MiR-132-3p suppresses peritoneal fibrosis induced by peritoneal dialysis via targeting TGF-ß1/Smad2/3 signaling pathway.

BACKGROUND: Peritoneal fibrosis (PF) is the main complication of peritoneal dialysis (PD) and the most common cause of cessation from PD. There is still no effective therapeutic approach to reserve PF. We aimed to investigate the role of miR-132-3p and underlying potential mechanisms in PF. METHODS: A total of 18 Sprague-Dawley (SD) rats were divided randomly into three groups (n = 6): (i)Control group (ii)PF group (iii)PF+Losartan group; Rats in the PF group and PF+Losartan group received daily intraperitoneal injections of 3 mg/kg chlorhexidine for 14 days, and rats in the PF+Losartan group simultaneously received daily intraperitoneal injections of 2 mg/kg losartan for 14 days. The control group was injected with saline in the same volume. Met-5A cells were treated for 24h with TGF-ß1 dissolved in recombinant buffered saline at a concentration of 10 ng/ml, meanwhile, PBS solution as a negative control. The human peritoneal solution was collected for the detection of miR-132-3p. RESULTS: In vivo, SD rats were infused with chlorhexidine to establish PF model, and we found that miR-132-3p significantly decreased and the expressions of transforming growth factor-ß1 (TGF-ß1), and Smad2/3 were up-regulated in PF. In vitro, miR-132-3p mimics suppressed TGF-ß1/Smad2/3 activity, whereas miR-132-3p inhibition activated the pathway. In human peritoneal solution, we found that the expression of miR-132-3p decreased in a time-dependent model and its effect became more pronounced with longer PD duration. CONCLUSION: MiR-132-3p ameliorated PF by suppressing TGF-ß1/Smad2/3 activity, suggesting that miR-132-3p represented a potential therapeutic approach for PF.

Polysaccharides from Dendrobium officinale delay diabetic kidney disease interstitial fibrosis through LncRNA XIST/TGF-ß1.

PURPOSE: Renal interstitial fibrosis is a pathological manifestation of the progression of diabetic kidney disease (DKD). Dendrobium officinale polysaccharides (DOP), one of the major active components of Dendrobium officinale, have hypoglycemic and hypolipidemic effects and are used clinically to treat diabetes. However, the role of DOP in delaying DKD progression remains unclear. This study aimed to explore the potential mechanisms by which DOP delays DKD renal interstitial fibrosis. METHODS: Using db/db mice as a model of DKD, we administered DOP by gavage and observed its therapeutic effectiveness. Employing ASO technology, we knocked down lncRNA XIST expression in kidney tissues and detected the expression of lncRNA XIST, TGF-ß1, and renal interstitial fibrosis-related molecules. RESULTS: DOP was primarily composed of monosaccharides, with 91.57% glucose and 1.41% mannose, forming a spheroid-like structure. It has a high polydispersity index with an Mw/Mn of 6.146, and the polysaccharides are mainly connected by 4-Man(p) and 4-Glc(p) linkages. In the kidneys of db/db mice, lncRNA XIST and TGF-ß1 are highly expressed; however, their expression is significantly reduced after gastric infusion with DOP, and upon knockdown of lncRNA XIST, it might delay the progression of renal interstitial fibrosis in DKD. CONCLUSION: DOP may delay the progression of DKD renal interstitial fibrosis through the regulation of the LncRNA XIST/TGF-ß1 related fibrotic pathway. This provides a new perspective for clinical strategies to delay the progression of DKD renal interstitial fibrosis.

Genomic characterization of WRKY transcription factors related to secoiridoid biosynthesis in Gentiana macrophylla.

