Osteoarthritis (OA) is a prevalent joint disorder marked primarily by the progressive breakdown of articular cartilage. Pyroptosis, an inflammatory programmed cell death mechanism, exacerbates OA progression. Ginsenoside Rh2 (Rh2), a bioactive compound derived from traditional Chinese medicine, has shown potential therapeutic effects in OA. However, its underlying molecular mechanisms in OA treatment remain to be fully elucidated. To investigate the therapeutic potential of Rh2, an in vitro OA model was generated via LPS treatment of human chondrocytes (C-28/I2). The anti-inflammatory and anti-pyroptotic properties of Rh2 were subsequently assessed by quantifying the levels of key inflammatory cytokines using ELISA, immunofluorescence assessment of extracellular matrix components, Western blot analysis of pyroptosis-related proteins, and LDH release assays. The interaction between Rh2 and platelet-activating factor receptor (PAFR) was verified using molecular docking and cellular thermal shift assay (CETSA). Finally, functional validation of Rh2's target specificity was achieved through transfection of PAFR overexpression or knockdown plasmids into chondrocytes. In the chondrocyte OA model, Rh2 treatment significantly suppressed PAFR expression and inhibited the NF-κB signaling pathway, resulting in the significant downregulation of key pyroptosis-related proteins, including NLRP3, cleaved Caspase-1, and GSDMD-N, as well as a decrease in the secretion of pro-inflammatory cytokines IL-1β and IL-18. These effects collectively attenuated chondrocyte pyroptosis and protected cartilage cells. Conversely, PAFR overexpression completely abolished the protective effects of Rh2, demonstrating the critical role of PAFR in mediating Rh2's therapeutic actions. Using a human chondrocyte cell line (C-28/I2) and focusing on PAFR as the target gene, our findings demonstrate that Rh2 alleviates chondrocyte pyroptosis in vitro by specifically targeting PAFR to suppress NF-κB signaling. These results provide a mechanistic basis for further investigation of Rh2 in more complex OA models. The PAFR/NF-κB axis represents a candidate pathway for cartilage protection.

Acidic soils (pH < 5.5) contain elevated levels of phytotoxic aluminum (Al3+) and iron (Fe2+/Fe3+); however, the mechanisms underlying plant adaptation to their coexistence remain poorly understood. Commelina communis, an invasive weed prevalent on acid soils of tea gardens, was exposed to Al (50 and 100 µM) and Fe (100 µM), individually and in combination (pH 4.0), for four weeks. Plant biomass remained unaffected under single or combined stress, accompanied by reciprocal reductions in foliar metal concentrations. However, chlorosis, reduced photosynthetic pigments, and altered photochemical parameters indicated exacerbated chloroplast damage under combined Al and Fe toxicity. Conversely, phenolic and anthocyanin contents in leaves and oxalate in roots peaked under dual stress, coinciding with significantly reduced stress markers. Histochemical analysis revealed that Al3+ and Fe2+ mutually inhibited binding to root tips, reducing membrane injury under co-treatment. Fourier-transform infrared (FTIR) spectroscopy of root tissues showed substantial decreases in cell wall-associated pectin and hemicellulose under Al stress, excess Fe and co-exposure, potentially limiting Al3+ and Fe2+/Fe3+ binding and mitigating rhizotoxic effects. Al treatment alone suppressed malate and citrate exudation, whereas Fe toxicity increased their release. In contrast, oxalate and phenolics exudation were enhanced by Al and Fe, with maximum excretion under combined exposure. These findings reveal two interaction patterns: additive toxicity affecting chloroplast function, and synergistic enhancement of internal and rhizosphere-based detoxification. Taken together, these findings explain the robust spread of C. communis in acid soils, provide a framework for future research on metal co-tolerance, and may inform acid soil management strategies and the development of stress-resilient cultivars.

Viruses transmitted by the obligate biotrophic parasite Polymyxa graminis cause substantial losses in agriculture worldwide. A better knowledge of the infection process may lead to the identification of novel strategies for virus control. The coat protein readthrough (CP-RT) protein or its homologs, present in all P. graminis-transmitted viruses, are transmission factors of the viruses. To better characterize CP-RT function, we modified an infectious Japanese soil-borne wheat mosaic virus (JSBWMV) cDNA clone to express fluorescent protein-tagged CP-RT and analyzed the protein during infection in the model host plant Nicotiana benthamiana. We found that JSBWMV CP-RT localized to and self-interacted at the endoplasmic reticulum (ER) network and in small cortical particles during infection. The particles moved along the ER network and associated with sub-ER sites, most likely ER import sites, as indicated by co-localization with Sar1-GTP:GFP and AtSYP72:GFP. Particles were still present after reabsorption of the Golgi into the ER network after Brefeldin A treatment, thus they were not an intrinsic part of the Golgi-ER compartment. In natural CP-RT deletion mutants, the localization to the ER network was lost, while localization to the particles was maintained. Consistent with earlier data our findings from transmission experiments in hydroponic barley culture indicate that an intact JSBWMV CP-RT may be important for virus transmission by the vector, as more wild type CP-RT forms compared to mutant CP-RT forms accumulated in newly infected plants. ER-association of CP-RT may thus be important for virus transmission and early infection processes.

