Vorinostat ameliorates IL-1α-induced reduction of type II collagen by inhibiting the expression of ELF3 in chondrocytes

Revisiting the role and mechanism of ELF3 in circadian clock modulation

The gene encoding EARLY FLOWERING3 (ELF3) is necessary for photoperiodic flowering and the normal regulation of circadian rhythms. It provides important information at the cellular level to uncover the biological mechanisms that improve plant growth and development. ELF3 interactions with transcription factors such as BROTHER OF LUX ARRHYTHMO (BOA), LIGHT-REGULATED WD1 (LWD1), PHYTOCHROME-INTERACTING FACTOR 4 (PIF4), PHYTOCHROME-INTERACTING FACTOR 7 (PIF7), and LUX ARRHYTHMO (LUX) suggest a role in evening complex (EC) independent pathways, demanding further investigation to elucidate the EC-dependent versus EC-independent mechanisms. The ELF3 regulation of flowering time about photoperiod and temperature variations can also optimize crop cultivation across diverse latitudes. In this review paper, we summarize how ELF3's role in the circadian clock and light-responsive flowering control in crops offers substantial potential for scientific advancement and practical applications in biotechnology and agriculture. Despite its essential role in crop adaptation, very little is known in many important crops. Consequently, comprehensive and targeted research is essential for extrapolating ELF3-related insights from Arabidopsis to other crops, utilizing both computational and experimental methodologies. This research should prioritize investigations into ELF3's protein-protein interactions, post-translational modifications, and genomic targets to elucidate its contribution to accurate circadian clock regulation.

Single-cell RNA sequence presents atlas analysis for chondrocytes in the talus and reveals the potential mechanism in coping with mechanical stress

Chondrocytes are indispensable for the function of cartilage because they provide the extracellular matrix. Therefore, gaining insight into the chondrocytes may be helpful in understanding cartilage function and pinpointing potential therapeutical targets for diseases. The talus is a part of the ankle joint, which serves as the major large joint that bears body weight. Compared with the distal tibial and fibula, the talus bears much more mechanical loading, which is a risk factor for osteoarthritis (OA). However, in most individuals, OA seems to be absent in the ankle, and the cartilage of the talus seems to function normally. This study applied single-cell RNA sequencing to demonstrate atlas for chondrocyte subsets in healthy talus cartilage obtained from five volunteers, and chondrocyte subsets were annotated. Gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses for each cell type, cell-cell interactions, and single-cell regulatory network inference and clustering for each cell type were conducted, and hub genes for each cell type were identified. Immunohistochemical staining was used to confirm the presence and distribution of each cell type. Two new chondrocyte subsets were annotated as MirCs and SpCs. The identified and speculated novel microenvironment may pose different directions in chondrocyte composition, development, and metabolism in the talus.

Physalin A Inhibits MAPK and NF-κB Signal Transduction Through Integrin αVβ3 and Exerts Chondroprotective Effect

Osteoarthritis (OA) is a common articular ailment presented with cartilage loss and destruction that is common observed in the elderly population. Physalin A (PA), a natural bioactive withanolide, exerts anti-inflammatory residences in more than a few diseases; however, little is known about its efficacy for OA treatment. Here, we explored the therapeutic effects and potential mechanism of PA in mouse OA. After the in vitro administration of PA, the expression of inflammation indicators including inducible nitric oxide synthase and cyclooxygenase-2 was low, indicating that PA could alleviate the IL-1β-induced chondrocyte inflammation response. Moreover, PA reduced IL-1β-induced destruction of the extracellular matrix by upregulating the gene expression of anabolism factors, including collagen II, aggrecan, and sry-box transcription factor 9, and downregulating the gene expression of catabolic factors, including thrombospondin motif 5 and matrix metalloproteinases. In addition, the chondroprotective effect of PA was credited to the inhibition of mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) signaling pathways. Furthermore, in vivo experiments showed that intra-articular injection of PA could alleviate cartilage destruction in a mouse OA model. However, the anti-inflammatory, anabolism enhancing, catabolism inhibiting, and MAPK and NF-κB signaling pathway inhibiting properties of PA on IL-1β-induced chondrocytes could be reversed when integrin αVβ3 is knocked down by siRNA. In conclusion, our work demonstrates that PA exhibits a chondroprotective effect that may be mediated by integrin αVβ3. Thus, PA or integrin αVβ3 might be a promising agent or molecular target for the treatment of OA.