialized profiles of chemokine receptors and adhesion molecules, consistent with their unique localization. Lung TRM cells were poised for rapid responsiveness by constitutive expression of deployment-ready mRNA encoding effector molecules, but they also expressed many inhibitory regulators, suggestive of programmed restraint. A distinct set of transcription factors was active in CD103+ TRM cells, including Notch. Genetic and pharmacological experiments with mice revealed that Notch activity was required for the maintenance of CD103+ TRM cells. We have thus identified specialized programs underlying the residence, persistence, vigilance and tight control of human lung TRM cells.

NOTCH2 promotes osteoclast maturation and metabolism and modulates the transcriptome profile during osteoclastogenesis.

Notch signaling plays a key regulatory role in bone remodeling and NOTCH2 enhances osteoclastogenesis, an effect that is mostly mediated by its target gene Hes1. In the present study, we explored mechanisms responsible for the enhanced osteoclastogenesis in bone marrow-derived macrophages (BMM) from Notch2tm1.1Ecan, harboring a NOTCH2 gain-of-function mutation, and control mice. Notch2tm1.1Ecan mice are osteopenic and have enhanced osteoclastogenesis. Bulk RNA-Seq and gene set enrichment analysis of Notch2tm1.1Ecan BMMs cultured in the presence of macrophage colony stimulating factor (M-CSF) and receptor activator of NF-κB ligand revealed enrichment of genes associated with enhanced cell metabolism, aerobic respiration, and mitochondrial function, all associated with osteoclastogenesis. These pathways were not enhanced in the context of a Hes1 inactivation. Analysis of single cell RNA-Seq data of pooled control and Notch2tm1.1Ecan BMMs treated with M-CSF or M-CSF and receptor activator of NF-κB ligand for 3 days identified 11 well-defined cellular clusters. Pseudotime trajectory analysis indicated a trajectory of clusters expressing genes associated with osteoclast progenitors, osteoclast precursors, and mature cells. There were an increased number of cells expressing gene markers associated with the osteoclast and with an unknown, albeit related, cluster in Notch2tm1.1Ecan than in control BMMs as well as enhanced expression of genes associated with osteoclast progenitors and precursors in Notch2tm1.1Ecan cells. In conclusion, BMM cultures display cellular heterogeneity, and NOTCH2 enhances osteoclastogenesis, increases mitochondrial and metabolic activity of osteoclasts, and affects cell cluster allocation in BMMs.

Notch signaling in adipose tissue macrophages prevents diet-induced inflammation and metabolic dysregulation.

The importance of macrophages in adipose tissue (AT) homeostasis and inflammation is well established. However, the potential cues that regulate their function remain incompletely understood. To bridge this important gap, we sought to characterize novel pathways involved using a mouse model of diet-induced obesity. By performing transcriptomics analysis of AT macrophages (ATMs), we found that late-stage ATMs from high-fat diet mice presented with perturbed Notch signaling accompanied by robust proinflammatory and metabolic changes. To explore the hypothesis that the deregulated Notch pathway contributes to the development of AT inflammation and diet-induced obesity, we employed a genetic approach to abrogate myeloid Notch1 and Notch2 receptors. Our results revealed that the combined loss of Notch1 and Notch2 worsened obesity-related metabolic dysregulation. Body and AT weight gain was higher, blood glucose levels increased and metabolic parameters were substantially worsened in deficient mice fed high-fat diet. Moreover, serum insulin and leptin were elevated as were triglycerides. Molecular analysis of ATMs showed that deletion of Notch receptors escalated inflammation through the induction of an M1-like pro-inflammatory phenotype. Our findings thus support a protective role of myeloid Notch signaling in adipose tissue inflammation and metabolic dysregulation.

DLBCL-associated NOTCH2 mutations escape ubiquitin-dependent degradation and promote chemoresistance.

Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of non-Hodgkin lymphoma. Up to 40% of patients with DLBCL display refractory disease or relapse after standard chemotherapy treatment (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone [R-CHOP]), leading to significant morbidity and mortality. The molecular mechanisms of chemoresistance in DLBCL remain incompletely understood. Using a cullin-really interesting new gene (RING) ligase-based CRISPR-Cas9 library, we identify that inactivation of the E3 ubiquitin ligase KLHL6 promotes DLBCL chemoresistance. Furthermore, proteomic approaches helped identify KLHL6 as a novel master regulator of plasma membrane-associated NOTCH2 via proteasome-dependent degradation. In CHOP-resistant DLBCL tumors, mutations of NOTCH2 result in a protein that escapes the mechanism of ubiquitin-dependent proteolysis, leading to protein stabilization and activation of the oncogenic RAS signaling pathway. Targeting CHOP-resistant DLBCL tumors with the phase 3 clinical trial molecules nirogacestat, a selective γ-secretase inhibitor, and ipatasertib, a pan-AKT inhibitor, synergistically promotes DLBCL destruction. These findings establish the rationale for therapeutic strategies aimed at targeting the oncogenic pathway activated in KLHL6- or NOTCH2-mutated DLBCL.

NOTCH2 Hajdu-Cheney Mutations Escape SCFFBW7-Dependent Proteolysis to Promote Osteoporosis.

Hajdu-Cheney syndrome (HCS), a rare autosomal disorder caused by heterozygous mutations in NOTCH2, is clinically characterized by acro-osteolysis, severe osteoporosis, short stature, neurological symptoms, cardiovascular defects, and polycystic kidneys. Recent studies identified that aberrant NOTCH2 signaling and consequent osteoclast hyperactivity are closely associated with the bone-related disorder pathogenesis, but the exact molecular mechanisms remain unclear. Here, we demonstrate that sustained osteoclast activity is largely due to accumulation of NOTCH2 carrying a truncated C terminus that escapes FBW7-mediated ubiquitination and degradation. Mice with osteoclast-specific Fbw7 ablation revealed osteoporotic phenotypes reminiscent of HCS, due to elevated Notch2 signaling. Importantly, administration of Notch inhibitors in Fbw7 conditional knockout mice alleviated progressive bone resorption. These findings highlight the molecular basis of HCS pathogenesis and provide clinical insights into potential targeted therapeutic strategies for skeletal disorders associated with the aberrant FBW7/NOTCH2 pathway as observed in patients with HCS.

Mutations in MINAR2 encoding membrane integral NOTCH2-associated receptor 2 cause deafness in humans and mice.

Discovery of deafness genes and elucidating their functions have substantially contributed to our understanding of hearing physiology and its pathologies. Here we report on DNA variants in MINAR2, encoding membrane integral NOTCH2-associated receptor 2, in four families underlying autosomal recessive nonsyndromic deafness. Neurologic evaluation of affected individuals at ages ranging from 4 to 80 y old does not show additional abnormalities. MINAR2 is a recently annotated gene with limited functional understanding. We detected three MINAR2 variants, c.144G > A (p.Trp48*), c.412_419delCGGTTTTG (p.Arg138Valfs*10), and c.393G > T, in 13 individuals with congenital- or prelingual-onset severe-to-profound sensorineural hearing loss (HL). The c.393G > T variant is shown to disrupt a splice donor site. We show that Minar2 is expressed in the mouse inner ear, with the protein localizing mainly in the hair cells, spiral ganglia, the spiral limbus, and the stria vascularis. Mice with loss of function of the Minar2 protein (Minar2tm1b/tm1b) present with rapidly progressive sensorineural HL associated with a reduction in outer hair cell stereocilia in the shortest row and degeneration of hair cells at a later age. We conclude that MINAR2 is essential for hearing in humans and mice and its disruption leads to sensorineural HL. Progressive HL observed in mice and in some affected individuals and as well as relative preservation of hair cells provides an opportunity to interfere with HL using genetic therapies.

NOTCH2 sensitizes the chondrocyte to the inflammatory response of tumor necrosis factor α.

