meng, j. | bioRxiv Science

bioRxiv2025

Identification of pyroptosis-related diagnostic model relate to immune infiltration in osteoarthritis

BackgroundOsteoarthritis (OA) is a common chronic diseases which were associated with aging and progressive joint dysfunction. Pyroptosis, a novel mode of cell death. The effect of pyroptosis on osteoarthritis (OA) progression is still in the exploratory stage, and the specific mechanism is unclear. MethodsOA data sets were obtained from the GEO databases website. Bioinformatics analysis was conducted to identify pyroptosis-related genes (PRGs), construct a pyroptosis-related diagnostic model, and identify subtypes. We established the random forest (RF) model as well as a nomogram of differentially expressed PRGs. The association between immunity and pyroptosis was comprehensively explored. Finally, the expression levels of 3 OA characteristic genes were verified by qRT-PCR and immunohistochemistry. ResultsSeven differentially expressed PRGs (CASP3, GPX4, NOD1, TIRAP, SCAF11, CASP4, and CASP9) were obtained by differential analysis to establish RF models, and three important OA genes (CASP9, TIRAP, and SCAF11) were obtained. ROC curve proved that the established model had high diagnostic accuracy. Based on the above three important PRGs, a high-precision nomogram model is constructed. Two PRG models are determined by consensus clustering method. The enrichment degree of immune cells in cluster A was higher than that in cluster B, suggesting that cluster A might be related to the occurrence and development of OA. GPX4 was found to be positively correlated with higher immune infiltration. Finally, the expression levels of 3 OA characteristic genes were verified by qRT-PCR and immunohistochemistry. ConclusionWe constructed an effective prognostic model according to PRGs in OA and integrated explored the association between pyroptosis and immunity-related elements. This article provides a strong point for investigating directed immunotherapy methods with novelty for OA.

immunology↗

bioRxiv2023

Boosting Ascomycin Production through n-Butanol Addition in the Fermentation Process of Streptomyces hygroscopicus var. ascomyceticus ATCC 14891

Ascomycin (FK520) is a macrolide antibiotic known for its immunosuppressive activities. In this study, we screened several short-chain alcohols to enhance titer of FK520 in Streptomyces hygroscopicus var. ascomyceticus ATCC 14891, with a particular focus on n-butanol addition. After optimizing the n-butanol addition process, we achieved a FK520 yield of 569.37 mg/L with 0.8% n-butanol addition at 27 h, representing a 1.72-fold increase compared with the control group. We subsequently found that ROS levels of n-butanol addition group reached 1.49x105 RFU/g biomass at 29 h, which was 3.02 times higher than the control group. The 0.8% n-butanol addition also promote the accumulation of biosynthesis precursors for FK520 production. The highest ethylmalonyl-CoA content surged to 93.1 nmol/g DCW at 48 h, marking a 5.3-fold increase. Likewise, the highest methylmalonyl-CoA and malonyl-CoA levels increased remarkable 4.33-fold and 3.33-fold compared with the control group at 72 h and at 120 h, respectively. Then, we explored the effects of oxygen supply on FK520 production with n-butanol addition, and improving oxygen supply caused a significant increase of FK520 in shake flask fermentation. Our research has revealed that addition of short-chain alcohols can regulate carbon flux toward FK520 biosynthesis by supplementing various CoA-esters, including ethylmalonyl-CoA, methylmalonyl-CoA, and malonyl-CoA.

microbiology↗