Variants ofWNT7AandGPR124are associated with hemorrhagic transformation following intravenous thrombolysis in ischemic stroke
CNS NEUROSCIENCE & THERAPEUTICS
Authors: Ta, Song; Rong, Xianfang; Guo, Zhen-Ni; Jin, Hang; Zhang, Peng; Li, Fenge; Li, Zhihuan; Lin, Lilong; Zheng, Chenqing; Gu, Qingquan; Zhang, Yuan; Liu, Wenlan; Yang, Yi; Chang, Junlei
Abstract
Aims The canonical Wnt signaling pathway plays an essential role in blood-brain barrier integrity and intracerebral hemorrhage in preclinical stroke models. Here, we sought to explore the association between canonical Wnt signaling and hemorrhagic transformation (HT) following intravenous thrombolysis (IVT) in acute ischemic stroke (AIS) patients as well as to determine the underlying cellular mechanisms. Methods 355 consecutive AIS patients receiving IVT were included. Blood samples were collected on admission, and HT was detected at 24 hours after IVT. 117 single-nucleotide polymorphisms (SNPs) of 28 Wnt signaling genes and exon sequences of 4 core cerebrovascular Wnt signaling components (GPR124,RECK,FZD4,andCTNNB1) were determined using a customized sequencing chip. The impact of identified genetic variants was further studied in HEK 293T cells using cellular and biochemical assays. Results During the study period, 80 patients experienced HT with 27 parenchymal hematoma (PH). Compared to the non-PH patients,WNT7ASNPs (rs2163910,P = .001, OR 2.727; rs1124480,P = .002, OR 2.404) andGPR124SNPs (rs61738775,P = .012, OR 4.883; rs146016051,P < .001, OR 7.607; rs75336000,P = .044, OR 2.503) were selectively enriched in the PH patients. Interestingly, a missense variant ofGPR124(rs75336000, c.3587G>A) identified in the PH patients resulted in a single amino acid alteration (p.Cys1196Tyr) in the intracellular domain of GPR124. This variant substantially reduced the activity of WNT7B-induced canonical Wnt signaling by decreasing the ability of GPR124 to recruit cytoplasmic DVL1 to the cellular membrane. Conclusion Variants ofWNT7AandGPR124are associated with increased risk of PH in patients with AIS after intravenous thrombolysis, likely through regulating the activity of canonical Wnt signaling.
Comprehensive Wnt-related gene expression during cochlear duct development in chicken
JOURNAL OF COMPARATIVE NEUROLOGY
Authors: Sienknecht, Ulrike J.; Fekete, Donna M.
Abstract
The avian cochlear duct houses both a vestibular and auditory sensory organ (the lagena macula and basilar papilla, respectively), which each have a distinct structure and function. Comparative mRNA in situ hybridization mapping conducted over the time course of chicken cochlear duct development reveals that Wnt-related gene expression is concomitant with various developmental processes such as regionalization, convergent extension of the cochlear duct, cell fate specification, synaptogenesis, and the establishment of planar cell polarity. Wnts mostly originate from nonsensory tissue domains, whereas the sensory primordia preferentially transcribe Frizzled receptors, suggesting that paracrine Wnt signaling predominates in the cochlear duct. Superimposed over this is the strong expression of two secreted Frizzled-related Wnt inhibitors that tend to show complementary expression patterns. Frzb (SFRP3) is confined to the nonsensory cochlear duct and the lagena macula, whereas SFRP2 is maintained in the basilar papilla along with Fzd10 and Wnt7b. Flanking the basilar papilla are Wnt7a, Wnt9a, Wnt11, and SFRP2 on the neural side and Wnt5a, Wnt5b, and Wnt7a on the abneural side. The lateral nonsensory cochlear duct continuously expresses Frzb and temporarily expresses Wnt6 and SFRP1. Characteristic for the entire lagena is the expression of Frzb; in the lagena macula are Fzd1, Fzd7, and Wnt7b, and in the nonsensory tissues are Wnt4 and Wnt5a. Auditory hair cells preferentially express Fzd2 and Fzd9, whereas the main receptors expressed in vestibular hair cells are Fzd1 and Fzd7, in addition to Fzd2 and Fzd9.