scholarly journals BAG3 and SYNPO (synaptopodin) facilitate phospho-MAPT/Tau degradation via autophagy in neuronal processes

2019 ◽  
Author(s):  
Changyi Ji ◽  
Maoping Tang ◽  
Claudia Zeidler ◽  
Jörg Höhfeld ◽  
Gail VW Johnson
Keyword(s):  
Receptor Protein ◽  
Autophagic Flux ◽  
Catabolic Pathway ◽  
Protein Tau ◽  
Sequestosome 1 ◽  
Cytoskeleton Protein ◽  
Neuronal Processes ◽  
Mature Neurons ◽  
First Time

AbstractA major cellular catabolic pathway in neurons is macroautophagy/autophagy, through which misfolded or aggregation-prone proteins are sequestered into autophagosomes that fuse with lysosomes, and are subsequently degraded. MAPT (microtubule associated protein tau) is one of the protein clients of autophagy. Given that accumulation of hyperphosphorylated MAPT contributes to the pathogenesis of Alzheimer disease and other tauopathies, decreasing endogenous MAPT levels has been shown to be beneficial to neuronal health in models of these diseases. A previous study demonstrated that the HSPA/HSP70 co-chaperone BAG3 (BCL2 associated athanogene 3) facilitates endogenous MAPT clearance through autophagy. These findings prompted us to further investigate the mechanisms underlying BAG3-mediated autophagy in the degradation of endogenous MAPT. Here we demonstrate for the first time that BAG3 plays an important role in autophagic flux in the neuritic processes of mature neurons (20-24 days in vitro [DIV]) through interaction with the post-synaptic cytoskeleton protein SYNPO (synaptopodin). Loss of either BAG3 or SYNPO impeded the fusion of autophagosomes and lysosomes predominantly in the post-synaptic compartment. A block of autophagy leads to accumulation of the autophagic receptor protein SQSTM1/p62 (sequestosome 1) as well as MAPT phosphorylated at Ser262 (p-Ser262). Furthermore, p-Ser262 appears to accumulate in autophagosomes at post-synaptic densities. Overall these data provide evidence of a novel role for the co-chaperone BAG3 in synapses. In cooperation with SYNPO, it functions as part of a surveillance complex that facilitates the autophagic clearance of MAPT p-Ser262, and possibly other MAPT species at the post-synapse. This appears to be crucial for the maintenance of a healthy, functional synapse.

scholarly journals SPINK1-induced amelioration of impaired autophagy contributes to suppression of trypsinogen activation in a model of acute pancreatitis

2020 ◽  
Author(s):  
Yuxiao Zhao ◽  
Jianlong Jia ◽  
Abdullah Shopit ◽  
Yang Liu ◽  
Jun Wang
Keyword(s):  
Acute Pancreatitis ◽  
In Vitro Model ◽  
Autophagic Flux ◽  
Trypsin Activity ◽  
Autophagy Flux ◽  
Trypsinogen Activation ◽  
Vitro Model ◽  
First Time ◽  
Induced Amelioration

AbstractSPINK1 has been regarded as a reversible trypsinogen inhibitor for the inappropriate activation of trypsin, a key step in the initiation of acute pancreatitis (AP). However, the mechanisms of its action remains largely unclear and controversial. Here, we reported an unexpected effects of SPINK1 on inhibiting trypsinogen activation through the regulation of impaired autophagy in cerulein-stimulated AR42J cells, a well-established in vitro model of acute pancreatitis. Firstly, we found that the impaired autophagic flux was induced and trypsinogen activity enhanced in the above setting. Then, we showed that SPINK1 overexpression could inhibit the level of increased autophagic activity, improving the hindered autophagy flux, and significantly decreased the trypsinogen activity, whereas shRNA-caused downregulation of SPINK1 exacerbated the impairment of autophagic flux and trypsin activity, in the same cerulein-processed cells. More importantly, the trypsinogen activation in this model could be ameliorated by 3-Methyladenine(3-MA), an autophagy inhibitor. Thus, this study revealed, possibly for the first time, that SPINK1 greatly blocked the trypsinogen activation possibly through the modulation of impaired autophagy in cerulein-induced in vitro model of acute pancreatitis.

scholarly journals Unraveling the 17β-Estradiol Degradation Pathway in Novosphingobium tardaugens NBRC 16725

