Background: Plasma metabolites are associated with cognitive and physical function in the elderly. Because cerebral small vessel disease (SVD) and neurodegeneration are common causes of cognitive and physical function decline, the primary objective of this study was to investigate the associations of six plasma metabolites (two plasma phosphatidylcholines [PCs]: PC aa C36:5 and PC aa 36:6 and four sphingomyelins [SMs]: SM C26:0, SM [OH] C22:1, SM [OH] C22:2, SM [OH] C24:1) with magnetic resonance imaging (MRI) features of cerebral SVD and neurodegeneration in older adults. Methods: This study included 238 older adults in the Atherosclerosis Risk in Communities study at the fifth exam. Multiple linear regression was used to assess the association of each metabolite (log-transformed) in separate models with MRI measures except lacunar infarcts, for which binary logistic regression was used. Results: Higher concentrations of plasma PC aa C36:5 had adverse associations with MRI features of cerebral SVD (odds ratio of 1.69 [95% confidence interval: 1.01, 2.83] with lacunar infarct, and beta of 0.16 log [cm³] [0.02, 0.30] with log [White Matter Hyperintensities (WMH) volume]) while higher concentrations of 3 plasma SM (OH)s were associated with higher total brain volume (beta of 12.0 cm³ [5.5, 18.6], 11.8 cm³ [5.0, 18.6], and 7.3 cm³ [1.2, 13.5] for SM [OH] C22:1, SM [OH] C22:2, and SM [OH] C24:1, respectively). Conclusions: This study identified associations between certain plasma metabolites and brain MRI measures of SVD and neurodegeneration in older adults, particularly higher SM (OH) concentrations with higher total brain volume.

The WRKY gene family in plants regulates the plant's response to drought through regulatory networks and hormone signaling. AfWRKY20 (MT859405) was cloned from A. fruticosa (Amorpha fruticosa,A. fruticosa) seedlings using RT-PCR. The binding properties of the AfWRKY20 protein and the W-box (a DNA cis-acting element) were verified both in vivo and in vitro using EMSA and Dual-Luciferase activity assays. RT-qPCR detected that the total expression level of AfWRKY20 in leaves and roots was 22 times higher in the 30% PEG6000 simulated drought treatment compared to the untreated group. Under the simulated drought stress treatments of sorbitol and ABA (abscisic acid,ABA), the transgenic tobacco with the AfWRKY20 gene showed enhanced drought resistance at the germination stage, with significantly increased germination rate, green leaf rate, fresh weight, and root length compared to the WT (wild type,WT) tobacco. In addition, the SOD (superoxide dismutase,SOD)activity, chlorophyll content, and Fv/Fm ratio of AfWRKY20 transgenic tobacco were significantly higher than those of the WT tobacco under natural drought stress, while the MDA (malondialdehyde,MDA) content and DAB (3,3'-diaminobenzidine,DAB) and NBT (nitroblue tetrazolium,NBT) staining levels were lower. The expression levels of oxidation kinase genes (NbSOD, NbPOD, and NbCAT) in transgenic tobacco under drought stress were significantly higher than those in WT tobacco. This enhancement in gene expression improved the ability of transgenic tobacco to detoxify ROS (reactive oxygen species,ROS). The survival rate of transgenic tobacco after natural drought rehydration was four times higher than that of WT tobacco. In summary, this study revealed the regulatory mechanism of AfWRKY20 in response to drought stress-induced ABA signaling, particularly in relation to the ROS. This finding provides a theoretical basis for understanding the pathways of WRKY20 involved in drought stress, and offers genetic resources for molecular plant breeding aimed at enhancing drought resistance.