精原干细胞微环境研究进展

精原干细胞(spermatogonia stem cells,SSCs)是一类在睾丸中具有长期自我更新和分化潜能的生殖细胞(germ cells,GCs),即位于基底膜上的组织干细胞,其自我更新和分化受到周围微环境的调控。近年来对SSCs的研究取得了一系列重要进展,为临床治疗部分男性不育患者带来了曙光。其中,微环境对SSCs的调节功能的研究尤为重要,微环境负责整合不同类型的细胞成分、细胞外基质、细胞外调节分子及激素等对SSCs的作用,从而调节SSCs命运。关于SSCs微环境的研究已开始逐步成为干细胞研究的主要内容之一。本文主要对小鼠(Mus musculus)SSCs微环境的细胞组成、调控因子以及特点等研究现状进行了综述,为深入研究SSCs微环境的结构和功能提供背景资料,希望在未来能够通过多种研究模式复用,发现更为丰富的细胞表型和微环境因子。

Lrrc34 Is Highly Expressed in SSCs and Is Necessary for SSC Expansi on In Vitro

Objective To discover critical genes contributing to the sternness and maintenance of spermatogonial stem cells(SSCs)and provide new insights into the function of the leucine-rich repeat(LRR)family member Lrrc34(leudne-rich repeat-containing 34)in SSCs from mice.Methods Bioinformatic methods,including differentially expressed gene(DEG),gene ontology(GO)enrichment and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway analyses,were used to uncover latent pluripotency-related genes.Reverse transcription-polymerase chain reaction(RT-PCR)and immunofluorescence analyses were utilized to verify the mRNA and protein expression levels,respectively.RNA interference of Lrrc34 using siRNA was performed to detect its transient impact on SSCs.Results Eight DEGs between ID4-EGFP+(G)and ID4-EGFP+/TSPAN8Hig11(TH),eight DEGs between G and ID4-EGFP+/TSPAN8Uw(TL)and eleven DEGs between TH and TL were discovered,and eleven proteinprotein interaction(PPI)modules were found to be significant in the PPI network of DEGs.One of the DEGs,Lrrc34,was selected as a potential pluripotency?related gene due to its differential expression among ID4-EGFP+spermatogonia subsets and its interaction with fibroblast growth factor 2 in the fifth module.Immunofluorescence experiments exhibited specific expression of Lrrc34 in a subpopulation of undifferentiated spermatogonia marked by LIN28A,and RT-PCR experiments confirmed the high expression of Lrrc34 in SSCs from P7 and adult mice.The transient knockdown of Lrrc34 in SSCs resulted in reduced colony sizes and significant changes in the transcriptome and apoptotic pathways.Conclusion Lrrc34 is highly expressed in mouse SSCs and is required for SSC proliferation in vitro through effects on transcriptome and signaling transduction pathways.

RING finger 138 deregulation distorts NF-κB signaling and facilities colitis switch to aggressive malignancy

Prolonged activation of nuclear factor(NF)-кB signaling significantly contributes to the development of colorectal cancer(CRC).New therapeutic opportunities are emerging from targeting this distorted cell signaling transduction.Here,we discovered the critical role of RING finger 138(RNF138)in CRC tumorigenesis through regulating the NF-кB signaling,which is independent of its Ubiquitin-E3 ligase activity involved in DNA damage response.RNF138^(−/−) mice were hyper-susceptible to the switch from colitis to aggressive malignancy,which coincided with sustained aberrant NF-кB signaling in the colonic cells.Furthermore,RNF138 suppresses the activation of NF-кB signaling pathway through preventing the translocation of NIK and IKK-Beta Binding Protein(NIBP)to the cytoplasm,which requires the ubiquitin interaction motif(UIM)domain.More importantly,we uncovered a significant correlation between poor prognosis and the downregulation of RNF138 associated with reinforced NF-кB signaling in clinical settings,raising the possibility of RNF138 dysregulation as an indicator for the therapeutic intervention targeting NF-кB signaling.Using the xenograft models built upon either RNF138-dificient CRC cells or the cells derived from the RNF138-dysregulated CRC patients,we demonstrated that the inhibition of NF-кB signaling effectively hampered tumor growth.Overall,our work defined the pathogenic role of aberrant NF-кB signaling due to RNF138 downregulation in the cascade events from the colitis switch to colonic neoplastic transformation and progression,and also highlights the possibility of targeting the NF-кB signaling in treating specific subtypes of CRC indicated by RNF138-ablation.