2020 ◽  
Vol 11 ◽  
Author(s):  
Juan Ibero ◽  
Beatriz Galán ◽  
Virginia Rivero-Buceta ◽  
José L. García
Keyword(s):  
Degradation Pathway ◽  
Site Directed Mutagenesis ◽  
Receptor Protein ◽  
Catabolic Pathway ◽  
Degrading Bacterium ◽  
Catabolic Genes ◽  
Steroid Transport ◽  
17Β Estradiol ◽  
The Common ◽  
First Time

We have analyzed the catabolism of estrogens in Novosphingobium tardaugens NBRC 16725, which is able to use endocrine disruptors such as 17β-estradiol, estrone, and estriol as sole carbon and energy sources. A transcriptomic analysis enabled the identification of a cluster of catabolic genes (edc cluster) organized in two divergent operons that are involved in estrogen degradation. We have developed genetic tools for this estrogen-degrading bacterium, allowing us to delete by site-directed mutagenesis some of the genes of the edc cluster and complement them by using expression plasmids to better characterize their precise role in the estrogen catabolism. Based on these results, a catabolic pathway is proposed. The first enzyme of the pathway (17β-hydroxysteroid dehydrogenase) used to transform 17β-estradiol into estrone is encoded out of the cluster. A CYP450 encoded by the edcA gene performs the second metabolic step, i.e., the 4-hydroxylation of estrone in this strain. The edcB gene encodes a 4-hydroxyestrone-4,5-dioxygenase that opens ring A after 4-hydroxylation. The initial steps of the catabolism of estrogens and cholate proceed through different pathways. However, the degradation of estrogens converges with the degradation of testosterone in the final steps of the lower catabolic pathway used to degrade the common intermediate 3aα-H-4α(3′-propanoate)7a-β-methylhexahydro-1,5-indanedione (HIP). The TonB-dependent receptor protein EdcT appears to be involved in estrogen uptake, being the first time that this kind of proteins has been involved in steroid transport.

scholarly journals Vaspin Alleviates Pathological Cardiac Hypertrophy By Regulating Autophagy-Dependent Myocardial Senescence

2020 ◽  
Author(s):  
Haiying Rui ◽  
Ruochuan Li ◽  
Lulu Liu ◽  
Ziqi Han ◽  
Huaxiang Yu ◽  
...  
Keyword(s):  
Cardiac Hypertrophy ◽  
Kinase Inhibitors ◽  
Subcutaneous Administration ◽  
Autophagic Flux ◽  
Protective Effects ◽  
Myocardial Cells ◽  
Ischaemia Reperfusion Injury ◽  
Pathological Cardiac Hypertrophy ◽  
First Time

Abstract Background: Visceral adipose tissue derived serine protease inhibitor (vaspin), a secretory adipokine, was reported to play a protective role in insulin resistance. Recent studies have demonstrated that serum vaspin levels are downregulated in patients with coronary artery disease (CAD) and that vaspin has a protective effect on myocardial ischaemia/reperfusion injury (IRI) and atherosclerosis. However, whether vaspin exerts specific effects on pathological cardiac hypertrophy remains unknown.Methods: Pathologic cardiac hypertrophy was induced in male C57BL/6J wild type (WT) and vaspin knockout (vaspin ko) mice. Buparlisib (PI3K inhibitor, 50 mg/kg), rapamycin (mTOR inhibitor, 20 mg/kg), or A 769662 (AMPK agonist, 30 mg/kg) wer e pre and co administered to vaspin ko mice daily for a period of 15 days. Induction of pathological cardiac hypertrophy was performed by the subcutaneous administration of isoproterenol (ISO) (5 mg/kg) into mice from the 7th to the 15th day. Cardiac hype rtrophy, fibrosis, and cardiac function were examined in these mice. Critical characteristics of senescence (senescence associated β galactosidase activity and expression of cyclin dependent kinase inhibitors) were examined in the cardiac hypertrophy modelResults: We provide the first evidence that the serum level of vaspin decreased during pathological cardiac hypertrophy; further, knocking out of vaspin resulted in markedly exaggerated cardiac h ypertrophy and fibrosis, and increased cardiomyocyte senesc senescence in mice treated with ISO. Conversely, the administration of exogenous ence in mice treated with ISO. Conversely, the administration of exogenous recombinant human vaspin in vitro protected myocardial cells against hypertrophy recombinant human vaspin in vitro protected myocardial cells against hypertrophy and senescence caused by ISO. and senescence caused by ISO. MechanisticallyMechanistically, PI3K, PI3K--AKTAKT--mTOR mTOR pathwaypathway--dependent activation of autophadependent activation of autophagic flux was involved in the protective gic flux was involved in the protective effects of vaspin toward cardiac hypertrophy.effects of vaspin toward cardiac hypertrophy.Conclusion: Our results showed for the first time that vaspin functions as a critical Our results showed for the first time that vaspin functions as a critical regulator that alleviates pathological cardiac hypertrophy by regulating regulator that alleviates pathological cardiac hypertrophy by regulating autophagyautophagy--ddependent myocardial senescence, which provides potential preventive and ependent myocardial senescence, which provides potential preventive and therapeutic targets for pathological cardiac hypertrophy.therapeutic targets for pathological cardiac hypertrophy.