Gentiana macrophylla is one of Chinese herbal medicines in which 4 kinds of iridoids or secoiridoids, such as loganic acid, sweroside, swertiamarin, and gentiopicroside, are identified as the dominant medicinal secondary metabolites. WRKY, as a large family of transcription factors (TFs), plays an important role in the synthesis of secondary metabolites in plants. Therefore, WRKY genes involved in the biosynthesis of secoiridoids in G. macrophylla were systematically studied. First, a comprehensive genome-wide analysis was performed, and 42 GmWRKY genes were identified, which were unevenly distributed in 12 chromosomes. Accordingly, gene structure, collinearity, sequence alignment, phylogenetic, conserved motif and promoter analyses were performed, and the GmWRKY proteins were divided into three subfamilies based on phylogenetic and multiple sequence alignment analyses. Moreover, the enzyme-encoding genes of the secoiridoid biosynthesis pathway and their promoters were then analysed, and the contents of the four secoiridoids were determined in different tissues. Accordingly, correlation analysis was performed using Pearson's correlation coefficient to construct WRKY gene-enzyme-encoding genes and WRKY gene-metabolite networks. Meanwhile, G. macrophylla seedlings were treated with methyl jasmonate (MeJA) to detect the dynamic change trend of GmWRKYs, biosynthetic genes, and medicinal ingredient accumulation. Thus, a total of 12 GmWRKYs were identified to be involved in the biosynthesis of secoiridoids, of which 8 (GmWRKY1, 6, 12, 17, 33, 34, 38 and 39) were found to regulate the synthesis of gentiopicroside, and 4 (GmWRKY7, 14, 26 and 41) were found to regulate the synthesis of loganic acid. Taken together, this study systematically identified WRKY transcription factors related to the biosynthesis of secoiridoids in G. macrophylla, which could be used as a cue for further investigation of WRKY gene functions in secondary metabolite accumulation.

Quantitative MRI Analysis of Brachial Plexus and Limb-Girdle Muscles in Upper Extremity Onset Amyotrophic Lateral Sclerosis.

BACKGROUND: Recent evidence highlights the potential of axonal degeneration as a biomarker for amyotrophic lateral sclerosis (ALS) detection. However, the diagnostic potential of peripheral nerve axon changes in ALS remains unclear. PURPOSE: To evaluate the diagnostic performance of quantitative MRI of the brachial plexus and limb-girdle muscles (LGMs) in patients with upper extremity onset of ALS. STUDY TYPE: Retrospective. POPULATION: 47 patients with upper extremity onset of ALS and 20 healthy volunteers. FIELD STRENGTH/SEQUENCE: 3-T, three-dimensional sampling perfection with application-optimized contrasts using different flip angle evolutions with short-tau inversion recovery sequences, T2-weighted turbo spin-echo Dixon sequence. ASSESSMENT: The cross-sectional area (CSA) and nerve-muscle T2 signal intensity ratio (nT2) of the bilateral brachial plexus as well as the CSA and fat fraction (FF) of the bilateral LGMs were assessed by two radiologists. Disease severity and clinical stage of ALS patients were assessed by two neurologists. STATISTICAL TESTS: Student's t-test, Wilcoxon rank-sum test, binary logistic regression, interclass correlation coefficient, receiver operating characteristic analysis, and correlation analysis were performed for MRI quantitative metrics and clinical variables. Significance level: P < 0.05. RESULTS: In the affected limbs of patients with ALS, the CSA of the brachial plexus roots, trunks, and cords and the nT2 values of the brachial plexus trunks were significantly smaller than in the healthy controls. In the LGMs, the affected limbs of ALS showed significantly smaller CSA and higher FF than controls. The model containing parameters such as brachial plexus trunk CSA, subscapularis CSA, infraspinatus CSA, and subscapularis FF had excellent diagnostic efficacy for ALS. Additionally, increased subscapularis FF and supraspinatus FF were correlated with disease severity, and subscapularis CSA was negatively correlated with the clinical stage. DATA CONCLUSION: Brachial plexus thinning, LGM atrophy, and fatty infiltration might serve as MRI-derived biomarkers for ALS with upper extremity onset. LEVEL OF EVIDENCE: 4 TECHNICAL EFFICACY: Stage 2.

Experimental and Numerical Study of a Rebar-Prestressed Cylinder Concrete Pipe (RPCCP) under Internal Load.

In order to study the load-bearing failure characteristics of a RPCCP under internal load, a field prototype test was designed, and a finite element model was established. An internal load was applied up to 2.0 MPa step by step and the force variation law of each part was obtained. During the production of the RPCCP, by wrapping prestressed steel bars around the concrete core with a cylinder, the core was subjected to an initial precompression stress. In the loading process, the protective cover cracked first, from where the concrete core gradually changed from the initial compression state to a tension state, finally cracking from the inner and outer diameter. The stresses of the cylinder and steel bars increased steadily with the internal load and did not yield. The finite element calculation results were in good agreement with the test results, and the influence characteristics of the tension control stress of the steel bar and the concrete strength on the failure of the RPCCP under internal load were discussed. The results showed that the internal load of the protective cover was independent of the tension control stress, but decreases with a decrease in concrete strength, while the load corresponding to the concrete core entering plasticity is related to the tension control stress and the concrete strength, and the relationships were basically linear.

