Canonical versus non-canonical transsynaptic signaling of neuroligin 3 tunes development of sociality in mice

社会性の発達を調節する新たな機構を発見. 京都大学プレスリリース. 2021-03-26.Neuroligin 3 (NLGN3) and neurexins (NRXNs) constitute a canonical transsynaptic cell-adhesion pair, which has been implicated in autism. In autism spectrum disorder (ASD) development of sociality can be impaired. However, the molecular mechanism underlying NLGN3-mediated social development is unclear. Here, we identify non-canonical interactions between NLGN3 and protein tyrosine phosphatase δ (PTPδ) splice variants, competing with NRXN binding. NLGN3-PTPδ complex structure revealed a splicing-dependent interaction mode and competition mechanism between PTPδ and NRXNs. Mice carrying a NLGN3 mutation that selectively impairs NLGN3-NRXN interaction show increased sociability, whereas mice where the NLGN3-PTPδ interaction is impaired exhibit impaired social behavior and enhanced motor learning, with imbalance in excitatory/inhibitory synaptic protein expressions, as reported in the Nlgn3 R451C autism model. At neuronal level, the autism-related Nlgn3 R451C mutation causes selective impairment in the non-canonical pathway. Our findings suggest that canonical and non-canonical NLGN3 pathways compete and regulate the development of sociality

The diagnostic performance of a novel ELISA for human CTP (Cochlin-tomoprotein) to detect perilymph leakage.

Perilymphatic fistula is defined as an abnormal communication between the perilymph-filled space and the middle ear, or cranial spaces. The manifestations include a broad spectrum of neuro-otological symptoms such as hearing loss, vertigo/dizziness, disequilibrium, aural fullness, tinnitus, and cognitive dysfunction. By sealing the fistula, perilymphatic fistula is a surgically correctable disease. Also, appropriate recognition and treatment of perilymphatic fistula can improve a patient's condition and hence the quality of life. However, the difficulty in making a definitive diagnosis due to the lack of an appropriate biomarker to detect perilymph leakage has caused a long-standing debate regarding its management. We have reported a clinical test for the diagnosis of perilymphatic fistula by detecting a perilymph specific protein, Cochlin-tomoprotein, as a diagnostic marker using a western blot. The aim of this study is to establish an ELISA-based human Cochlin-tomoprotein detection test and to evaluate its diagnostic accuracy in clinical subjects. The results of ELISA showed good dilution reproducibility. The mean concentration was 49.7±9.4 of 10 perilymph samples. The ROC curve in differentiating the perilymph leakage condition from the normal middle ear was significant (P < 0.001) with an area under the curve (AUC) of 0.918 (95% CI 0.824-0.100). We defined the diagnostic criteria as follows: CTP<0.4 negative; 0.4≦CTP<0.8 intermediate; 0.8≦CTP(ng/ml) positive in the clinical usage of the hCTP ELISA, and sensitivity and specificity were 86.4% and 100%, respectively. We further tested the expression specificity of the Cochlin-tomoprotein by testing blood and CSF samples. The concentration was below the detection limit (0.2 ng/ml) in 38 of the 40 blood, and 14 of the 19 CSF samples. We report the accuracy of this test for the diagnosis of perilymphatic fistula. Using ELISA, we can improve the throughput of the test. Furthermore, it is useful for a large-scale study to characterize the clinical picture and delineate the management of this medical condition

Receiver-operating characteristic (ROC) plots.

<p>A receiver operating characteristic (ROC) curve constructed from CTP in differentiating perilymph leakage conditions (Sample C) from normal middle ear conditions (Samples A and D) was significant (P < 0.001) with an area under the curve (AUC) of 0.918 (Fig 3). We then identified the optimal cutoff values using a ROC analysis with Youden’s index for CTP, and the analysis indicated no.1 = 0.740 ng/ml, (Index 0.864), and no.2 = 0.405 ng/ml, (Index 0.842). We defined the diagnostic criteria as follows: CTP<0.4 negative; 0.4≦CTP<0.8 intermediate; and 0.8≦CTP positive.</p

Summaries of the number of negative, intermediate, and positive CTP cases in each group of middle ear lavage samples.

<p>Summaries of the number of negative, intermediate, and positive CTP cases in each group of middle ear lavage samples.</p

Scatter gram of CTP concentration of each group of samples.

<p>Samples A, B and C were collected from 22 cases who had undergone cochlear implant surgery. <i>Sample A</i>: MEL was collected as soon as entering the middle ear without performing any manipulation to the cochlea and before opening the round window membrane. <i>Sample B</i>: MEL was collected just after drilling the round window bony overhang. <i>Sample C</i>: MEL was collected after electrode insertion and sealing the round window with connective tissue. In addition to the above, we have included an additional 24 cases that had undergone exploratory tympanotomy for conductive hearing loss. <i>Sample D</i>: MEL was collected as soon as entering the middle ear without performing any manipulation to the ossicles. The CTP concentration of each sample was plotted and the median concentration was represented using a bar. There were statistically significant differences between sample A and C (P<0.001), B and C (P<0.001), C and D (P<0.001). No statistical differences were detected between sample A and B (P>0.99), A and D (P>0.99), B and D (P>0.99) (based on the Kruskal-Wallis test and Dunn’s multiple comparison test). In sample A, B and D, no samples contained a CTP concentration of more than 0.8. Whereas in sample C, 19 samples (86.4%) were more than 0.8. (data shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0191498#pone.0191498.t001" target="_blank">Table 1A</a>).</p