Faculty of Psychology and Neuroscience, Maastricht University, 6229 ER Maastricht, The Netherlands.
Neuroscience Center, Helsinki Institute of Life Science (HiLIFE), University of Helsinki, 00100 Helsinki, Finland.
Int J Mol Sci. 2022 Sep 6;23(18):10249. doi: 10.3390/ijms231810249.
The activation of tropomyosin receptor kinase B (TrkB), the receptor of brain-derived neurotrophic factor (BDNF), plays a key role in induced juvenile-like plasticity (iPlasticity), which allows restructuring of neural networks in adulthood. Optically activatable TrkB (optoTrkB) can temporarily and spatially evoke iPlasticity, and recently, optoTrkB (E281A) was developed as a variant that is highly sensitive to light stimulation while having lower basal activity compared to the original optoTrkB. In this study, we validate optoTrkB (E281A) activated in alpha calcium/calmodulin-dependent protein kinase type II positive (CKII) pyramidal neurons or parvalbumin-positive (PV) interneurons in the mouse visual cortex by immunohistochemistry. OptoTrkB (E281A) was activated in PV interneurons and CKII pyramidal neurons with blue light (488 nm) through the intact skull and fur, and through a transparent skull, respectively. LED light stimulation significantly increased the intensity of phosphorylated ERK and CREB even through intact skull and fur. These findings indicate that the highly sensitive optoTrkB (E281A) can be used in iPlasticity studies of both inhibitory and excitatory neurons, with flexible stimulation protocols in behavioural studies.
脑源性神经营养因子（BDNF）受体——原肌球蛋白受体激酶 B（TrkB）的激活在诱导性幼年样可塑性（iPlasticity）中起着关键作用，这种可塑性允许成年期神经网络的重新构建。光可激活的 TrkB（optoTrkB）可以暂时和空间地引发 iPlasticity，最近，开发了光可激活的 TrkB（E281A）作为一种变体，与原始的 optoTrkB 相比，它对光刺激高度敏感，而基础活性较低。在这项研究中，我们通过免疫组织化学验证了 optoTrkB（E281A）在小鼠视觉皮层中 alpha 钙/钙调蛋白依赖性蛋白激酶 II 阳性（CKII）锥体神经元或 Parvalbumin 阳性（PV）中间神经元中的激活。optoTrkB（E281A）可以通过完整的头骨和皮毛，以及通过透明头骨，用蓝光（488nm）激活 PV 中间神经元和 CKII 锥体神经元。LED 光刺激即使通过完整的头骨和皮毛也能显著增加磷酸化 ERK 和 CREB 的强度。这些发现表明，高敏感的 optoTrkB（E281A）可用于抑制性和兴奋性神经元的 iPlasticity 研究，并在行为研究中具有灵活的刺激方案。