Complete sequence and comparative analysis of the mitochondrial genome of the rare and endangered Clematis acerifolia, the first clematis mitogenome to provide new insights into the phylogenetic evolutionary status of the genus.

Clematis is one of the large worldwide genera of the Ranunculaceae Juss. Family, with high ornamental and medicinal value. China is the modern distribution centre of Clematis with abundant natural populations. Due to the complexity and high morphological diversity of Clematis, the genus is difficult to classify systematically, and in particular, the phylogenetic position of the endangered Clematis acerifolia is highly controversial. The use of the mitochondrial complete genome is a powerful molecular method that is frequently used for inferring plants phylogenies. However, studies on Clematis mitogenome are rare, thus limiting our full understanding of its phylogeny and genome evolution. Here, we sequenced and annotated the C. acerifolia mt genome using Illumina short- and Nanopore long-reads, characterized the species first complete mitogenome, and performed a comparative phylogenetic analysis with its close relatives. The total length of the C. acerifolia mitogenome is 698,247 bp and the main structure is multi-branched (linear molecule 1 and circular molecule 2). We annotated 55 genes, including 35 protein-coding, 17 tRNA, and 3 rRNA genes. The C. acerifolia mitogenome has extremely unconserved structurally, with extensive sequence transfer between the chloroplast and mitochondrial organelles, sequence repeats, and RNA editing. The phylogenetic position of C. acerifolia was determined by constructing the species mitogenome with 24 angiosperms. Further, our C. acerifolia mitogenome characteristics investigation included GC contents, codon usage, repeats and synteny analysis. Overall, our results are expected to provide fundamental information for C. acerifolia mitogenome evolution and confirm the validity of mitochondrial analysis in determining the phylogenetic positioning of Clematis plants.

Mast Cell Tryptase Promotes Inflammatory Bowel Disease-Induced Intestinal Fibrosis.

BACKGROUND: Intestinal fibrosis is the final pathological outcome of chronic intestinal inflammation without specific therapeutic drugs, which leads to ileus and surgical intervention. Intestinal fibrosis is characterized by excessive deposition of extracellular matrix (ECM). The role of mast cells (MCs), which are members of the sentinel immune cell population, is unknown in intestinal fibrosis. METHODS: In this study, we analyzed changes in MCs, tryptase proteins, and ECM components in human fibrotic and control patient intestines. We constructed dextran sodium sulfate-induced intestinal fibrosis models using wild-type mice, MC-reconstituted mice, and MC-deficient mice to explore the role of MCs and tryptase in intestinal fibrosis. The roles and mechanisms of MCs and tryptase on fibroblasts were evaluated using human MCs (HMC-1 and LAD-2), commercial tryptase proteins, human colon fibroblasts (CCD-18Co fibroblasts), the tryptase inhibitor APC366, and the protease-activated receptor-2 (PAR-2) antagonist ENMD-1068. RESULTS: Regardless of whether the colon was a human colon or a mouse colon, the fibrotic intestinal tissue had increased MC infiltration and a higher expression of ECM proteins or genes than that of the control group. The dextran sodium sulfate-induced intestinal fibrosis in MC-deficient mice was alleviated compared with that in wild-type mice. After MC reconstruction in MC-deficient mice, the alleviating effect disappeared. Tryptase, as a content stored in MC granules, was released into fibrotic intestinal tissues in the form of degranulation, resulting in an increased expression of tryptase. Compared with the control group, the tryptase inhibition group (the APC366 group) had reduced intestinal fibrosis. The CCD-18Co fibroblasts, when cocultured with MCs or treated with tryptase proteins, were activated to differentiate into myofibroblasts and secrete more ECM proteins (such as collagen and fibronectin). The underlying mechanism of fibroblast activation by tryptase was the activation of the PAR-2/Akt/mTOR pathway. CONCLUSIONS: We found that MC tryptase promotes inflammatory bowel disease-induced intestinal fibrosis. The underlying mechanism is that tryptase promotes the differentiation of fibroblasts into fibrotic-phenotype myofibroblasts by activating the PAR-2/Akt/ mTOR pathway of fibroblasts.

