Role of Swiprosin-1/EFHD2 as a biomarker in the development of chronic diseases

EFHD2 suppresses intestinal inflammation by blocking intestinal epithelial cell TNFR1 internalization and cell death

TNF acts as one pathogenic driver for inducing intestinal epithelial cell (IEC) death and substantial intestinal inflammation. How the IEC death is regulated to physiologically prevent intestinal inflammation needs further investigation. Here, we report that EF-hand domain-containing protein D2 (EFHD2), highly expressed in normal intestine tissues but decreased in intestinal biopsy samples of ulcerative colitis patients, protects intestinal epithelium from TNF-induced IEC apoptosis. EFHD2 inhibits TNF-induced apoptosis in primary IECs and intestinal organoids (enteroids). Mice deficient of Efhd2 in IECs exhibit excessive IEC death and exacerbated experimental colitis. Mechanistically, EFHD2 interacts with Cofilin and suppresses Cofilin phosphorylation, thus blocking TNF receptor I (TNFR1) internalization to inhibit IEC apoptosis and consequently protecting intestine from inflammation. Our findings deepen the understanding of EFHD2 as the key regulator of membrane receptor trafficking, providing insight into death receptor signals and autoinflammatory diseases.

Modulation of biomolecular phase behavior by metal ions

Liquid-liquid phase separation (LLPS) appears to be a newly appreciated aspect of the cellular organization of biomolecules that leads to the formation of membraneless organelles (MLOs). MLOs generate distinct microenvironments where particular biomolecules are highly concentrated compared to those in the surrounding environment. Their thermodynamically driven formation is reversible, and their liquid nature allows them to fuse with each other. Dysfunctional biomolecular condensation is associated with human diseases. Pathological states of MLOs may originate from the mutation of proteins or may be induced by other factors. In most aberrant MLOs, transient interactions are replaced by stronger and more rigid interactions, preventing their dissolution, and causing their uncontrolled growth and dysfunction. For these reasons, there is great interest in identifying factors that modulate LLPS. In this review, we discuss an enigmatic and mostly unexplored aspect of this process, namely, the regulatory effects of metal ions on the phase behavior of biomolecules.