scholarly journals The PaaX Repressor, a Link between Penicillin G Acylase and the Phenylacetyl-Coenzyme A Catabolon of Escherichia coli W

2004 ◽  
Vol 186 (7) ◽  
pp. 2215-2220 ◽  
Author(s):  
Beatriz Galán ◽  
José L. García ◽  
María A. Prieto
Keyword(s):  
Escherichia Coli ◽  
Coenzyme A ◽  
Regulatory Mechanism ◽  
Penicillin G Acylase ◽  
Receptor Protein ◽  
Penicillin G ◽  
Catabolic Pathway ◽  
Gene Encoding ◽  
Unusual Position

ABSTRACT The pac gene, encoding the penicillin G acylase from Escherichia coli W, is regulated by the PaaX repressor of the phenylacetate catabolic pathway. pac expression depends on the synthesis of phenylacetyl-coenzyme A. PaaX and the cyclic AMP receptor protein (CRP) bind in vitro to the Ppac promoter region. A palindromic sequence proposed as the PaaX operator is located upstream of the −35 box overlapping a CRP binding site, an unusual position that suggests a novel regulatory mechanism.

scholarly journals Spermidine induces cytoprotective autophagy of female germline stem cells in vitro and ameliorates aging caused by oxidative stress through upregulated sequestosome-1/p62 expression

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xiaoyan Yuan ◽  
Geng. G. Tian ◽  
Xiuying Pei ◽  
Xiaopeng Hu ◽  
Ji Wu
Keyword(s):  
Oxidative Stress ◽  
Stem Cells ◽  
Protein Expression ◽  
Cellular Senescence ◽  
Critical Role ◽  
Autophagic Flux ◽  
Germline Stem Cells ◽  
Sequestosome 1 ◽  
Female Germline

Abstract Background Autophagy is required for oogenesis and plays a critical role in response to aging caused by oxidative stress. However, there have been no reports on regulation of cytoprotective autophagy in female germline stem cells (FGSCs) in response to aging caused by oxidative stress. Results We found that Spermidine (SPD) significantly increased protein expression of autophagy markers microtubule-associated protein 1 light chain 3 beta-II (MAP1LC3B-II/LC3B-II) and sequestosome-1/p62 (SQSTM1/p62), and evoked autophagic flux in FGSCs. Moreover, SPD increased the number and viability of FGSCs in vitro. Further, we found that SPD significantly reduced basal or hydrogen peroxide (H2O2)-induced up-regulated protein expression of the aging markers, cyclin dependent kinase inhibitor 2A (p16/CDKN2A) and tumor protein 53 (p53). After knockdown of p62 in FGSCs, p16 protein levels were significant higher compared with controls. However, protein p16 levels were not significantly changed in p62 knockdown FGSCs with SPD treatment compared with without SPD. Moreover, SPD significantly changed the expression of autophagy-related genes and pathways in FGSCs, as shown by bioinformatics analysis of RNA sequencing data. Additionally, SPD significantly inhibited AKT/mTOR phosphorylation. Conclusions SPD induces cytoprotective autophagy in FGSCs in vitro and ameliorates cellular senescence of FGSCs induced by H2O2. Furthermore, SPD can ameliorate cellular senescence of FGSCs through p62. SPD might induce autophagy in FGSCs via the PI3K/Akt pathway. Our findings could be helpful for delaying aging of female germ cells due to oxidative stress and preserving female fertility.

