Ogbu Chinemerem P, de Las Alas Mason, Mandriota Alexandria M, Liu Xiangdong, Kapoor Srajan, Choudhury Jagrity, Ruma Yasmeen N, Goodman Michael C, Sanders Charles R, Gonen Tamir, Kossiakoff Anthony A, Duffey Michael E, Vecchio Alex J
Department of Structural Biology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY 14203, USA.
Department of Physiology and Biophysics, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY 14203, USA.
PNAS Nexus. 2025 Jun 6;4(6):pgaf189. doi: 10.1093/pnasnexus/pgaf189. eCollection 2025 Jun.
Claudins are a 27-member family of membrane proteins that form and fortify specialized cell contacts in endothelium and epithelium called tight junctions. Tight junctions restrict paracellular transport through tissues by forming molecular barriers between cells. Claudin-binding molecules thus hold promise for modulating tight junction permeability to deliver drugs or as therapeutics to treat tight junction-linked disease. The development of claudin-binding molecules, however, is hindered by their physicochemical intractability and small targetable surfaces. Here, we determine that a synthetic antibody fragment (sFab) that we developed binds with nanomolar affinity directly to 10 claudin subtypes and other distantly related claudin family members but not to other tight junction-localized membrane proteins. It does so by targeting the extracellular surfaces of claudins, which we verify by applying this sFab to a model intestinal epithelium and observe that it opens paracellular barriers comparable to a known, but application limited, tight junction modulating protein. This pan-claudin-binding molecule holds potential for both basic and translational applications as it is a probe of claudin and tight junction structure in vitro and in vivo and a tool to modulate the permeability of tight junctions broadly across tissue barriers.
闭合蛋白是一个由27种成员组成的膜蛋白家族，在内皮细胞和上皮细胞中形成并强化称为紧密连接的特殊细胞连接。紧密连接通过在细胞间形成分子屏障来限制跨细胞旁运输。因此，闭合蛋白结合分子有望调节紧密连接的通透性，以递送药物或作为治疗紧密连接相关疾病的疗法。然而，闭合蛋白结合分子的开发受到其物理化学难处理性和可靶向小表面的阻碍。在这里，我们确定我们开发的一种合成抗体片段（sFab）以纳摩尔亲和力直接结合10种闭合蛋白亚型和其他远亲的闭合蛋白家族成员，但不结合其他紧密连接定位的膜蛋白。它通过靶向闭合蛋白的细胞外表面来实现这一点，我们将这种sFab应用于模型肠上皮细胞进行验证，并观察到它打开的细胞旁屏障与一种已知但应用有限的紧密连接调节蛋白相当。这种泛闭合蛋白结合分子在基础和转化应用方面都具有潜力，因为它是体外和体内闭合蛋白及紧密连接结构的探针，也是一种广泛调节跨组织屏障紧密连接通透性的工具。
