FoxP2 directly regulates the reelin receptor VLDLR developmentally and by singing.

Mutations of the transcription factor FOXP2 cause a severe speech and language disorder. In songbirds, FoxP2 is expressed in the medium spiny neurons (MSNs) of the avian basal ganglia song nucleus, Area X, which is crucial for song learning and adult song performance. Experimental downregulation of FoxP2 in Area X affects spine formation, prevents neuronal plasticity induced by social context and impairs song learning. Direct target genes of FoxP2 relevant for song learning and song production are unknown. Here we show that a lentivirally mediated FoxP2 knockdown in Area X of zebra finches downregulates the expression of VLDLR, one of the two reelin receptors. Zebra finch FoxP2 binds to the promoter of VLDLR and activates it, establishing VLDLR as a direct FoxP2 target. Consistent with these findings, VLDLR expression is co-regulated with FoxP2 as a consequence of adult singing and during song learning. We also demonstrate that knockdown of FoxP2 affects glutamatergic transmission at the corticostriatal MSN synapse. These data raise the possibility that the regulatory relationship between FoxP2 and VLDLR guides structural plasticity towards the subset of FoxP2-positive MSNs in an activity dependent manner via the reelin pathway.

The porcine chloride channel calcium-activated family member pCLCA4a mirrors lung expression of the human hCLCA4.

Pig models of cystic fibrosis (CF) have recently been established that are expected to mimic the human disease closer than mouse models do. The human CLCA (originally named chloride channels, calcium-activated) member hCLCA4 is considered a potential modifier of disease severity in CF, but its murine ortholog, mCLCA6, is not expressed in the mouse lung. Here, we have characterized the genomic structure, protein processing, and tissue expression patterns of the porcine ortholog to hCLCA4, pCLCA4a. The genomic structure and cellular protein processing of pCLCA4a were found to closely mirror those of hCLCA4 and mCLCA6. Similar to human lung, pCLCA4a mRNA was strongly expressed in porcine lungs, and the pCLCA4a protein was immunohistochemically detected on the apical membranes of tracheal and bronchial epithelial cells. This stands in sharp contrast to mouse mCLCA6, which has been detected exclusively in intestinal epithelia but not the murine lung. The results may add to the understanding of species-specific differences in the CF phenotype and support the notion that the CF pig model may be more suitable than murine models to study the role of hCLCA4.

Arc/Arg3.1 is essential for the consolidation of synaptic plasticity and memories.

Arc/Arg3.1 is robustly induced by plasticity-producing stimulation and specifically targeted to stimulated synaptic areas. To investigate the role of Arc/Arg3.1 in synaptic plasticity and learning and memory, we generated Arc/Arg3.1 knockout mice. These animals fail to form long-lasting memories for implicit and explicit learning tasks, despite intact short-term memory. Moreover, they exhibit a biphasic alteration of hippocampal long-term potentiation in the dentate gyrus and area CA1 with an enhanced early and absent late phase. In addition, long-term depression is significantly impaired. Together, these results demonstrate a critical role for Arc/Arg3.1 in the consolidation of enduring synaptic plasticity and memory storage.

Collagen degradation in a murine myocarditis model: relevance of matrix metalloproteinase in association with inflammatory induction.

OBJECTIVE: Myocardial collagen degradation is regulated by matrix metalloproteinases (MMPs) and tissue inhibitors of matrix metalloproteinase (TIMPs). The possible relevance of MMPs in association with the inflammatory induction was investigated in a murine coxsackievirus B3 myocarditis model. METHODS: Hearts from viral infected and sham-infected BALB/c mice were analyzed by semi-quantitative RT-PCR, picrosirius red staining, Western blot analysis, and immunohistochemistry. RESULTS: In viral infected mice, both mRNA and protein abundance for collagen type I remained unaltered. In addition, picrosirius red staining showed the unchanged total collagen content. However, degraded soluble fraction of collagen type I protein was increased. Moreover, the mRNA abundance for MMP-3 and MMP-9 was upregulated, whereas the mRNAs for TIMP-1 and TIMP-4 were downregulated, respectively. The upregulation of MMP-3/MMP-9 and downregulation of TIMP-4 were confirmed at the protein level, and were associated with significantly increased mRNA levels of interleukin 1beta, tumor necrosis factor-alpha, transforming growth factor-beta1 and interleukin-4. CONCLUSION: The increment of MMPs in the absence of counterbalance by TIMPs may lead to a functional defect of the myocardial collagen network by posttranslational mechanisms. This may contribute significantly to the development of left ventricular dysfunction in murine viral myocarditis. The inflammatory response with induction of cytokines may mediate the dysregulation of the myocardial MMP/TIMP systems.