Somatic Embryogenesis and In vitro Plant Regeneration in Vigna trilobata (L.) Verd. - A Potential Pasture Legume

1970 ◽  
Vol 19 (1) ◽  
pp. 89-99
Author(s):  
K. Choudhary ◽  
M. Singh ◽  
M. S. Rathore ◽  
N. S. Shekhawat
Keyword(s):  
Somatic Embryogenesis ◽  
Growth Regulators ◽  
Somatic Embryos ◽  
Basal Medium ◽  
Long Term Study ◽  
Continuous Application ◽  
First Time ◽  
Pasture Legume

This long term study demonstrates for the first time that it is possible to propagate embryogenic Vigna trilobata and to subsequently initiate the differentiation of embryos into complete plantlets. Initiation of callus was possible on 2,4-D. Somatic embryos differentiated on modified MS basal nutrient medium with 1.0 mg/l  of 2,4-D and 0.5 mg/l  of Kn. Sustained cell division resulted in globular and heart shape stages of somatic embryos. Transfer of embryos on to a fresh modified MS basal medium with 0.5 mg/l of Kn and 0.5 mg/l of GA3 helped them to attain maturation and germination. However, the propagation of cells, as well as the differentiation of embryos, were inhibited by a continuous application of these growth regulators. For this reason, a long period on medium lacking these growth regulators was necessary before the differentiation of embryos occurred again. The consequences for improving the propagation of embryogenic cultures in Vigna species are discussed. Key words: Pasture  legume, Vigna trilobata, Globular, Heart shape, somatic embryogenesis D.O.I. 10.3329/ptcb.v19i1.4990 Plant Tissue Cult. & Biotech. 19(1): 89-99, 2009 (June)

Dwindling status of Epimedium Elatum (Morren & Decne) and its geographical distribution in Kashmir Himalaya, India

2018 ◽  
pp. 47-52
Keyword(s):  
Medicinal Plant ◽  
Biological Activities ◽  
Conservation Status ◽  
Natural Populations ◽  
Culture Techniques ◽  
Kashmir Himalayas ◽  
Near Future ◽  
First Time ◽  
Tissue Culture Techniques

Epimedium elatum (Morren & Decne) of family Berberidaceace is a rare perennial medicinal plant, endemic to high altitude forests of Northwestern Himalayas in India. Ethnobotanically, it has been used as an ingredient for treatment of bone-joint disorders, impotence and kidney disorders in Kashmir Himalayas. Phytochemically, it is rich in Epimedin ABC and Icariin; all of these have been demonstrated to possess remarkable biological activities like PDE-5 inhibition (treatment of erectile dysfunction), anticancer, antiosteoporosis antioxidant and antiviral properties. The present investigation reports its traditional usage, comprehensive distribution and conservation status from twenty ecogeographical regions in Kashmir Himalayas, India. The species was reported from Gurez valley for the first time. Numerous threats like excessive grazing, deforestration, habitat fragmentation, tourism encroachment, landslides and excessive exploitation have decreased its natural populations in most of the surveyed habitats. Consequently, its existence may become threatened in near future if timely conservation steps are not taken immediately by concerned stakeholders involved in medicinal plant research. Moreover, use of plant tissue culture techniques is recommended for development of its in vitro propagation protocols. Therefore, introduction of this medicinal plant in botanical gardens, protected sites and development of monitoring programmes are needed for its immediate conservation in Northwestern Himalayas, India.

First Fluorescent Acetylspermidine Deacetylation Assay for HDAC10 Identifies Inhibitors of Neuroblastoma Cell Colony Growth That Increase Lysosome Accumulation

2020 ◽  
Author(s):  
Daniel Herp ◽  
Johannes Ridinger ◽  
Dina Robaa ◽  
Stephen A. Shinsky ◽  
Karin Schmidtkunz ◽  
...  
Keyword(s):  
Histone Deacetylases ◽  
High Throughput Screening ◽  
Neuroblastoma Cell ◽  
Hdac Inhibitors ◽  
Anticancer Therapy ◽  
Colony Growth ◽  
Autophagic Flux ◽  
Enzymatic Conversion ◽  
Lysine Deacetylase

