Inhibition of progesterone receptor membrane component-1 exacerbates neonatal hypoxic-ischemic cerebral damage in male mice

Progesterone Receptor Membrane Component 1 Regulates Cellular Stress Responses and Inflammatory Pathways in Chronic Neuroinflammatory Conditions

Alzheimer's disease (AD) is the leading cause of dementia and is one of the neurodegenerative diseases that are caused by neuronal death due to various triggers. Neuroinflammation plays a critical role in the development of AD. The neuroinflammatory response is manifested by pro-inflammatory cytokines, such as interleukin (IL)-1β, IL-6, and tumor necrosis factor-α; various chemokines; nitrous oxide; and reactive oxygen species. In this study, we evaluated the relevance of progesterone receptor membrane component 1 (PGRMC1), which is expressed in the brain cells during the induction of neuroinflammation. A lipopolysaccharide (LPS)-induced chronic neuroinflammation model and Pgrmc1 knockdown cells were used to assess the inflammatory cytokine levels, AD-related factors, inflammation-related signaling, and cell death. Pgrmc1 knockout (KO) mice had higher IL-1β levels after treatment with LPS compared with those of wild-type (WT) mice. Furthermore, Pgrmc1 KO mice had higher levels of inflammatory factors, endoplasmic reticulum stress indicators, and AD-associated markers compared with those of WT mice who underwent LPS treatment or not. Finally, these indicators were observed in vitro using U373-MG astrocytes. In conclusion, the loss of PGRMC1 may promote neuroinflammation and lead to AD.

Gain-of-function of progesterone receptor membrane component 2 ameliorates ischemic brain injury

OBJECTIVE

Progesterone receptor membrane component 2 (PGRMC2) belongs to the membrane-associated progesterone receptor family, which regulates multiple pathophysiological processes. However, the role of PGRMC2 in ischemic stroke remains unexplored. The present study sought to determine the regulatory role of PGRMC2 in ischemic stroke.

METHODS

Male C57BL/6J mice were subjected to middle cerebral artery occlusion (MCAO). The protein expression level and localization of PGRMC2 were examined by western blotting and immunofluorescence staining. The gain-of-function ligand of PGRMC2 (CPAG-1, 45 mg/kg) was intraperitoneally injected into sham/MCAO mice, and brain infarction, blood-brain barrier (BBB) leakage, and sensorimotor functions were evaluated by magnetic resonance imaging, brain water content, Evans blue extravasation, immunofluorescence staining, and neurobehavioral tests. The astrocyte and microglial activation, neuronal functions, and gene expression profiles were revealed by RNA sequencing, qPCR, western blotting, and immunofluorescence staining after surgery and CPAG-1 treatment.

RESULTS

Progesterone receptor membrane component 2 was elevated in different brain cells after ischemic stroke. Intraperitoneal delivery of CPAG-1 reduced infarct size, brain edema, BBB leakage, astrocyte and microglial activation, and neuronal death, and improved sensorimotor deficits after ischemic stroke.

CONCLUSION

CPAG-1 acts as a novel neuroprotective compound that could reduce neuropathologic damage and improve functional recovery after ischemic stroke.

Avermectin induces carp neurotoxicity by mediating blood-brain barrier dysfunction, oxidative stress, inflammation, and apoptosis through PI3K/Akt and NF-κB pathways

Avermectin, a "low toxicity insecticide", has been widely used in recent years, but its non-target toxicity, especially to aquatic organisms, has been neglected. In this study, we evaluated the neurotoxic effects of avermectin on carp by establishing a 96 h avermectin acute toxicity test, and its possible mechanism was discussed. The 96 h LC₅₀ of avermectin in carp was found to be 24.04 μg/L. Therefore, 3.005 μg/L and 12.02 μg/L were used as the low-dose and high-dose groups, respectively, to investigate the neurotoxic effects of avermectin on carp. The results of high-performance liquid chromatography (HPLC) analysis showed that avermectin accumulated in the carp brain. Histopathological observation and immunohistochemical analysis (IHC) of TNF-α and Bax showed that avermectin exposure led to inflammatory cell infiltration and neuronal necrosis. The mRNA levels of tight junction genes and the IHC results of ZO-1 and Occludin showed that the structure of the blood-brain barrier (BBB) was destroyed. Biochemical analysis showed that avermectin induced the accumulation of MDA in the brain and decreased the activity of antioxidant enzymes CAT and SOD, leading to oxidative stress. In addition, avermectin induces brain inflammation by activating NF-κB pathway and releasing inflammatory factors IL-1β, IL-6, TNF-α and iNOS. TEM and TUNEL assays showed that exposure to avermectin induced apoptosis in brain. what is more, the expression of apoptosis-related genes and proteins suggested that avermectin-induced apoptosis may be associated with inhibition of the PI3K/Akt signaling pathway. This study also showed that avermectin-induced NF-κB signaling activation was partially dependent on its upstream PI3K/Akt signaling pathway. Therefore, this study concludes that avermectin can induce neurotoxicity in carp by disrupting the blood-brain barrier structure and generating oxidative stress, inflammation, and apoptosis and that NF-κB and PI3K/Akt signaling pathways are involved in this process.