Association of NOTCH3 Gene Polymorphisms with Ischemic Stroke and its Subtypes: A Meta-Analysis.

Background and objectives: NOTCH3 gene variations play a significant role in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). However, the role of NOTCH3 gene polymorphisms in the risk of ischemic stroke, and its subtypes such as atherothrombotic or lacunar strokes, remains unclear. Aims: Hence, we carried out a meta-analysis to examine whether the NOTCH3 rs1043994, rs1044009 and rs3815188 polymorphisms are associated with ischemic stroke and its major subtypes. Materials and Methods: All relevant studies were systematically screened and meta-analyzed using Review Manager (Revman) version 5.3. The strength of the association between NOTCH3 polymorphisms and ischemic stroke risk and its subtypes were measured as odds ratios and 95% confidence intervals, under different genetic models. Results: A total of ten studies were identified, five of which considered NOTCH3 rs1043994 (2077 cases/2147 controls), five of which considered NOTCH3 rs1044009 (2315 cases/3053 controls), and nine of which considered NOTCH3 rs3815188 (2819 cases/2769 controls). These studies were meta-analyzed for their association with ischemic stroke risk. Four studies (874 cases/2002 controls) of the NOTCH3 rs3815188 polymorphism and three studies of the NOTCH3 rs1043994 (643 cases/1552 controls) polymorphism were meta-analyzed for lacunar stroke risk. Three studies (1013 cases/1972 controls) of the NOTCH3 rs3815188 polymorphism were meta-analyzed for atherothrombotic stroke risk. The meta-analysis results showed a lack of association between all of the studied polymorphisms and the risk of ischemic stroke and its major subtypes (i.e., atherothrombotic and lacunar). Conclusions: NOTCH3 polymorphisms are not significantly associated with the risk of ischemic stroke and its subtypes (p < 0.05).

Aberrant Regulation of Notch3 Signaling Pathway in Polycystic Kidney Disease.

Polycystic kidney disease (PKD) is a genetic disorder characterized by fluid-filled cysts in the kidney and liver that ultimately leads to end-stage renal disease. Currently there is no globally approved therapy for PKD. The Notch signaling pathway regulates cellular processes such as proliferation and de-differentiation, which are cellular hallmarks of PKD. Thus we hypothesized that the Notch pathway plays a critical role in PKD. Evaluation of protein expression of Notch signaling components in kidneys of Autosomal Recessive PKD (ARPKD) and Autosomal Dominant PKD (ADPKD) mouse models and of ADPKD patients revealed that Notch pathway members, particularly Notch3, were consistently upregulated or activated in cyst-lining epithelial cells. Notch3 expression correlated with rapidly growing cysts and co-localized with the proliferation marker, PCNA. Importantly, Notch inhibition significantly decreased forskolin-induced Notch3 activation and proliferation of primary human ADPKD cells, and significantly reduced cyst formation and growth of human ADPKD cells cultured in collagen gels. Thus our data indicate that Notch3 is aberrantly activated and facilitates epithelial cell proliferation in PKD, and that inhibition of Notch signaling may prevent cyst formation and growth.

Expression Profile of NOTCH3 in Mouse Spermatogonia.

Stable and sustainable spermatogenesis is supported by the strict regulation of self-renewal and differentiation of spermatogonial stem cells (SSC), which are a rare population of undifferentiated spermatogonia. It has been revealed that some signaling factors regulate the self-renewal of SSC; however, the molecular mechanism of SSC maintenance is still not completely understood. Notch signaling is an evolutionarily conserved juxtacrine signaling that plays important roles in the cell fate determination of various tissue stem cells. Recently, analyses of loss- and gain-of-function suggested that Notch signaling was necessary for normal spermatogenesis. However, the expression of Notch signal components in spermatogonia is still unclear. Here, we analyzed the distribution of NOTCH3-expressing spermatogonia and the target genes. Double immunostaining with differentiation markers revealed that NOTCH3 was expressed in some undifferentiated and differentiated spermatogonia in mouse testes. To define the target gene of Notch3 signaling in spermatogonia, we analyzed the mRNA expression pattern of Hes and Hey family genes during testis development. Hes1 abundance was decreased during testis development, suggesting that spermatogonia may express Hes1. Immunohistochemical analysis showed that HES1 was expressed in prepubertal spermatogonia, whereas it was expressed predominantly in adult Sertoli cells and weakly in adult spermatogonia. Furthermore, NOTCH3-HES1 double-positive spermatogonia were in pup and adult testes. These results suggest that Notch3 signaling in spermatogonia could promote Hes1 expression.

Serum amyloid P component: A novel potential player in vessel degeneration in CADASIL.

In cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), granular osmiophilic material (GOM) may play some roles in inducing cerebrovascular events. To elucidate the pathogenesis of CADASIL, we used laser microdissection and liquid chromatography-tandem mass spectrometry to analyze cerebrovascular lesions of patients with CADASIL for GOM. The analyses detected serum amyloid P component (SAP), annexin A2, and periostin as the proteins with the largest increase in the samples, which also demonstrated NOTCH3. For the three proteins, anti-human SAP antibody had the strongest reaction in the lesions where the anti-human NOTCH3 antibody showed positive staining. Moreover, immunofluorescence staining with the two antibodies clearly showed co-localization of SAP and NOTCH3. mRNA analyses indicated no positive SAP expression in the brain materials, which suggested that the source of SAP found in the GOM was only the liver. A solid phase enzyme-linked immunosorbent assay confirmed the binding of SAP with NOTCH3. Serum SAP concentrations were neither up-regulated nor down-regulated in CADASIL patients, when compared with those in control subjects. SAP may play an important role in GOM formation although precise mechanisms remain to be elucidated.