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bioRxiv2025

FGF8 promotes lipid droplet accumulation via the FGFR1/p-p38 axis in chondrocytes

Chondrocytes store lipids in the form of lipid droplets (LDs) and maintain cartilage lipid metabolic homeostasis by consuming or regenerating LDs. This modulation is largely mediated by a series of biochemical factors. Fibroblast growth factor 8 (FGF8) is one of the most important factors involved in the proliferation, differentiation, and migration of chondrocytes, and has attracted increasing attention in the physiology and pathology of cartilage. However, the effect of FGF8 on LD accumulation in chondrocytes remains unclear. This study aimed to elucidate the role of FGF8 in LDs and explore the underlying biomechanism involved. The results showed that FGF8 promoted LD accumulation in chondrocytes by upregulating perilipin1 (Plin1) expression. FGF8 activates the cytoplasmic p-p38 signaling pathway via fibroblast growth factor receptor 1 (FGFR1) to increase LD accumulation in chondrocytes. Subsequent experiments with siRNAs and specific inhibitors further confirmed the importance of the FGFR1/p38 axis for LD accumulation in chondrocytes exposed to FGF8. These results increase our understanding of the role of FGF8 in the lipid metabolic homeostasis of chondrocytes and provide insights into the physiology and pathology of cartilage.

cell biology↗

bioRxiv2024

Effects of arbuscular mycorrhizal fungi on nitrogen uptake in cotton (Gossypium hirsutum L.) under low-nitrogen conditions

SummaryO_LICotton is an important global cash crop whose yield and quality are highly influenced by soil nitrogen. Therefore, examining the interactions between roots and arbuscular mycorrhizal fungi (AMF) under reduced nitrogen conditions is of great significance. C_LIO_LIWe investigated the effects of nitrogen application (0, 250, and 375 kg{middle dot} hm-2) on the AMF infection rate of cotton, the nitrogen content of each organ, root morphological characteristics and biomass, soil extracellular enzyme activity, and soil carbon and nitrogen content using a compartmentalized culture system. C_LIO_LIThe contribution of AMF to plant nitrogen was 10.40, 22.72, and 16.67% under high, low, and no nitrogen treatments, respectively. Under low-nitrogen conditions, the symbiosis between AMF and roots increased root surface area, tip number, branch number, mean diameter, and biomass; and increased soil extracellular enzyme activity (protease, NAG, PER, and PPO), the microbial biomass carbon-to-nitrogen ratio, active carbon content, and the soil nitrogen mineralization rate. Soil NO3--N, NH4+-N, and organic nitrogen content decreased, whereas the absorption of NO3--N by AMF hyphae was higher than that of NH4+-N. C_LIO_LIUnder low-nitrogen conditions, AMF promoted the decomposition of soil organic matter and the transformation of soil nitrogen through the action of hyphal microorganisms. C_LI

plant biology↗