Notch regulates the immune and inflammatory response and has been associated with the pathogenesis of osteoarthritis in humans and preclinical models of the disease. Notch2tm1.1Ecan mice harbor a NOTCH2 gain-of-function and are sensitized to osteoarthritis, but the mechanisms have not been explored. We examined the effects of tumor necrosis factor α (TNFα) in chondrocytes from Notch2tm1.1Ecan mice and found that NOTCH2 enhanced the effect of TNFα on Il6 and Il1b expression. Similar results were obtained in cells from a conditional model of NOTCH2 gain-of-function, Notch22.1Ecan mice, and following the expression of the NOTCH2 intracellular domain in vitro. Recombination signal-binding protein for immunoglobulin Kappa J region partners with the NOTCH2 intracellular domain to activate transcription; in the absence of Notch signaling it inhibits transcription, and Rbpj inactivation in chondrocytes resulted in Il6 induction. Although TNFα induced IL6 to a greater extent in the context of NOTCH2 activation, there was a concomitant inhibition of Notch target genes Hes1, Hey1, Hey2, and Heyl. Electrophoretic mobility shift assay demonstrated displacement of recombination signal-binding protein for immunoglobulin Kappa J region from DNA binding sites by TNFα explaining the increased Il6 expression and the concomitant decrease in Notch target genes. NOTCH2 enhanced the effect of TNFα on NF-κB signaling, and RNA-Seq revealed increased expression of pathways associated with inflammation and the phagosome in NOTCH2 overexpressing cells in the absence and presence of TNFα. Collectively, NOTCH2 has important interactions with TNFα resulting in the enhanced expression of Il6 and inflammatory pathways in chondrocytes.

Atomoxetine suppresses radioresistance in glioblastoma via circATIC/miR-520d-5p/Notch2-Hey1 axis.

BACKGROUND: Resistance acquired after radiotherapy is directly related to the failure of various cancer treatments, including GBM. Because the mechanism for overcoming radioresistance has not yet been clearly identified, the development of diagnostic and therapeutic markers to treat radioresistance is necessary. Since increased expression of stemness- and EMT-related markers are reported to be closely correlated with radioresistance, research is underway to develop new drugs targeting these factors. METHODS: To develop an anticancer drug that overcomes radioresistance, a library of drugs already approved by the FDA was used. After treating radioresistant GBM cells with each drug, the expression of stemness- and EMT-related markers was confirmed by qRT-PCR, and as a result, Atomoxetine (ATX) was selected. It was confirmed that radioresistance-induced cell migratory, invasive, sphere formation abilities, and tumor growth using a xenograft mouse model were suppressed upon ATX treatment. Using a miRNA prediction tool, we discovered miR-520d-5p, which targets Notch2 and Hey1, key factors in radioresistance, and discovered circATIC targeting this miRNA, revealing its relationship with ATX. We demonstrated the expression regulation mechanism and signaling mechanism between circATIC, miR-520d-5p, Notch2, and Hey1 factors using a luciferase reporter assay. In addition, the results at the cellular level were clinically verified by confirming the correlation between radiation, miR-520d-5p, and circATIC using patient plasma by qRT-PCR. RESULTS: ATX showed potential as a treatment for radioresistance by suppressing the malignant phenotype by regulating the circATIC/miR-520d-5p/Notch2-Hey1 signaling mechanism in vitro and in vivo using radioresistant GBM cells. CONCLUSIONS: This study revealed that ATX suppresses radioresistance through the circATIC/miR-520d-5p/Notch2-Hey1 signaling pathway. These results showed the potential of ATX as a new drug that can overcome radioresistance, a major challenge in cancer treatment, and the signaling factors identified in this mechanism suggest the possibility of use as potential targets for the diagnosis and treatment of radioresistance.

High expression of NOTCH2 in gastric adenocarcinoma: A novel early diagnostic target.

