Project description:Alzheimer's disease (AD) is one of the most common neurodegenerative diseases. So far, there is no effective treatment for this condition. Tetramethylpyrazine (TMP) is an alkaloid extracted from traditional Chinese medicine chuanxiong, which is mainly used in the treatment of ischemic stroke some related diseases. In this study, we studied the potential effects of TMP on AD progression by using two AD mouse models. 8-month-old 3xTg-AD mice received TMP treatment (10mg/kg/d) for 1 month, and 4-month-old APP/PS1-AD mice received TMP treatment (10mg/kg/d) for 2 months. The behavioral tests by step-down passive avoidance test (SDA), new object recognition (NOR) and Morris water maze (MWM) showed that TMP significantly improved the learning and memory impairment of two AD transgenic mice. In addition, TMP reduced Aß levels and tau phosphorylation. Venny analysis showed that 116 differentially expressed proteins were commonly changed in 3xTg mice vs WT mice and TMP treated mice vs untreated mice. The same, 130 differentially expressed proteins were commonly changed in APP/PS1 mice vs WT mice and TMP treated mice vs untreated mice. The functions of the common proteins modified by TMP in the two models were mainly related to mitochondrial function, synaptic function, cytoskeleton, GTP binding, ATP binding. Mitochondrial omics analysis revealed 21 and 20 differentially expressed mitochondrial proteins modified by TMP in 3xTg-AD mice and APP/PS1 mice, respectively. These differential proteins were located in mitochondrial inner membrane, mitochondrial outer membrane, mitochondrial gap and mitochondrial matrix, and the function of some proteins is closely related to oxidative phosphorylation of (OXPHOS). Western-blot further validated that TMP changed the expression of OXPHOS complex proteins (sdhb, ndufa10, uqcrfs1, cox5b, atp5a) in the hippocampus of the two AD mice. Taken together, our study demonstrated that TMP improved the cognitive impairment and AD-like pathology, and modified hippocampal proteome in the two AD mice models. The improvement of the behavioral and pathology might be associated with modification of mitochondrial protein profile by TMP. Our study suggested that TMP had the potential for the treatment of AD.

Project description:Sepsis is a severe and dysregulated inflammatory disease that often precedes the development of acute kidney injury (AKI) with consequent worsening outcome. The main characteristics of sepsis-induced AKI include endothelial cell (EC) dysfunction, infiltration of inflammatory cells, glomerular thrombosis, and renal tubular epithelial cells (RTEC) injury. Numerous studies have demonstrated that mammalian target of rapamycin (mTOR) activation has been implicated in the initiation and progression of renal injury in course of sepsis. However, little is known, about the molecular basis of mTOR role in EC and RTEC dysfunction. Here, we evaluate whether mTOR inhibition by Rapamycin (Rp) as potential strategy to ameliorate renal function and dissected the molecular mechanisms involved. In a mouse model of lipopolysaccharide (LPS)-induced AKI , LPS injection led to a time-dependent increase of serum creatinine and significant morphological changes in renal parenchyma associated with increased collagen deposits and endothelial dysfunction. Interestingly, Rp treatment significantly decreased creatine levels and preserved renal parenchyma, counteracting Endothelial-to mesenchymal transition (EndMT) process and early fibrosis through the inhibition of ERK pathway. Next, we examined the effects of LPS-TLR4 interaction in RTECs. Through a whole-genome DNA methylation analysis in cultured RTEC, we found that LPS induced aberrant methylation, particularly in regions involved in premature aging. The most represented genes were CD39 and WFS1. LPS stimulation of RTEC led to up-regulation of SA-β Gal and cell cycle arrest markers such as p21. In accordance, in endotoxemic mice, we found a decreased expression of CD39 concurrent with Klotho down-regulation. Administration of Rp exerted anti-aging effects in endotoxemic mice, preserving CD39 and Klotho expression. In conclusion, we demonstrated that mTOR inhibition could offer novel strategies to protect endothelial and tubular compartment from accelerated aging and fibrosis thus counteracting the progression to chronic kidney disease.

Project description:Staphylococcus aureus thymidine-dependent small-colony variants (TD-SCVs) are frequently isolated from patients with chronic S. aureus infections after long-term treatment with trimethoprim-sulfamethoxazole (TMP-SMX). In TD-SCVs, mutations of thymidylate synthase (thyA, TS), essential for DNA synthesis, occur. However, it has never been shown, that TMP-SMX is responsible for the induction and selection of TD-SCVs. Short-term exposure of TMP-SMX induced the TD-SCV phenotype morphologically as shown in transmission electron-microscopy and on the transcriptional level by qRT-PCR in wild-type S. aureus, while selection of TD-SCVs with thyA mutations occurred only rarely after long-term exposure. In reversion experiments with clinical TD-SCVs, all revertants revealed compensating mutations at the initially identified mutation site. Whole DNA microarray analysis of a thyA deletion mutant (∆thyA), which exhibited the typical TD-SCV phenotype, identified tremendous alterations compared to the wild-type. Important virulence regulators such as agr, arlRS, sarA and major virulence determinants including hla, hlb, sspA, sspB and geh were down-regulated, while genes associated with the colonization capacity like fnbA, fnbB, spa, clfB, sdrC and sdrD were up-regulated. The expression of genes involved in pyrimidine and purine metabolism as well as in nucleotide interconversion changed significantly. The ∆thyA-mutant was attenuated in virulence in both, a Caenorhabditis elegans killing model and an acute murine pneumonia model. Furthermore, competition experiments in vitro and in vivo (using a chronic pneumonia mouse model) revealed a survival and growth advantage of the ∆thyA-mutant under low thymidine conditions and TMP-SMX exposure. In conclusion, our results clearly show for the first time that TMP-SMX induces the TD-SCV phenotype after short-term exposure in S. aureus and that long-term exposure selects thyA mutations providing an advantage for TD-SCVs under specified conditions. Thus, our results help to understand the dynamic processes of induction and selection of S. aureus TD-SCVs during TMP-SMX exposure.

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Single-cell transcriptome analysis revealed cellular reprogramming following Tetramethylpyrazine treatment in LPS-induced acute lung injury

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