Icariin Ameliorates Amyloid Pathologies by Maintaining Homeostasis of Autophagic Systems in Aß1-42-Injected Rats.

Macroautophagy, a sole pathway for dysfunctional organelles or aggregated proteins turnover, has been implicated in the early development of Alzheimer's disease (AD). Previous studies have found that reversal of autophagy dysfunction in APP transgenic mice ameliorates amyloid pathologies. Icariin (ICA), the main component from traditional Chinese herb Epimedium brevicornu Maxim., can reduce accumulations of amyloid-ß (Aß) peptide in vivo and in vitro, but the mechanism remains unclear. Here, we explored the effects of ICA on autophagy-lysosomal pathway in intracerebroventricular (icv) injection of human Aß1-42 peptide rats. We demonstrated that feeding the rats with ICA (30 mg/kg, 60 mg/kg and 90 mg/kg rat, per os) for 4 weeks rescued the Aß1-42-induced spatial memory impairments, reduced endogenous rat Aß42 tested by ELISA and decreased Aß accumulation using 6E10 antibody. Furthermore, Aß1-42 induced strong autophagy response, however ICA decreased the levels of microtubule-associated protein 1 light chain 3 (LC3) II/LC3I, Beclin1, Cathepsin D (Cat D) and brain lysosomal Cathepsin D activity. We also observed that ICA enhanced the phosphorylation of protein kinase B (PKB/AKT) and p70 ribosomal protein S6 kinase (p70S6K). In addition, ICA arrested Aß1-42-induced cells loss, mitochondrias damage, nuclear membranes unclear and abundant nucleas chromatin agglutinates in hippocampus, lessened the expression of Cleaved-caspase-3, brain oxidative stress, astroglial activation. These findings suggest that ICA can ameliorate amyloid pathologies with improving autophagy-lysosome function and Chinese materia medica may be potential for AD treatment.

NGF promotes long-term memory formation by activating poly(ADP-ribose)polymerase-1.

Nerve growth factor (NGF) is a critical secreted protein that plays an important role in development, survival, and function of the mammalian nervous system. Previously reports suggest that endogenous NGF is essential for the hippocampal plasticity/memory and NGF deprivation induces the impairment of hippocampus-related memory and synaptic plasticity. However, whether exogenous supplement of NGF could promote the hippocampus-dependent synaptic plasticity/memory and the possible underlying mechanisms are not clear. In this study we found that NGF administration facilitates the hippocampus-dependent long-term memory and synaptic plasticity by increasing the activity of PARP-1, a polymerase mediating the PolyADP-ribosylation and important for the memory formation. Co-application of 3-Aminobenzamide (3-AB), a specific inhibitor of PARP-1, distinctly blocked the boosting effect of NGF on memory and synaptic plasticity, and the activation of downstream PKA-CREB signal pathway. Our data provide the first evidence that NGF supplement facilitates synaptic plasticity and the memory ability through PARP-1-mediated protein polyADP-ribosylation and activation of PKA-CREB pathway.

Glycogen synthase kinase-3ß regulates leucine-309 demethylation of protein phosphatase-2A via PPMT1 and PME-1.

Protein phosphatase-2A (PP2A) activity is significantly suppressed in Alzheimer's disease. We have reported that glycogen synthase kinase-3ß (GSK-3ß) inhibits PP2A via upregulating the phosphorylation of PP2A catalytic subunit (PP2A(C)). Here we studied the effects of GSK-3ß on the inhibitory demethylation of PP2A at leucine-309 (dmL309-PP2A(C)). We found that GSK-3ß regulates dmL309-PP2A(C) level by regulating PME-1 and PPMT1. Knockdown of PME-1 or PPMT1 eliminated the effects of GSK-3ß on PP2A(C). GSK-3 could negatively regulate PP2A regulatory subunit protein level. We conclude that GSK-3ß can inhibit PP2A by increasing the inhibitory L309-demethylation involving upregulation of PME-1 and inhibition of PPMT1.