BACKGROUND AND AIM: NOTCH2 is overexpressed in gastric cancer (GC), and its enhanced activity is significantly correlated with worse tumor characteristics. We aim to analyze the clinicopathologic correlation between NOTCH2 and the molecular typing of GC by immunohistochemistry and by transcriptional sequencing. METHODS: In this immunohistochemical study, we detected NOTCH2, EBER, P53, HER2, MLH1, MSH2, PMS2, and MSH6 and evaluated the association of NOTCH2 with clinical and histopathological features in a large single-institutional series of gastric adenocarcinomas (n = 488). The correlation was also investigated between immunohistochemical results and survival outcomes. RESULTS: High NOTCH2 expression (2+/3+) was found in 139/488 (27.5%) samples analyzed. NOTCH2 expression was correlated with early stage T1 (P < 0.0001), GC in the fundus (P = 0.0364), and positive P53 status (P = 0.0019). We did not find an association between NOTCH2 and HER2, microsatellite instability, EBER, and overall survival. Through RNA sequencing, it was revealed that NOTCH2 plays an important biological function in the pathogenesis and development of GC. CONCLUSIONS: Our findings suggested that NOTCH2 may be a potential diagnostic target for GC due to the fact that its high expression is closely associated with the early stages of cancer.

Differential Response of Human Dendritic Cells upon Stimulation with Encapsulated or Non-Encapsulated Isogenic Strains of Porphyromonas gingivalis.

During periodontitis, the extracellular capsule of Porphyromonas gingivalis favors alveolar bone loss by inducing Th1 and Th17 patterns of lymphocyte response in the infected periodontium. Dendritic cells recognize bacterial antigens and present them to T lymphocytes, defining their activation and polarization. Thus, dendritic cells could be involved in the Th1 and Th17 response induced against the P. gingivalis capsule. Herein, monocyte-derived dendritic cells were obtained from healthy individuals and then stimulated with different encapsulated strains of P. gingivalis or two non-encapsulated isogenic mutants. Dendritic cell differentiation and maturation were analyzed by flow cytometry. The mRNA expression levels for distinct Th1-, Th17-, or T-regulatory-related cytokines and transcription factors, as well as TLR2 and TLR4, were assessed by qPCR. In addition, the production of IL-1ß, IL-6, IL-23, and TNF-α was analyzed by ELISA. The encapsulated strains and non-encapsulated mutants of P. gingivalis induced dendritic cell maturation to a similar extent; however, the pattern of dendritic cell response was different. In particular, the encapsulated strains of P. gingivalis induced higher expression of IRF4 and NOTCH2 and production of IL-1ß, IL-6, IL-23, and TNF-α compared with the non-encapsulated mutants, and thus, they showed an increased capacity to trigger Th1 and Th17-type responses in human dendritic cells.

[Relationships between Cxcl12, Tweak, Notch1, and Yap mRNA Expression Levels in Molecular Mechanisms of Liver Fibrogenesis].

Current data on the molecular mechanisms of liver fibrosis and cirrhosis fail to fully explain all stages of their development. Interactions between individual genes and signaling pathways are known to play an important role in their functions. However, data on their relationships are insufficient and often contradictory. For the first time, mRNA expression of Notch1, Notch2, Yap1, Tweak (Tnfsf12), Fn14 (Tnfrsf12a), Ang, Vegfa, Cxcl12 (Sdf), Nos2, and Mmp-9 was studied in detail at several stages of thioacetamide-induced liver fibrosis in Wistar rats. A factor analysis isolated three factors, which combined highly correlated target genes. The first factor included four genes: Cxcl12 (r = 0.829, p < 0.05), Tweak (r = 0.841, p < 0.05), Notch1 (r = 0.848, p < 0.05), and Yap1 (r = 0.921, p < 0.05). The second factor described the correlation between Mmp-9 (r = 0.791, p < 0.05) and Notch2 (r = 0.836, p < 0.05). The third factor included Ang (r = 0.748, p < 0.05) and Vegfa (r = 0.679, p < 0.05). The Nos2 and Fn14 genes were not included in any of the factors. The gene grouping by mRNA expression levels made it possible to assume a pathogenetic relationship between their products in the development of fibrotic changes due to liver toxicity.