Humic acid (HA) is a redox-active organic compound that can regulate cell metabolism to produce antioxidant metabolites against oxidative stress. Haematococcus lacustrisis a green microalga and is found to be a rich source of astaxanthin. In this research, the impact of HA was studied on the growth mechanisms and production of antioxidant metabolites through dynamic responses of pigments, proteins, carbohydrates, secondary messengers of H2O2 and Ca2+, gamma-aminobutyric acid (GABA), and enzyme activities in H. lacustris. Results revealed that HA at 80µM concentration is a suitable treatment to induce astaxanthin production and cell growth. Cell numbers increased significantly under HA80, and the trend was to enter the red aplanosporephase at the stationary growth phase. High HA concentration (120µM) increased astaxanthin content but considerably reduced cell number and size. HA80 enhanced astaxanthin (5.39mg L-1), flavonoid (15.64mgg-1 DW), and phenolic (55.64mgg-1 DW) contents after 9days of induction time, which was accompanied by a significant reduction in the chlorophyll pigments, proteins, and carbohydrate contents. The increase in total phenolic content was associated with enhanced phenylalanineammonia-lyase activity. H2O2 accumulation decreased by HA80 at the late stationary growth phase. Putrescine and spermidine contents were promoted under HA80, while gamma-aminobutyric acid (GABA) and Ca2+ contents were reduced from the logarithmic phase to the early stationary growth phase. Succinate dehydrogenase (SDH) activity was promoted in the TCA cycle, and the GABA shunt was activated to regulate the ROS level. Findings indicate that the impact of HA on cell growth and astaxanthin production is associated with HA concentration and cell growth phase. HA can regulate ROS levels at the stationary growth phase by inducing polyamine metabolism and an antioxidant defense system.

Large interstitial telomeric regions are considered remnants and markers of chromosomal rearrangements or a result of several suggested molecular mechanisms of telomere repeats accumulation. More rare are cases when large interstitial repeats are found not close to, but at a distance from the centromere. However, synapsis, recombination, and effects on chromatin near these regions during meiotic prophase I have not been sufficiently studied. Using the model of three snake species of the genus Vipera: V. berus, V. nikolskii, V. renardi, we studied interstitial telomere sites (ITSs) in the pachytene nuclei of primary spermatocytes. We discovered an unusual composite chromosome in the species under study with two ITSs located far from the centromere. In V. berus, two very large adjacent ITS blocks were found on bivalent 5. In the other two species, V. nikolskii and V. renardi, two ITSs are also present on bivalent 5, but they are significantly smaller and barely distinguishable by FISH on pachytene bivalents. The possibility of forming crossing-over sites is shown between the two ITSs. Apparently, the three studied viper species received this complex structure of chromosome 5 from their common ancestor. However, the transformation of these telomeric repeat regions during evolution in the species under study occurred differently. Possible mechanisms of modifications of the telomeric regions are discussed.

Physcomitrium patens (formerly Physcomitrella patens), a model moss species, has emerged as an invaluable system for studying autophagy in plants. This review highlights the unique advantages of P. patens for autophagy research, including its efficient homologous recombination in mitotic cells, simple body plan, haploid-presiding life cycle, and accessibility to microscopic observation. I discuss recent advances in understanding autophagy mechanisms in P. patens, particularly focusing on the role of core autophagy-related (ATG) genes in growth, development, stress responses, and cell death. The characterization of autophagy-deficient mutants revealed unexpected roles of autophagy in promoting cell death under oxidative stress and desiccation, in contrast with classical survival functions. I also examine the conservation and divergence of the autophagy machinery between mosses and vascular plants, emphasizing how P. patens bridges evolutionary gaps in our understanding of plant autophagy. Finally, I outline future perspectives on the use of this model system to address fundamental questions about selective autophagy, autophagosome dynamics, and the integration of autophagy with developmental programs.