RESUMO
Neuroinflammation has been gaining attention as one of the potential causes of neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis in recent years. The suppression of excessive proinflammatory responses is expected to be a target for the treatment and prevention of neurodegenerative diseases. Collapsin response mediator protein 4 (CRMP4) is involved in cytoskeleton-associated axonal guidance in the developing brain. Recently, the involvement of CRMP4 in several pathological conditions, including inflammation induced by lipopolysaccharide (LPS), a widely used inflammatory molecule, has been reported. However, the role of CRMP4 in LPS-induced inflammation in vivo remains largely unknown. In this study, we generated microglia-specific CRMP4 knockout mice for the first time and examined the role of CRMP4 in an LPS-induced brain inflammation model. We found that microglia after LPS injection in substantia nigra was significantly reduced in Crmp4-/- mice compared to Crmp4+/+mice. The increased expression of IL-10 in striatum samples was downregulated in Crmp4-/- mice. A significant reduction in Iba1 expression was also observed in microglia-specific Crmp4 knockout mice compared with that in control mice. In contrast, the expression of IL-10 did not change in these mice, whereas arginase 1 (Arg1) expression was significantly suppressed. These results demonstrate the involvement of CRMP4 in LPS-induced inflammation in vivo, that CRMP4 suppresses microglial proliferation in a cell-autonomous manner.
Assuntos
Lipopolissacarídeos , Camundongos Knockout , Microglia , Proteínas do Tecido Nervoso , Doenças Neuroinflamatórias , Animais , Lipopolissacarídeos/farmacologia , Microglia/metabolismo , Microglia/efeitos dos fármacos , Proteínas do Tecido Nervoso/metabolismo , Proteínas do Tecido Nervoso/genética , Camundongos , Doenças Neuroinflamatórias/metabolismo , Doenças Neuroinflamatórias/induzido quimicamente , Inflamação/metabolismo , Inflamação/induzido quimicamente , Interleucina-10/metabolismo , Substância Negra/metabolismo , Substância Negra/efeitos dos fármacos , Camundongos Endogâmicos C57BL , Corpo Estriado/metabolismo , Corpo Estriado/efeitos dos fármacos , Masculino , Proteínas dos Microfilamentos/metabolismo , Arginase/metabolismoRESUMO
The transcription factor SRY-related HMG box 9 (Sox9) is essential for chondrogenesis. Mutations in and around SOX9 cause campomelic dysplasia (CD) characterized by skeletal malformations. Although the function of Sox9 in this context is well studied, the mechanisms that regulate Sox9 expression in chondrocytes remain to be elucidated. Here, we have used genome-wide profiling to identify 2 Sox9 enhancers located in a proximal breakpoint cluster responsible for CD. Enhancer activity of E308 (located 308 kb 5' upstream) and E160 (located 160 kb 5' upstream) correlated with Sox9 expression levels, and both enhancers showed a synergistic effect in vitro. While single deletions in mice had no apparent effect, simultaneous deletion of both E308 and E160 caused a dwarf phenotype, concomitant with a reduction of Sox9 expression in chondrocytes. Moreover, bone morphogenetic protein 2-dependent chondrocyte differentiation of limb bud mesenchymal cells was severely attenuated in E308/E160 deletion mice. Finally, we found that an open chromatin region upstream of the Sox9 gene was reorganized in the E308/E160 deletion mice to partially compensate for the loss of E308 and E160. In conclusion, our findings reveal a mechanism of Sox9 gene regulation in chondrocytes that might aid in our understanding of the pathophysiology of skeletal disorders.
Assuntos
Displasia Campomélica , Diferenciação Celular , Condrócitos , Condrogênese , Fatores de Transcrição SOX9 , Fatores de Transcrição SOX9/metabolismo , Fatores de Transcrição SOX9/genética , Animais , Condrócitos/metabolismo , Camundongos , Displasia Campomélica/genética , Displasia Campomélica/patologia , Displasia Campomélica/metabolismo , Condrogênese/genética , Diferenciação Celular/genética , Elementos Facilitadores Genéticos/genética , Cromatina/metabolismo , Cromatina/genética , Regulação da Expressão Gênica no Desenvolvimento , Camundongos Knockout , Proteína Morfogenética Óssea 2/metabolismo , Proteína Morfogenética Óssea 2/genética , Humanos , Desenvolvimento Ósseo/genéticaRESUMO
Tumor tissues consist of heterogeneous cells that originate from stem cells; however, their cell fate determination program remains incompletely understood. Using patient-derived organoids established from patients with advanced colorectal cancer (CRC), we evaluated the potential of olfactomedin 4 (OLFM4)+ stem cells to produce a bifurcated lineage of progenies with absorptive and secretory properties. In the early phases of organoid reconstruction, OLFM4+ cells preferentially gave rise to secretory cells. Additionally, we found that Paneth-like cells, which do not exist in the normal colon, were induced in response to Notch signaling inhibition. Video recordings of single OLFM4+ cells revealed that organoids containing Paneth-like cells were effectively propagated and that their selective ablation led to organoid collapse. In tumor tissues, Paneth-like cells were identified only in the region where tumor cells lost cell adhesion. These findings indicate that Paneth-like cells are directly produced by OLFM4+ stem cells and that their interaction contributes to tumor formation by providing niche factors. This study reveals the importance of the cell fate specification program for building a complete tumor cellular ecosystem, which might be targeted with novel therapeutics.