[Clinical and genetic analysis of a patient with Neuronal intranuclear inclusion body disease characterized by cortical enhancement in the posterior brain region].

OBJECTIVE: To explore the clinical, imaging, and genetic characteristics of an adult patient with sporadic Neuronal intranuclear inclusion disease (NIID). METHODS: A patient who had visited the First People's Hospital of Chenzhou on August 6, 2023 was selected as the study subject. Results of clinical examination, neuroimaging, and genetic testing were retrospectively analyzed along with a literature review. The number of GGC trinucleotide repeats in the 5'-untranslated region of the NOTCH2NLC gene was determined by GC-PCR. RESULTS: The patient had presented with episodic encephalopathy, with enhanced magnetic resonance imaging showing enhancement features of the posterior cerebral cortex during the period of acute episode. Genetic testing revealed an increased number of GGC repeats (n = 97) in the 5'- untranslated region of the NOTCH2NLC gene, which confirmed the diagnosis of NIID. CONCLUSION: Clinical attention should be paid to the enhanced MRI findings of patients with adult-onset NIID, for whom posterior cortical enhancement may be characteristic manifestation during the acute phase of encephalopathy-like episode.

BAFF promotes heightened BCR responsiveness and manifestations of chronic GVHD after allogeneic stem cell transplantation.

Patients with chronic graft-versus-host disease (cGVHD) have increased B cell-activating factor (BAFF) levels, but whether BAFF promotes disease after allogeneic bone marrow transplantation (allo-BMT) remains unknown. In a major histocompatibility complex-mismatched model with cGVHD-like manifestations, we first examined B-lymphopenic µMT allo-BMT recipients and found that increased BAFF levels in cGVHD mice were not merely a reflection of B-cell number. Mice that later developed cGVHD had significantly increased numbers of recipient fibroblastic reticular cells with higher BAFF transcript levels. Increased BAFF production by donor cells also likely contributed to cGVHD, because BAFF transcript in CD4+ T cells from diseased mice and patients was increased. cGVHD manifestations in mice were associated with high BAFF/B-cell ratios and persistence of B-cell receptor (BCR)-activated B cells in peripheral blood and lesional tissue. By employing BAFF transgenic (Tg) mice donor cells, we addressed whether high BAFF contributed to BCR activation in cGVHD. BAFF increased NOTCH2 expression on B cells, augmenting BCR responsiveness to surrogate antigen and NOTCH ligand. BAFF Tg B cells had significantly increased protein levels of the proximal BCR signaling molecule SYK, and high SYK protein was maintained by BAFF after in vitro BCR activation or when alloantigen was present in vivo. Using T cell-depleted (BM only) BAFF Tg donors, we found that BAFF promoted cGVHD manifestations, circulating GL7+ B cells, and alloantibody production. We demonstrate that pathologic production of BAFF promotes an altered B-cell compartment and augments BCR responsiveness. Our findings compel studies of therapeutic targeting of BAFF and BCR pathways in patients with cGVHD.

Hajdu-Cheney syndrome with atypical cardiovascular abnormalities.

Hajdu-Cheney syndrome is an ultra-rare autosomal dominant disorder caused by a heterozygous variant in NOTCH2 gene. Characteristic features include osteolysis, distinct facial appearance, skull deformity, joint laxity, osteoporosis, and short stature. Associated abnormalities are congenital heart disease, congenital defects of the kidney, and neurological problems. Here, we present the first reported case of an African child with a variant in NOTCH2 gene and features of Hajdu-Cheney syndrome in whom we detected a congenital heart defect that has not been previously reported in association with the syndrome. To appropriately characterize this disease and document correct proportion of cardiovascular malformation associations, echocardiography is recommended for all cases of Hajdu Cheney syndrome.

