Cells

Proteoglycans are macromolecules consisting of a core protein and one or more glycosaminoglycan side chains. Proteoglycans synthesized by vascular endothelial cells modulate various functions such as anticoagulant activity and vascular permeability. We previously reported that some heavy metals interfere with proteoglycan expression, and that organic–inorganic hybrid molecules, such as metal complexes and organometallic compounds, serve as useful tools to analyze proteoglycan synthesis mechanisms. However, the effects of metal compounds lacking electrophilicity on proteoglycan synthesis remain unclear. Au₂₅(SG)₁₈, a nanoscale gold cluster consisting of a metal core protected by gold–glutathione complexes, exhibits extremely low intramolecular polarity. In this study, we investigated the effect of Au₂₅(SG)₁₈ on proteoglycan synthesis in vascular endothelial cells. Au₂₅(SG)₁₈ accumulated significantly in vascular endothelial cells at low cell density and suppressed the expression of perlecan, a major heparan sulfate proteoglycan in cells, by inactivating ADP-ribosylation factor 6 (Arf6). Additionally, Au₂₅(SG)₁₈ reduced the expression of biglycan, a small dermatan sulfate proteoglycan, in vascular endothelial cells at low cell density; however, the underlying mechanisms remain unclear. Overall, our findings suggest that organic–inorganic hybrid molecules regulate the activity of Arf6-mediated protein transport to the extracellular space and that perlecan is regulated through this mechanism, highlighting the importance of Arf6-mediated extracellular transport for maintaining vascular homeostasis.

Porcine epidemic diarrhea virus (PEDV) has emerged as a major pathogen responsible for porcine diarrheal diseases, causing outbreaks of severe diarrhea and high mortality in neonatal piglets, thereby inflicting severe economic losses on the global swine industry. Current commercial PED vaccines, comprising conventional inactivated and live attenuated formulations, have exhibited progressively diminished efficacy in the face of emerging PEDV variants. The development of high-efficiency vaccine platforms is therefore critical for PED control. This study engineered a cellular membrane nanovesicle (CMN)-based vaccine, which differs from existing inactivated or subunit vaccines by presenting the PEDV spike (S) protein on the cell membranes to mimic the bilayer phospholipid structure of the viral envelope. The full-length S protein (FS, aa 19-1309) or a truncated S protein fragment (TS, aa 19-726) was expressed in Expi293F cells, followed by extraction of cell membranes to assemble antigen-displaying CMN vaccines. Compared with commercial live attenuated vaccine, administration of the CMN vaccine elicited high-titer neutralizing antibodies and elevated IFN-γ-producing CD8⁺ T cells in murine studies. Safety assessments revealed no adverse effects on body weight, hepatic/renal function indices, or histopathological parameters in vaccinated mice. Furthermore, immunization of piglets elicited notable humoral and CD8⁺ T cell immune responses. Collectively, the strategy of CMN-based vaccine described herein delivers a potential PEDV vaccine platform, thereby offering a novel avenue for next-generation veterinary vaccine development.

Taurine metabolism is emerging as an important player in cancer progression, yet its precise roles remain incompletely understood. Our study revealed that elevated serum Taurine levels and concomitant upregulation of its transporter, Slc6a6, are associated with enhanced tumor growth. Functionally, Slc6a6 overexpression drives tumor progression in vivo and accelerates cancer cell proliferation in vitro. Mechanistically, we identified a dual pro-oncogenic function for Slc6a6. First, Slc6a6 possesses intrinsic antioxidant regulatory capacity and further enhances cellular redox homeostasis by mediating the uptake of the antioxidant molecule Taurine. Second, beyond its metabolic role, Slc6a6 directly interacts with the cell cycle regulator Rprd1b to promote the G1/S phase transition, leading to uncontrolled proliferation. Clinically, bioinformatics analyses correlate high SLC6A6 expression with poor prognosis in breast cancer patients, underscoring its potential as a therapeutic target.