Multi-networks connectivity at baseline predicts the clinical efficacy of left angular gyrus-navigated rTMS in the spectrum of Alzheimer's disease: A sham-controlled study.

INTRODUCTION: Neuro-navigated repetitive transcranial magnetic stimulation (rTMS) is effective in alleviating cognitive deficits in Alzheimer's disease (AD). However, the strategy for target determination and the mechanisms for cognitive improvement remain unclear. METHODS: One hundred and thirteen elderly subjects were recruited in this study, including both cross-sectional (n = 79) and longitudinal experiments (the rTMS group: n = 24; the sham group: n = 10). The cross-sectional experiment explored the precise intervention target based on the cortical-hippocampal network. The longitudinal experiment investigated the clinical efficacy of neuro-navigated rTMS treatment over a four-week period and explored its underlying neural mechanism using seed-based and network-based analysis. Finally, we applied connectome-based predictive modeling to predict the rTMS response using these functional features at baseline. RESULTS: RTMS at a targeted site of the left angular gyrus (MNI: -45, -67, 38) significantly induced cognitive improvement in memory and language function (p < 0.001). The improved cognition correlated with the default mode network (DMN) subsystems. Furthermore, the connectivity patterns of DMN subsystems (r = 0.52, p = 0.01) or large-scale networks (r = 0.85, p = 0.001) at baseline significantly predicted the Δ language cognition after the rTMS treatment. The connectivity patterns of DMN subsystems (r = 0.47, p = 0.019) or large-scale networks (r = 0.80, p = 0.001) at baseline could predict the Δ memory cognition after the rTMS treatment. CONCLUSION: These findings suggest that neuro-navigated rTMS targeting the left angular gyrus could improve cognitive function in AD patients. Importantly, dynamic regulation of the intra- and inter-DMN at baseline may represent a potential predictor for favorable rTMS treatment response in patients with cognitive impairment.

Proteome changes associated with dormancy release of Dongxiang wild rice seeds.

Seed dormancy provides optimum timing for seed germination and subsequent seedling growth, but the mechanism of seed dormancy is still poorly understood. Here, we used Dongxiang wild rice (DXWR) seeds to investigate the dormancy behavior and the differentially changed proteome in embryo and endosperm during dormancy release. DXWR seed dormancy was caused by interaction of embryo and its surrounding structure, and was an intermediate physiological dormancy. During seed dormancy release, a total of 109 and 97 protein spots showed significant change in abundance and were successfully identified in embryo and endosperm, respectively. As a result of dormancy release, the abundance of nine proteins involved in storage protein, cell defense and rescue and energy changed in the same way in both embryo and endosperm, while 67 and 49 protein spots changed differentially in embryo and endosperm, respectively. Dormancy release of DXWR seeds was closely associated with degradation of storage proteins in both embryo and endosperm. At the same time, the abundance of proteins involved in metabolism, glycolysis and TCA cycle, cell growth and division, protein synthesis and destination and signal transduction increased in embryos while staying constant or decreasing in endosperms.

Proteomic Analysis Reveals Different Involvement of Embryo and Endosperm Proteins during Aging of Yliangyou 2 Hybrid Rice Seeds.

Seed aging is a process that results in a delayed germination, a decreased germination percentage, and finally a total loss of seed viability. However, the mechanism of seed aging is poorly understood. In the present study, Yliangyou 2 hybrid rice (Oryza sativa L.) seeds were artificially aged at 100% relative humidity and 40°C, and the effect of artificial aging on germination, germination time course and the change in protein profiles of embryo and endosperm was studied to understand the molecular mechanism behind seed aging. With an increasing duration of artificial aging, the germination percentage and germination rate of hybrid rice seeds decreased. By comparing the protein profiles from the seeds aged for 0, 10 and 25 days, a total of 91 and 100 protein spots were found to show a significant change of more than 2-fold (P < 0.05) in abundance, and 71 and 79 protein spots were identified, in embryos and endosperms, respectively. The great majority of these proteins increased in abundance in embryos (95%) and decreased in abundance in endosperms (99%). In embryos, most of the identified proteins were associated with energy (30%), with cell defense and rescue (28%), and with storage protein (18%). In endosperms, most of the identified proteins were involved in metabolism (37%), in energy (27%), and in protein synthesis and destination (11%). The most marked change was the increased abundance of many glycolytic enzymes together with the two fermentation enzymes pyruvate decarboxylase and alcohol dehydrogenase in the embryos during aging. We hypothesize that the decreased viability of hybrid rice seeds during artificial aging is caused by the development of hypoxic conditions in the embryos followed by ethanol accumulation.

