University Strasbourg, INSERM U1109, MN3T (The Microenvironmental Niche in Tumorigenesis and Targeted Therapy), 3 avenue Molière, Strasbourg, Hautepierre, France; University Strasbourg, INSERM U1109, The Tumor Microenvironment Laboratory, Hôpital Civil, Institut d'Hématologie et d'Immunologie, Fédération de Médecine Translationnelle de Strasbourg (FMTS), 1 Place de l'Hôpital, 67091 Strasbourg, France.
University Basel, Tumor Matrix laboratory, Department of Biomedicine, Mattenstrasse 57, Basel, Switzerland.
Matrix Biol. 2022 Apr;108:20-38. doi: 10.1016/j.matbio.2022.02.007. Epub 2022 Feb 26.
The extracellular matrix molecule Tenascin-C (TNC) promotes cancer and chronic inflammation by multiple mechanisms. Recently, TNC was shown to promote an immune suppressive tumor microenvironment (TME) through binding soluble chemoattracting factors, thus retaining leukocytes in the stroma. TNC also binds to fibronectin (FN) and other molecules, raising the question of a potential common TNC binding mechanism. By sequence comparison of two TNC-interacting domains in FN, the fifth (FN5) and thirteenth (FN13) fibronectin type III domains we identified a MAtrix REgulating MOtif "MAREMO" or M-motif that is highly conserved amongst vertebrates. By sequence analysis, structural modeling and functional analysis we found also putative M-motifs in TNC itself. We showed by negative staining electron microscopic imaging that the M-motif in FN mediates interactions with FN as well as with TNC. We generated two M-motif mimetic peptides P5 and P13 resembling the M-motif in FN5 and FN13, respectively. By using structural information we modelled binding of these M-motif mimetics revealing a putative MAREMO binding site MBS in FN5 and TN3, respectively overlapping with the M-motif. We further demonstrated that the M-motif mimetic peptides blocked several functions of TNC, such as binding of TNC to FN, cell rounding on a mixed FN/TNC substratum, FN matrix expression and subsequent assembly, TNC-induced signaling and gene expression, TNC chemokine binding and dendritic cell retention, thus providing novel opportunities to inhibit TNC actions. Our results suggest that targeting the MAREMO/MBS interaction could be exploited for reducing inflammation and matrix functions in cancer and fibrosis.
细胞外基质分子 Tenascin-C（TNC）通过多种机制促进癌症和慢性炎症。最近，TNC 被证明通过结合可溶性趋化吸引因子来促进免疫抑制性肿瘤微环境（TME），从而将白细胞保留在基质中。TNC 还与纤维连接蛋白（FN）和其他分子结合，这引发了对潜在共同 TNC 结合机制的疑问。通过对 FN 中两个与 TNC 相互作用的结构域（第五个[FN5]和第十三个[FN13]纤维连接蛋白 III 结构域）的序列比较，我们鉴定出一个高度保守的基质调节基序“MAREMO”或 M 基序。通过序列分析、结构建模和功能分析，我们还在 TNC 本身中发现了潜在的 M 基序。我们通过负染色电子显微镜成像表明，FN 中的 M 基序介导与 FN 以及 TNC 的相互作用。我们生成了两个 M 基序模拟肽 P5 和 P13，分别类似于 FN5 和 FN13 中的 M 基序。我们利用结构信息对这些 M 基序模拟物进行了建模，揭示了 FN5 和 TN3 中分别存在的一个假定的 MAREMO 结合位点 MBS，该位点与 M 基序重叠。我们进一步证明，M 基序模拟肽阻断了 TNC 的几种功能，例如 TNC 与 FN 的结合、在混合 FN/TNC 基底上细胞的圆形化、FN 基质表达和随后的组装、TNC 诱导的信号转导和基因表达、TNC 趋化因子结合和树突状细胞保留，从而为抑制 TNC 作用提供了新的机会。我们的研究结果表明，靶向 MAREMO/MBS 相互作用可能被用于减少癌症和纤维化中的炎症和基质功能。
