Treatment with oxoglaucine can enhance host resistance to Candida albicans infection of mice with adjuvant arthritis

Potent Zinc(II)-Based Immunogenic Cell Death Inducer Triggered by ROS-Mediated ERS and Mitochondrial Ca2+ Overload

Zn1 and Zn2 are Zn-based complexes that activate the immunogenic cell death (ICD) effect by Ca2+-mediated endoplasmic reticulum stress (ERS) and mitochondrial dysfunction. Compared with Zn1, Zn2 effectively caused reactive oxidative species (ROS) overproduction in the early phase, leading to ERS response. Severe ERS caused the release of Ca2+ from ER to cytoplasm and further to mitochondria. Excessive Ca2+ in mitochondria triggered mitochondrial dysfunction. The damage-associated molecular patterns (DAMPs) of CRT, HMGB1, and ATP occurred in T-24 cells exposed to Zn1 and Zn2. The vaccination assay demonstrated that Zn1 and Zn2 efficiently suppressed the growth of distant tumors. The elevated CD8+ cytotoxic T cells and decreased Foxp3+ cells in vaccinated mice supported our conclusion. Moreover, Zn1 and Zn2 improved the survival rate of mice compared with oxaliplatin. Collectively, our findings provided a new design strategy for a zinc-based ICD inducer via ROS-induced ERS and mitochondrial Ca2+ overload.

Oxoglaucine mediates Ca2+ influx and activates autophagy to alleviate osteoarthritis through the TRPV5/calmodulin/CAMK-II pathway

BACKGROUND AND PURPOSE

Stimulation of calcium influx and suppression of autophagy play important roles in the pathogenesis of osteoarthritis (OA). In this study, we used a novel inhibitor of TRPV5 cation channels - oxoglaucine to attenuate progression of deterioration and pathological changes in OA patient-derived chondrocytes and OA animal model, by activating autophagy.

EXPERIMENTAL APPROACH

Inhibition by oxoglaucine of calcium influx was assessed in cells.. Analyses were also carried out to investigate the effect of oxoglaucine on OA by detection of anti-inflammatory response, TRPV5/CAMK-II/calmodulin pathway, autophagy, and cartilage protection both in vitro and in vivo. demonstrated by macroscopic evaluation and histological findings.

KEY RESULTS

Oxoglaucine suppressed expression of proinflammatory and apoptosis-related proteins, including TNF-α, IL-6, IL-1β, MMP-13, CASP-3, and BAX, and prevented matrix degradation in OA chondrocytes. It also successfully blocked Ca²⁺ influx, activating autophagy dose-dependently asshown by up-regulated expression of LC-3II/I, Beclin-1, ATG5, ATG7, higher autophagic influx and formation of autophagic vesicles. It also decreased expression of mRNA and protein of TRPV5, CAMK-II, and calmodulin. Conversely, 1,25-dihydroxyvitamin D3, anagonist of TRPV5 channels, reversed the oxoglaucine-induced calcium influx inhibition and autophagy activation, demonstrating the association of oxoglaucine with TRPV5. Further, oxoglaucine prevented the apoptosis and matrix degradation of articular cartilage in a rat model of OA.

CONCLUSION AND IMPLICATIONS

Oxoglaucine protects against cartilage damage by blocking the TRPV5/CAMK-II/calmodulin pathway to inhibit Ca²⁺ influx and activate autophagy. Our results indicate that oxoglaucine has the potential to become a candidate drug for treatment of OA.

Phosphatidylinositol 4-kinase III beta is the target of oxoglaucine and pachypodol (Ro 09-0179) for their anti-poliovirus activities, and is located at upstream of the target step of brefeldin A

In recent years, phosphatidylinositol 4-kinase III beta (PI4KB) has emerged as a conserved target of anti-picornavirus compounds. In the present study, PI4KB was identified as the direct target of the plant-derived anti-picornavirus compounds, oxoglaucine and pachypodol (also known as Ro 09-0179). PI4KB was also identified as the target via which pachypodol interferes with brefeldin A (BFA)-induced Golgi disassembly in non-infected cells. Oxysterol-binding protein (OSBP) inhibitor also has interfering activity against BFA. It seems that this interference is not essential for the anti-poliovirus (PV) activities of BFA and PI4KB/OSBP inhibitors. BFA inhibited early to late phase PV replication (0 to 6 hr postinfection) as well as PI4KB inhibitor, but with some delay compared to guanidine hydrochloride treatment. In contrast with PI4KB/OSBP inhibitors, BFA inhibited viral nascent RNA synthesis, suggesting that BFA targets some step of viral RNA synthesis located downstream of the PI4KB/OSBP pathway in PV replication. Our results suggest that PI4KB is a major target of anti-picornavirus compounds identified in vitro for their anti-picornavirus activities and for some uncharacterized biological phenomena caused by these compounds, and that BFA and PI4KB/OSBP inhibitors synergistically repress PV replication by targeting distinct steps in viral RNA replication.