Role of epithelial-to-mesenchymal transition in the pulmonary fi brosis induced by paraquat in rats

BACKGROUND:This study aims to explore the characteristics of the epithelial-to-mesenchymal transition(EMT)process and its underlying molecular mechanisms in the period of paraquat(PQ)-induced pulmonary fi brosis(PF).METHODS:Picrosirius red staining and collagen volume fraction were utilized to evaluate the pathological changes of PQ-induced PF in rats.Immunohistochemistry,Western blot,and real-time reverse transcriptase-polymerase chain reaction(RT-PCR)were used to measure the protein and gene expression of EMT markers,EMT-associated transcription factors,and regulators of EMT-related pathways,respectively.RESULTS:The collagen deposition in the alveolar septum and increased PF markers were characteristics of pathological changes in PQ-induced PF,reached a peak on day 14 after PQ poisoning,and then decreased on day 21.The protein and gene expression of the fibrosis marker,EMT markers,transcription factors,and regulators of EMT-related signaling pathways signifi cantly increased at diff erent time points after PQ poisoning compared with corresponding controls(P<0.05),and most of them reached a peak on day 14,followed by a decrease on day 21.The gene expression of EMT markers was significantly correlated with PF markers,transcription factors,and regulators of EMT-related signaling pathways(P<0.05).The mRNA expression of transcription factors was signifi cantly correlated with that of TGF-β1 and Smad2(P<0.05 or P<0.01),instead of Wnt2 andβ-catenin(P>0.05).CONCLUSIONS:EMT process plays a role in the PQ-induced PF,in which most PF and EMT markers have a peak phenomenon,and its underlying molecular mechanisms might be determined by further studies.

Activation of glutamatergic neurons in the somatosensory cortex promotes remyelination in ischemic vascular dementia

Chronic cerebral hypoperfusion can cause progressive demyelination as well as ischemic vascular dementia,however no effective treatments are available.Here,based on magnetic resonance imaging studies of patients with white matter damage,we found that this damage is associated with disorganized cortical structure.In a mouse model,optogenetic activation of glutamatergic neurons in the somatosensory cortex significantly promoted oligodendrocyte progenitor cell(OPC)proliferation,remyelination in the corpus callosum,and recovery of cognitive ability after cerebral hypoperfusion.The therapeutic effect of such stimulation was restricted to the upper layers of the cortex,but also spanned a wide time window after ischemia.Mechanistically,enhancement of glutamatergic neuron-OPC functional synaptic connections is required to achieve the protection effect of activating cortical glutamatergic neurons.Additionally,skin stroking,an easier method to translate into clinical practice,activated the somatosensory cortex,thereby promoting OPC proliferation,remyelination and cognitive recovery following cerebral hypoperfusion.In summary,we demonstrated that activating glutamatergic neurons in the somatosensory cortex promotes the proliferation of OPCs and remyelination to recover cognitive function after chronic cerebral hypoperfusion.It should be noted that this activation may provide new approaches for treating ischemic vascular dementia via the precise regulation of glutamatergic neuron-OPC circuits.