Proteomics analysis reveals distinct involvement of embryo and endosperm proteins during seed germination in dormant and non-dormant rice seeds.

Seed germination is a complex trait which is influenced by many genetic, endogenous and environmental factors, but the key event(s) associated with seed germination are still poorly understood. In present study, the non-dormant cultivated rice Yannong S and the dormant Dongxiang wild rice seeds were used as experimental materials, we comparatively investigated the water uptake, germination time course, and the differential proteome of the effect of embryo and endosperm on germination of these two types of seeds. A total of 231 and 180 protein spots in embryo and endosperm, respectively, showed a significant change in abundance during germination. We observed that the important proteins associated with seed germination included those involved in metabolism, energy production, protein synthesis and destination, storage protein, cell growth and division, signal transduction, cell defense and rescue. The contribution of embryo and endosperm to seed germination is different. In embryo, the proteins involved in amino acid activation, sucrose cleavage, glycolysis, fermentation and protein synthesis increased; in endosperm, the proteins involved in sucrose cleavage and glycolysis decreased, and those with ATP and CoQ synthesis and proteolysis increased. Our results provide some new knowledge to understand further the mechanism of seed germination.

Identification of embryo proteins associated with seed germination and seedling establishment in germinating rice seeds.

Seed germination is a critical phase in the plant life cycle, but the mechanism of seed germination is still poorly understood. In the present study, rice (Oryza sativa L. cv. Peiai 64S) seeds were sampled individually when they reached different germination stages, quiescent, germinated sensu stricto, germinated completely and seedling, and were used to study the changes in the embryo proteome. A total of 88 protein spots showed a significant change in abundance during germination in water, and the results showed an activation of metabolic processes. Cell division, cell wall synthesis, and secondary metabolism were activated at late seed germination and during preparation for subsequent seedling establishment. Cycloheximide (CHX) at 70µM inhibited seedling establishment without an apparent negative effect on seed germination, while CHX at 500µM completely blocked seed germination. We used this observation to identify the potentially important proteins involved in seed germination (coleoptile protrusion) and seedling establishment (coleoptile and radicle protrusion). Twenty-six protein spots, mainly associated with sugar/polysaccharide metabolism and energy production, showed a significant difference in abundance during seed germination. Forty-nine protein spots, mainly involved in cell wall biosynthesis, proteolysis as well as cell defense and rescue, were required for seedling establishment. The results help improve our understanding of the key events (proteins) involved in germination and seedling development.

A proteomic analysis of rice seed germination as affected by high temperature and ABA treatment.

Seed germination is a critical phase in the plant life cycle, but the specific events associated with seed germination are still not fully understood. In this study, we used two-dimensional gel electrophoresis followed by mass spectrometry to investigate the changes in the proteome during imbibition of Oryza sativa seeds at optimal temperature with or without abscisic acid (ABA) and high temperature (germination thermoinhibition) to further identify and quantify key proteins required for seed germination. A total of 121 protein spots showed a significant change in abundance (1.5-fold increase/decrease) during germination under all conditions. Among these proteins, we found seven proteins specifically associated with seed germination including glycosyl hydrolases family 38 protein, granule-bound starch synthase 1, Os03g0842900 (putative steroleosin-B), N-carbamoylputrescine amidase, spermidine synthase 1, tubulin α-1 chain and glutelin type-A; and a total of 20 imbibition response proteins involved in energy metabolism, cell growth, cell defense and storage proteins. High temperature inhibited seed germination by decreasing the abundance of proteins involved in methionine metabolism, amino acid biosynthesis, energy metabolism, reserve degradation, protein folding and stress responses. ABA treatment inhibited germination and decreased the abundance of proteins associated with methionine metabolism, energy production and cell division. Our results show that changes in many biological processes including energy metabolism, protein synthesis and cell defense and rescue occurred as a result of all treatments, while enzymes involved in methionine metabolism and weakening of cell wall specifically accumulated when the seeds germinated at the optimal temperature.