RESUMO
BACKGROUND: The hyperpolarization-activated cyclic nucleotide-gated cation channel (HCN1) is predominantly located in key regions associated with epilepsy, such as the neocortex and hippocampus. Under normal physiological conditions, HCN1 plays a crucial role in the excitatory and inhibitory regulation of neuronal networks. In temporal lobe epilepsy, the expression of HCN1 is decreased in the hippocampi of both animal models and patients. However, whether HCN1 expression changes during epileptogenesis preceding spontaneous seizures remains unclear. OBJECTIVE: The aim of this study was to determine whether the expression of HCN1 is altered during the epileptic prodromal phase, thereby providing evidence for its role in epileptogenesis. METHODS: We utilized a cobalt wire-induced rat epilepsy model to observe changes in HCN1 during epileptogenesis and epilepsy. Additionally, we also compared HCN1 alterations in epileptogenic tissues between cobalt wire- and pilocarpine-induced epilepsy rat models. Long-term video EEG recordings were used to confirm seizures development. Transcriptional changes, translation, and distribution of HCN1 were assessed using high-throughput transcriptome sequencing, total protein extraction, membrane and cytoplasmic protein fractionation, western blotting, immunohistochemistry, and immunofluorescence techniques. RESULTS: In the cobalt wire-induced rat epilepsy model during the epileptogenesis phase, total HCN1 mRNA and protein levels were downregulated. Specifically, the membrane expression of HCN1 was decreased, whereas cytoplasmic HCN1 expression showed no significant change. The distribution of HCN1 in the distal dendrites of neurons decreased. During the epilepsy period, similar HCN1 alterations were observed in the neocortex of rats with cobalt wire-induced epilepsy and hippocampus of rats with lithium pilocarpine-induced epilepsy, including downregulation of mRNA levels, decreased total protein expression, decreased membrane expression, and decreased distal dendrite expression. CONCLUSIONS: Alterations in HCN1 expression and distribution are involved in epileptogenesis beyond their association with seizure occurrence. Similarities in HCN1 alterations observed in epileptogenesis-related tissues from different models suggest a shared pathophysiological pathway in epileptogenesis involving HCN1 dysregulation. Therefore, the upregulation of HCN1 expression in neurons, maintenance of the HCN1 membrane, and distal dendrite distribution in neurons may represent promising disease-modifying strategies in epilepsy.
RESUMO
Mesenchymal stem cells (MSCs) are associated with pulmonary protection and longevity. We separated chicken bone marrow-derived mesenchymal stem cells (BM-MSCs); investigated whether BM-MSCs can improve lipopolysaccharide (LPS)-induced lung and distal organ injury; and explored the underlying mechanisms. Ninety-six male ICR (6 weeks old) mice were randomly divided into three groups: Sham, LPS, and LPS + MSC groups. The mice were intratracheally injected with 5 mg/kg LPS to induce acute lung injury (ALI). The histopathological severity of injury to the lung, liver, kidney, heart, and aortic tissues was detected. Wet/dry ratio, protein concentrations in bronchoalveolar lavage fluid (BALF), BALF cell counts, inflammatory cytokine levels in serum, inflammatory cytokine gene expression, and oxidative stress-related indicators were detected. In addition, a survival analysis was performed in sixty male ICR mice (6 weeks old, 18-20 g). This study used chicken BM-MSCs, which are easier to obtain and more convenient than other animal or human MSCs, and have MSC-associated properties, such as a colony forming ability, multilineage differentiation potential, and certain phenotypes. BM-MSCs administration significantly improved the survival rate, systemic inflammation, and the histopathological severity of lung, liver, kidney, and aortic injury during ALI. BM-MSCs administration reduced the levels of inflammatory factors in BALF, the infiltration of neutrophils, and oxidative stress injury in lung tissue. In addition, BM-MSCs administration reduced TRL4 and Mdy88 mRNA expression during ALI. Chicken BM-MSCs serve as a potential alternative resource for stem cell therapy and exert a prominent effect on LPS-induced ALI and extrapulmonary injury, in part through TRL4/Mdy88 signaling and inhibition of neutrophil inflammation and oxidative stress injury.
