Astrocytes in the spinal dorsal horn (SDH) exhibit diverse reactive phenotypes under neuropathic conditions, yet the mechanisms driving this diversity and its implications in chronic pain remain unclear. Here, we report that spared nerve injury (SNI) induces marked upregulation of both complement component 3 (C3⁺, A1-like) and S100 calcium-binding protein A10 (S100A10⁺, A2-like) astrocyte subpopulations in the SDH, with elevated microglial cytokines including interleukin-1α, tumor necrosis factor-α, and complement component 1q. Transcriptomic, immunohistochemical, and Western blot analyses reveal co-activation of multiple reactive astrocyte states over a unidirectional shift toward an A1-like phenotype. Fibroblast growth factor 8 (FGF8), a neuroprotective factor via FGFR3, mitigated microglia-induced C3⁺ astrocyte reactivity in vitro and suppressed spinal C3 expression and mechanical allodynia following intrathecal administration in SNI mice. These findings reveal a microglia-astrocyte signaling axis that promotes A1 reactivity and position FGF8 as a promising therapeutic candidate for neuropathic pain by modulating astrocyte heterogeneity.
Animals ; Astrocytes/drug effects* ; Neuralgia/pathology* ; Receptor, Fibroblast Growth Factor, Type 3/metabolism* ; Signal Transduction/physiology* ; Male ; Mice ; Microglia/drug effects* ; Fibroblast Growth Factor 8/pharmacology* ; Mice, Inbred C57BL ; Hyperalgesia/drug therapy* ; Spinal Cord/drug effects* ; Complement C3/metabolism* ; Spinal Cord Dorsal Horn/metabolism*

The cochlear auditory epithelium contains two types of sound receptors, inner hair cells (IHCs) and outer hair cells (OHCs). Mouse models for labelling juvenile and adult IHCs or OHCs exist; however, labelling for embryonic and perinatal IHCs or OHCs are lacking. Here, we generated a new knock-in Fgf8^P2A-3×GFP/+ (Fgf8^GFP/+) strain, in which the expression of a series of three GFP fragments is controlled by endogenous Fgf8 cis-regulatory elements. After confirming that GFP expression accurately reflects the expression of Fgf8, we successfully obtained both embryonic and neonatal IHCs with high purity, highlighting the power of Fgf8^GFP/+. Furthermore, our fate-mapping analysis revealed, unexpectedly, that IHCs are also derived from inner ear progenitors expressing Insm1, which is currently regarded as an OHC marker. Thus, besides serving as a highly favorable tool for sorting early IHCs, Fgf8^GFP/+ will facilitate the isolation of pure early OHCs by excluding IHCs from the entire hair cell pool.
Animals ; Mice ; Hair Cells, Auditory, Inner ; Cochlea/metabolism* ; Hair Cells, Auditory, Outer/metabolism* ; Disease Models, Animal ; Fibroblast Growth Factor 8/metabolism*

OBJECTIVE: To explore the molecular mechanism of fibroblast growth factor 8b (FGF8b) in promoting epithelial-mesenchymal transition in prostate cancer DU145 cells. METHODS: Cells were selected in three groups as follows: a block control group (DU145 cells), a negative control group [DU145 cells transfected with empty plasmid (pcDNA3.1/DU145)], and an experimental group [DU145 cells transfected with FGF8b (FGF8b/DU145)]. The activity of extracellular regulated protein kinases1/2( ERK1/2) pathway was detected by western-blot in the three groups. The FGF8b-DU145 cells and DU145 cells were cultured with PD98059 (an ERK kinase inhibitor) to observe microscopically the morphology changes within the cells. The experimental samples were also divided into four groups: FGF8b/DU145 cells cultured with 2% FBS (Group A); FGF8b/DU145 cells cultured with 2% FBS+PD98059 (50 μmol/L) (Group B); DU145 cells cultured with 2% FBS (Group C); DU145 cells cultured with FBS+PD98059 (50 μmol/L) (Group D). The expression of epithelial- mesenchymal transition (EMT) markers (E-cadherin, vimentin) were detected by western-blot analysis and the cell's mobility were detected by the Transwell chamber. RESULTS: The activity of ERK1/2 in the experimental group was significantly higher than that in the other two control groups; when ERK kinase inhibitor PD98059 was added to FGF8b/ DU145 cells, the expression of epithelial marker E-cadherin protein was significantly increased in group B compared with that in the group A (P<0.05). The expression of mesenchymal marker vimentin protein was significantly reduced in group B compared with that in group A (P<0.05). The cell migration assay suggested that cell migration was markedly decreased in group B (P<0.05) compared with that in group A. CONCLUSION EMT in prostate cancer induced by FGF8b can be mediated by ERK kinase pathway, in which mitogen-activated/extraceluer signal regulated kinase 1 (MEK1) may be a key factor. MEK1 could be an effective target in regulating the invasion and migration of prostate cancer.
Epithelial-Mesenchymal Transition ; genetics ; Fibroblast Growth Factor 8 ; genetics ; metabolism ; Flavonoids ; pharmacology ; Humans ; MAP Kinase Kinase 1 ; metabolism ; MAP Kinase Signaling System ; physiology ; Male ; Neoplasm Invasiveness ; Neoplasm Metastasis ; Prostatic Neoplasms ; genetics ; metabolism ; pathology ; Transfection ; Tumor Cells, Cultured

OBJECTIVETo investigate the effects of chitosan on the biological activities of the fibroblasts derived from different tissues.

METHODSThe biological activities of the fibroblasts derived from different tissues were evaluated with a MTT method for fibroblast proliferation, photic and electronic microscope for morphologic and subcellular structure, 3H-proline uptake method for collagen secretion and ELISA box for the secretion of TGF-beta 1, FGF-AB, and IL-8.

RESULTSThis study showed that the chitosan inhabited the proliferation of the fibroblasts and the secretion of the TGF-beta 1, FGF-AB and collagen of the fibroblasts with a dose-depended manner in the normal skin, hypertrophic scar and keloid groups, but it stimulated the IL-8. However, there were no significant differences among the three groups (P > 0.05).

CONCLUSIONThe chitosan could inhibit the growth, proliferation, biosynthesis and secretion of the fibroblasts, and it may be used to treat different scars.

Adolescent ; Adult ; Cell Division ; drug effects ; Chitin ; analogs & derivatives ; pharmacology ; Chitosan ; Dose-Response Relationship, Drug ; Female ; Fibroblast Growth Factors ; secretion ; Fibroblasts ; drug effects ; metabolism ; ultrastructure ; Hemostatics ; pharmacology ; Humans ; Interleukin-8 ; secretion ; Male ; Microscopy, Electron ; Peptide Fragments ; secretion ; Transforming Growth Factor beta ; secretion