Histone deacetylases (HDACs) are important epigenetic regulators involved in many diseases, esp. cancer. First HDAC inhibitors have been approved for anticancer therapy and many are in clinical trials. Among the 11 zinc-dependent HDACs, HDAC10 has received relatively little attention by drug discovery campaigns, despite its involvement e.g. in the pathogenesis of neuroblastoma. This is due in part to a lack of robust enzymatic conversion assays. In contrast to the protein lysine deacetylase and deacylase activity of the other HDAC subtypes, it has recently been shown that HDAC10 has strong preferences for deacetylation of oligoamine substrates like spermine or spermidine. Hence, it also termed a polyamine deacetylase (PDAC). Here, we present the first fluorescent enzymatic conversion assay for HDAC10 using an aminocoumarin labelled acetyl spermidine derivative to measure its PDAC activity, which is suitable for high-throughput screening. Using this assay, we identified potent inhibitors of HDAC10 mediated spermidine deacetylation in-vitro. Among those are potent inhibitors of neuroblastoma colony growth in culture that show accumulation of lysosomes, implicating disturbance of autophagic flux.

Structure-Reactivity Relationships on Substrates and Inhibitors of the Lysine Deacylase Sirtuin 2 from Schistosoma Mansoni (SmSirt2)

2019 ◽  
Author(s):  
Daria Monaldi ◽  
Dante Rotili ◽  
Julien Lancelot ◽  
Martin Marek ◽  
Nathalie Wössner ◽  
...  
Keyword(s):  
Schistosoma Mansoni ◽  
Human Cancer ◽  
Egg Laying ◽  
Human Cancer Cells ◽  
Parasite Survival ◽  
Survival And Reproduction ◽  
Emergence Of Resistance ◽  
First Time ◽  
Parasitic Life Cycle

The only drug for treatment of Schistosomiasis is Praziquantel, and the possible emergence of resistance makes research on novel therapeutic agents necessary. Targeting of Schistosoma mansoni epigenetic enzymes, which regulate the parasitic life cycle, emerged as promising approach. Due to the strong effects of human Sirtuin inhibitors on parasite survival and reproduction, Schistosoma sirtuins were postulated as therapeutic targets. In vitro testing of synthetic substrates of S. mansoni Sirtuin 2 (SmSirt2) and kinetic experiments on a myristoylated peptide demonstrated lysine long chain deacylation as an intrinsic SmSirt2 activity for the first time. Focused in vitro screening of the GSK Kinetobox library and structure-activity relationships (SAR) of identified hits, led to the first SmSirt2 inhibitors with activity in the low micromolar range. Several SmSirt2 inhibitors showed potency against both larval schistosomes (viability) and adult worms (pairing, egg laying) in culture without general toxicity to human cancer cells.<br>

α-Glucosidase Inhibition and Docking Studies of 5-Deoxyflavonols and Dihydroflavonols Isolated from Abutilon pakistanicum

2019 ◽  
Vol 23 (17) ◽  
pp. 1857-1866
Author(s):  
Munawar Hussain ◽  
Zaheer Ahmed ◽  
Shamsun N. Khan ◽  
Syed A. A. Shah ◽  
Rizwana Razi ◽  
...  
Keyword(s):  
Methanolic Extract ◽  
Docking Studies ◽  
Hydroxyl Group ◽  
Coumaric Acid ◽  
In Vitro Activity ◽  
Aerial Parts ◽  
First Time ◽  
Acid Esters ◽  
Phenol Moiety

Three new 5-deoxyflavonoid and dihydroflavonoids 2, 3 and 4 have been isolated from the methanolic extract of Abutioln pakistanicum aerial parts, for which structures were elucidated explicitly by extensive MS- and NMR-experiments. In addition to these, 3,7,4′-trihydroxy-3′-methoxy flavonol (1) is reported for the first time from Abutioln pakistanicum. Compound 2 and 4 are p-coumaric acid esters while compounds 2–4 exhibited α-glucosidase inhibitory activity. Docking studies indicated that the ability of flavonoids 2, 3 and 4 to form multiple hydrogen bonds with catalytically important residues is decisive hence is responsible for the inhibition activity. The docking results signified the observed in-vitro activity quite well which is in accordance with previously obtained conclusion that phenol moiety and hydroxyl group are critical for the inhibition of α-glucosidase enzyme.

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