State Key Laboratory of Bioreactor Engineering, Biomedical Nanotechnology Center, Shanghai Collaborative Innovation Center for Biomanufacturing Technology, School of Biotechnology, East China University of Science and Technology, Shanghai 200237, China.
Department of Obstetrics and Gynecology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China.
Biomacromolecules. 2022 Aug 8;23(8):3318-3328. doi: 10.1021/acs.biomac.2c00431. Epub 2022 Jul 20.
Phenol-soluble modulin α3 (PSMα3) can self-assemble into fibrous assemblies with a unique "cross-α" sheet structure, which serves as a key virulence factor in the infection of . However, the structure-cytotoxicity relationships of PSMα3 still remain elusive. Herein, we utilized the strategy of salt-inducing assembly polymorphism to controllably prepare three PSMα3 assemblies with morphological and structural distinctions, including amorphous aggregates (AAs), rigid fibrils (RFs), and oligomers/curvilinear fibrils (OCFs), which provided a convincing method to facilitate the structure-cytotoxicity investigation of PSMα3 assemblies. Our results affirmed that amyloid fibrillation was essential for the enhancement of PSMα3 cytotoxicity, which was proved based on the evidence that RFs and OCFs both triggered more obvious cytotoxicity than AAs. Furthermore, our study also demonstrated that the cytotoxicity was severely dependent on the size and structure of PSMα3 fibrils. In detail, smaller OCFs rich in α-helices exhibited stronger virulence than RFs with larger sizes and low α-helical contents. The cytotoxicity caused by such fibrils was achieved via a membrane-disrupting mechanism, in which RFs and OCFs might be prone to membrane thinning and perforation, respectively. This strategy of salt-inducing PSMα3 assembly polymorphism facilitated the comprehension of the relationship between the characteristics of PSMα3 assemblies and their cytotoxicity and was also helpful to understanding the intrinsic assembly mechanism of the PSMα3.
酚可溶性调制素 α3（PSMα3）可以自组装成具有独特“交叉-α”片层结构的纤维组装体，作为感染中的关键毒力因子。然而，PSMα3 的结构-细胞毒性关系仍然难以捉摸。本文利用盐诱导组装多态性的策略，可控地制备了三种具有形态和结构差异的 PSMα3 组装体，包括无定形聚集体（AAs）、刚性纤维（RFs）和低聚物/曲线纤维（OCFs），为研究 PSMα3 组装体的结构-细胞毒性提供了一种有说服力的方法。结果证实淀粉样纤维形成对于增强 PSMα3 的细胞毒性至关重要，这一证据基于 RFs 和 OCFs 都比 AAs 引发更明显的细胞毒性的事实。此外，我们的研究还表明，细胞毒性严重依赖于 PSMα3 纤维的大小和结构。具体而言，富含α-螺旋的较小 OCFs 比具有较大尺寸和低α-螺旋含量的 RFs 具有更强的毒性。这种纤维引起的细胞毒性是通过破坏膜的机制实现的，其中 RFs 和 OCFs 可能分别容易导致膜变薄和穿孔。这种盐诱导 PSMα3 组装多态性的策略有助于理解 PSMα3 组装体的特征与其细胞毒性之间的关系，也有助于理解 PSMα3 的内在组装机制。