Glycogen synthase kinase-3ß regulates Tyr307 phosphorylation of protein phosphatase-2A via protein tyrosine phosphatase 1B but not Src.

GSK-3ß (glycogen synthase kinase-3ß), a crucial tau kinase, negatively regulates PP2A (protein phosphatase 2A), the most active tau phosphatase that is suppressed in the brain in AD (Alzheimer's disease). However, the molecular mechanism is not understood. In the present study we found that activation of GSK-3ß stimulates the inhibitory phosphorylation of PP2A at Tyr307 (pY307-PP2A), whereas inhibition of GSK-3ß decreased the level of pY307-PP2A both in vitro and in vivo. GSK-3ß is a serine/threonine kinase that can not phosphorylate tyrosine directly, therefore we measured PTP1B (protein tyrosine phosphatase 1B) and Src (a tyrosine kinase) activities. We found that GSK-3ß can modulate both PTP1B and Src protein levels, but it only inhibits PTP1B activity, with no effect on Src. Furthermore, only knockdown of PTP1B but not Src by siRNA (small interfering RNA) eliminates the effects of GSK-3ß on PP2A. GSK-3ß phosphorylates PTP1B at serine residues, and activation of GSK-3ß reduces the mRNA level of PTP1B. Additionally, we also observed that GSK-3 negatively regulates the protein and mRNA levels of PP2A, and knockdown of CREB (cAMP-response-element-binding protein) abolishes the increase in PP2A induced by GSK-3 inhibition. The results of the present study suggest that GSK-3ß inhibits PP2A by increasing the inhibitory Tyr307 phosphorylation and decreasing the expression of PP2A, and the mechanism involves inhibition of PTP1B and CREB.

Acetyl-L-carnitine attenuates okadaic acid induced tau hyperphosphorylation and spatial memory impairment in rats.

Tau hyperphosphorylation and memory deficit are characteristic alterations of Alzheimer's disease (AD). Protein phosphatases (PP) 2A plays a crucial role in AD-like lesions. Inhibition of PP2A through hippocampal injection of okadaic acid (OA) induces tau hyperphosphorylation and memory impairment of rats. By using this model, we explored in the present study the effects of acetyl-L-carnitine (ALCAR), a constituent of the inner mitochondrial membrane, on the memory retention, tau phosphorylation, and oxidative stress in rats. We found that pre-treatment of ALCAR (50 mg/d . rat, per os) for two weeks efficiently improved the OA-induced spatial memory retention impairment of the rats. ALCAR antagonized tau hyperphosphorylation at multiple AD sites and it abated the OA-induced PP2A inhibition and oxidative stress. Our study provides the first in vivo evidence that ALCAR can attenuate AD-like PP2A inhibition, tau hyperphosphorylation, and spatial memory deficit of the rats. It suggests that ALCAR may hold potential in AD treatment.

Activation of glycogen synthase kinase-3 inhibits long-term potentiation with synapse-associated impairments.

Activation of glycogen synthase kinase-3 (GSK-3) can cause memory deficits as seen in Alzheimer's disease, the most common age-associated dementia, but the mechanism is not understood. Here, we found that activation of GSK-3 by wortmannin or transient overexpression of wild-type GSK-3beta could suppress the induction of long-term potentiation (LTP) in rat hippocampus, whereas simultaneous inhibition of GSK-3 by lithium or SB216763 or transient expression of a dominant-negative GSK-3beta mutant (dnGSK-3beta) preserved the LTP. After high-frequency stimulation (HFS), the presynaptic release of glutamate and the expression/clustering of synapsin I, a synaptic vesicle protein playing an important role in neurotransmitter release, decreased markedly after upregulation of GSK-3. In vitro studies further demonstrated that GSK-3 inhibited the expression of SynI independent of HFS. In postsynaptic level, the expression of PSD93 and NR2A/B proteins decreased significantly when GSK-3 was activated. The LTP-associated synapse impairments including less presynaptic active zone, thinner postsynaptic density, and broader synaptic cleft were also prominent in the hippocampal slices after HFS with activation of GSK-3. These synaptic impairments were attenuated when GSK-3 was simultaneously inhibited by LiCl or SB216763 or transient expression of dnGSK-3. We conclude that upregulation of GSK-3 impairs the synaptic plasticity both functionally and structurally, which may underlie the GSK-3-involved memory deficits.