PIK3R3 Missense and NOTCH2 Synonymous Single Nucleotide Polymorphisms Are Associated with Liver Cancer.

BACKGROUND: Single nucleotide polymorphism (SNP) of candidate genes also affects the occurrence and prognosis of liver cancer. We mainly explored the effects of PIK3R3 and NOTCH2 polymorphisms on liver cancer risk among Chinese people. METHODS: Four SNPs (rs785468, rs785467, rs3795666, and rs17024525 in PIK3R3 and NOTCH2) from 709 liver cancer patients and 700 healthy controls were genotyped using the Agena MassARRAY system. The correlation between SNPs and liver cancer risk was evaluated using logistic regression analysis. The SNP-SNP interactions were conducted by the multifactor dimensionality reduction method. RESULTS: The results revealed that PIK3R3-rs785467 reduced the likelihood of liver cancer among Chinese Han people (p < 0.05). In addition, PIK3R3-rs785467 decreased the susceptibility to liver cancer in different populations (females, non-smokers, and age >55 years, p < 0.05). NOTCH2-rs3795666 reduced the susceptibility to liver cancer among males, drinkers, and patients aged >55 years (p < 0.05). CONCLUSIONS: Our results demonstrate that PIK3R3-rs785476 and NOTCH2-rs3795666 polymorphisms are responsible for decreasing the susceptibility of liver cancer development in the Chinese Han population.

Clinical significance of Notch pathway-associated microRNA-107 in pancreatic ductal adenocarcinoma.

Background & aim: MicroRNAs associated with the Notch pathway play a critical role in the progression of pancreatic carcinoma. Our aim was to study the clinical significance of miR-107 and NOTCH2 in pancreatic ductal adenocarcinoma (PDAC). Methods: The circulating miR-107 levels in PDAC and controls were determined by qPCR. NOTCH2 protein (target) expression in tissue of PDAC, periampullary carcinoma, chronic pancreatitis and normal pancreatic tissue was assessed by immunohistochemistry. Results: The circulating miR-107 levels were found to be significantly reduced in PDAC as compared with controls. Additionally, NOTCH2 protein expression was higher in PDAC tissue as compared with controls and was clinically associated with metastasis. Conclusion: Our findings demonstrate the utility of circulating miR-107 as a potential differentiating marker in PDAC.

Coordinated modification in expression levels of HSPA1A/B, DGKH, and NOTCH2 in Parkinson's patients' blood and substantia nigra as a diagnostic sign: the transcriptomes' relationship.

BACKGROUND: Diagnosis of Parkinson's disease (PD) is associated with a vast number of challenges. This study aimed to assess the overlap of PD patients' transcriptomes in the substantia nigra (SN) with peripheral blood mononuclear cells (PBMCs) to discover potential biomarkers for diagnosis. METHODS: GEO data were used to select genes with significant changes in expression level in the SN region and eligible studies. Also, transcriptome data related to blood of PD patients with other neurodegenerative diseases (ND) was considered. Differential expression genes between PD and control were evaluated in the SN and blood, and RT-qPCR was applied to validate the findings. RESULTS: At the expression level, no significant similarity in long non-coding RNA was found between the patients' SN and blood. While in silico results revealed 16 common mRNAs in SN and blood with significant expression levels. Among all overexpressed mRNAs, HSPA1A/B expression level had the highest expression difference between control and PD samples. Moreover, DGKH had the highest score of down-regulated genes in both blood and SN. The NOTCH pathway had the highest score pathway among up-regulated pathways, and the expression levels of NOTCH2, H4C8, and H2BC21 associated with this pathway had the most ability to separate the control and PD populations. Furthermore, RT-qPCR results revealed that HSPA1A/B, NOTCH2, and H4C8 were overexpressed in PD PBMCs, while DGKH expression levels were lower compared to controls. CONCLUSION: Our findings indicate that expression levels of HSPA1A/B, DGKH, and NOTCH2 could be applied as candidate biomarkers to diagnose PD patients in the SN region and PBMCs.