Agrin-Lrp4 pathway in hippocampal astrocytes restrains development of temporal lobe epilepsy through adenosine signaling.

BACKGROUND: Human patients often experience an episode of serious seizure activity, such as status epilepticus (SE), prior to the onset of temporal lobe epilepsy (TLE), suggesting that SE can trigger the development of epilepsy. Yet, the underlying mechanisms are not fully understood. The low-density lipoprotein receptor related protein (Lrp4), a receptor for proteoglycan-agrin, has been indicated to modulate seizure susceptibility. However, whether agrin-Lrp4 pathway also plays a role in the development of SE-induced TLE is not clear. METHODS: Lrp4f/f mice were crossed with hGFAP-Cre and Nex-Cre mice to generate brain conditional Lrp4 knockout mice (hGFAP-Lrp4-/-) and pyramidal neuron specific knockout mice (Nex-Lrp4-/-). Lrp4 was specifically knocked down in hippocampal astrocytes by injecting AAV virus carrying hGFAP-Cre into the hippocampus. The effects of agrin-Lrp4 pathway on the development of SE-induced TLE were evaluated on the chronic seizure model generated by injecting kainic acid (KA) into the amygdala. The spontaneous recurrent seizures (SRS) in mice were video monitored. RESULTS: We found that Lrp4 deletion from the brain but not from the pyramidal neurons elevated the seizure threshold and reduced SRS numbers, with no change in the stage or duration of SRS. More importantly, knockdown of Lrp4 in the hippocampal astrocytes after SE induction decreased SRS numbers. In accord, direct injection of agrin into the lateral ventricle of control mice but not mice with Lrp4 deletion in hippocampal astrocytes also increased the SRS numbers. These results indicate a promoting effect of agrin-Lrp4 signaling in hippocampal astrocytes on the development of SE-induced TLE. Last, we observed that knockdown of Lrp4 in hippocampal astrocytes increased the extracellular adenosine levels in the hippocampus 2 weeks after SE induction. Blockade of adenosine A1 receptor in the hippocampus by DPCPX after SE induction diminished the effects of Lrp4 on the development of SE-induced TLE. CONCLUSION: These results demonstrate a promoting role of agrin-Lrp4 signaling in hippocampal astrocytes in the development of SE-induced development of epilepsy through elevating adenosine levels. Targeting agrin-Lrp4 signaling may serve as a potential therapeutic intervention strategy to treat TLE.

NRG1-ErbB4 signaling in the medial amygdala controls mating motivation in adult male mice.

Motivation-driven mating is a basic affair for the maintenance of species. However, the underlying molecular mechanisms that control mating motivation are not fully understood. Here, we report that NRG1-ErbB4 signaling in the medial amygdala (MeA) is pivotal in regulating mating motivation. NRG1 expression in the MeA negatively correlates with the mating motivation levels in adult male mice. Local injection and knockdown of MeA NRG1 reduce and promote mating motivation, respectively. Consistently, knockdown of MeA ErbB4, a major receptor for NRG1, and genetic inactivation of its kinase both promote mating motivation. ErbB4 deletion decreases neuronal excitability, whereas chemogenetic manipulations of ErbB4-positive neuronal activities bidirectionally modulate mating motivation. We also identify that the effects of NRG1-ErbB4 signaling on neuronal excitability and mating motivation rely on hyperpolarization-activated cyclic nucleotide-gated channel 3. This study reveals a critical molecular mechanism for regulating mating motivation in adult male mice.

Probiotics-Fermented Grifola frondosa Total Active Components: Better Antioxidation and Microflora Regulation for Alleviating Alcoholic Liver Damage in Mice.

Alcoholic liver damage is caused by long-term drinking, and it further develops into alcoholic liver diseases. In this study, we prepared a probiotic fermentation product of Grifola frondosa total active components (PFGF) by fermentation with Lactobacillus acidophilus, Lactobacillus rhamnosus, and Pediococcus acidilactici. After fermentation, the total sugar and protein content in the PFGF significantly decreased, while the lactic acid level and antioxidant activity of the PFGF increased. Afterward, we investigated the alleviating effect of PFGF on alcoholic liver injury in alcohol-fed mice. The results showed that the PFGF intervention reduced the necrosis of the liver cells, attenuated the inflammation of the liver and intestines, restored the liver function, increased the antioxidant factors of the liver, and maintained the cecum tissue barrier. Additionally, the results of the 16S rRNA sequencing analysis indicated that the PFGF intervention increased the relative abundance of beneficial bacteria, such as Lactobacillus, Ruminococcaceae, Parabacteroids, Parasutterella, and Alistipes, to attenuate intestinal inflammation. These results demonstrate that PFGF can potentially alleviate alcoholic liver damage by restoring the intestinal barrier and regulating the intestinal microflora.