Recently, diffusion models have emerged as a promising paradigm for molecular design and optimization. However, most diffusion-based molecular generative models focus on modeling 2D graphs or 3D geometries, with limited research on molecular sequence diffusion models. The International Union of Pure and Applied Chemistry (IUPAC) names are more akin to chemical natural language than the Simplified Molecular Input Line Entry System (SMILES) for organic compounds. In this work, we apply an IUPAC-guided conditional diffusion model to facilitate molecular editing from chemical natural language to chemical language (SMILES) and explore whether the pre-trained generative performance of diffusion models can be transferred to chemical natural language. We propose DiffIUPAC, a controllable molecular editing diffusion model that converts IUPAC names to SMILES strings. Evaluation results demonstrate that our model outperforms existing methods and successfully captures the semantic rules of both chemical languages. Chemical space and scaffold analysis show that the model can generate similar compounds with diverse scaffolds within the specified constraints. Additionally, to illustrate the model's applicability in drug design, we conducted case studies in functional group editing, analogue design and linker design.

Objective:To investigate the effect of plasma-derived exosomes on the function of human venous endothelial cells in normal and rheumatoid arthritis patients.Methods:The plasma of healthy controls and rheumatoid arthritis patients was collected, and the surface protein markers were identified by transmission electron microscopy (TEM) and NTA. The effects of exosomes on endothelial cell proliferation and migration and invasion were detected by CCK8, cell scratch, Transwell chamber experiments; real time polymerase chain reaction (RT-PCR). The changes of cell secretion hypoxia inducible factor 1α (HIF-1α), vascular endothelial growth factor (VEGF) content were detected. The comparison between the two groups was performed by t test. Results:The double concave disc-like cystic vesicles were observed by transmission electron microscopy, nanoparticle tracking analysis (NTA) showed that the diameter was about 50-150 nm. Western blotting showed that the relative molecular weights of flotillin1 and CD81, on the surface of plasma exosomes were 47 000 and 26 000, respectively. Endothelial cell activity decreased with the increase of exosomes concentration, but the difference between the two groups was not significant( t=1.86, P>0.05). Compared with normal human con-exo, ra-exo significantly inhibited endothelial cell migration [(2.24±0.23) vs (1.46±0.13), t=6.60, P<0.05], reduced invasive capacity [(0.673±0.030) vs (0.827±0.030), t=8.11, P<0.05] in patients with rheumatoid arthritis. In addition, the ability to secrete HIF-1a, VEGF cytokines was decreased significantly, the difference was statistically significant [(0.706±0.020) vs (0.908±0.040), t=10.10, P<0.05; (0.692±0.010) vs (0.841±0.020), t=14.90, P<0.05]. Conclusion:The exosomes from plasma may play an important role in RA and vascular injury.

Objective To study the molecular mechanism of activator protein (AP)-1 and macrophage inflammatory protein (MIP)-1? in adjuvant arthritis and the effects of sodium arsenite (SA) on AP-1 and MIP-1. Methods Forty Wistar female rats were randomly divided into 4 groups: normal control (NC), model (M), low concentration sodium arsenite (SA1) and high concentration sodium arsenite group (SA2). The SA1 group and the SA2 group were treated with sodium arsenite (0.5 mg?kg-1?d-1 and 1.0 mg?kg-1?d-1) through abdominal cavity injection for 20 days, the normal control group and the model group were treated with saline (0.2 ml/d). The levels of C reactive protein (CRP) in every group were determined by biochemistry, the C-fos and MIP-1? expression of synovium in 4 groups were determined by immunohistochemistry. Results The levels of CRP in the M group were increased more than NC group (P