The 26S proteasome, a self-compartmentalized protease complex, plays a crucial role in protein quality control. Multiple levels of regulatory systems modulate proteasomal activity for substrate ...hydrolysis. However, the destruction mechanism of mammalian proteasomes is poorly understood. We found that inhibited proteasomes are sequestered into the insoluble aggresome via HDAC6- and dynein-mediated transport. These proteasomes colocalized with the autophagic receptor SQSTM1 and cleared through selective macroautophagy, linking aggresomal segregation to autophagic degradation. This proteaphagic pathway was counter-balanced with the recovery of proteasomal activity and was critical for reducing cellular proteasomal stress. Changes in associated proteins and polyubiquitylation on inhibited 26S proteasomes participated in the targeting mechanism to the aggresome and autophagosome. The STUB1 E3 Ub ligase specifically ubiquitylated purified human proteasomes in vitro, mainly via Lys63-linked chains. Genetic and chemical inhibition of STUB1 activity significantly impaired proteasome processing and reduced resistance to proteasomal stress. These data demonstrate that aggresomal sequestration is the crucial upstream event for proteasome quality control and overall protein homeostasis in mammals.
Full text
Available for:
BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
Solid oxide cells (SOCs) are mutually convertible energy devices capable of generating electricity from chemical fuels including hydrogen in the fuel cell mode and producing green hydrogen using ...electricity from renewable but intermittent solar and wind resources in the electrolysis cell mode. An effective approach to enhance the performance of SOCs at reduced temperatures is by developing highly active oxygen electrodes for both oxygen reduction and oxygen evolution reactions. Herein, highly conductive Sm3+ and Nd3+ double-doped ceria (Sm0.075Nd0.075Ce0.85O2−δ, SNDC) is utilized as an active component for reversible SOC applications. We develop a novel La0.6Sr0.4Co0.2Fe0.8O3 −δ (LSCF)–SNDC composite oxygen electrode. Compared with the conventional LSCF–Gd-doped ceria oxygen electrode, the LSCF–SNDC exhibits ∼35% lower cathode polarization resistance (0.042 Ω cm2 at 750 °C) owing to rapid oxygen incorporation and surface diffusion kinetics. Furthermore, the SOC with the LSCF–SNDC oxygen electrode and the SNDC buffer layer yields a remarkable performance in both the fuel cell (1.54 W cm–2 at 750 °C) and electrolysis cell (1.37 A cm–2 at 750 °C) modes because the incorporation of SNDC promotes the surface diffusion kinetics at the oxygen electrode bulk and the activity of the triple phase boundary at the interface. These findings suggest that the highly conductive SNDC material effectively enhances both oxygen reduction and oxygen evolution reactions, thus serving as a promising material in reversible SOC applications at reduced temperatures.
Full text
Available for:
IJS, KILJ, NUK, PNG, UL, UM
PURPOSETo investigate the usefulness and ergonomics of a newly developed robotic system for flexible ureteroscopy (easyUretero). MATERIALS AND METHODSDuring in vitro testing, six participants ...performed renal stone removal four times in an artificial kidney-ureter-bladder model. Each participant manipulated a single-use digital flexible ureteroscope (LithoVue) with their hands and the robotic system, sequentially. We compared the task completion times of each participant. The ergonomics of and operational satisfaction with each procedure were assessed by questionnaires. In vivo tests evaluated the operability and safety of the robotic system in two live female pigs. We checked that all the steps of flexible lithotomy for renal stones could be completed individually. RESULTSThe task completion time with the robotic system during in vitro testing was significantly longer than with manual ureteroscopy regardless of the operator's competence level (expert professors: 282.6±92.4 seconds vs. 73.6±43.3 seconds, p<0.001; fellows: 247.5±57.7 seconds vs. 95.8±43.7 seconds, p<0.001; residents: 281.3±111.0 seconds vs. 188.6±138.6 seconds, p<0.001). The residents took more time to remove the upper and mid caliceal stones with the robotic system. The ergonomic evaluation was better for the robotic system, but operational satisfaction was lower, and there was no statistical difference among the groups. In vivo tests showed that all the steps of robotic flexible ureteroscopy could be completed without difficulty. No safety issues were encountered during the procedure. CONCLUSIONSThe robotic system (easyUretero) was ergonomic and safe for flexible ureteroscopy and laser lithotripsy for renal stones.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
To evaluate the effects of different hysterectomies-simple hysterectomy (SH) and radical hysterectomy (RH) with or without radiation therapy (RT) on urodynamics and lower urinary tract symptoms ...(LUTS).
Among patients who underwent urodynamic study between 2009 and 2019, those with RH history due to cervical cancer and SH for uterine myoma were included. Clinical parameters were compared after adjusting clinically significant baseline variables with multivariate regression.
A total of 289 patients (RH-only, n=57; RH+RT, n=72; SH, n=160) were included. Age at hysterectomy, gap between urodynamic study and hysterectomy, body mass index, hypertension and vaginal delivery history were adjusted. Stress urinary incontinence was more likely to occur in SH group (p<0.001), while urgency urinary incontinence was more prevalent in patients with history of RH (odds ratio OR 6.4, 95% confidence interval 2.171-18.855; p=0.001). There was no difference in OR of mixed urinary incontinence. Higher proportion of RH patients complained of recurrent urinary tract infection and voiding symptoms requiring intermittent catheterization. On urodynamic study, RH groups had lower maximal flow rate, larger post-void residual, decreased bladder sensation and impaired detrusor contractility (all p<0.001) than SH group. Adjuvant RT resulted in decreased compliance and decrease in volume of the first sense to void.
Predominant LUTS differed among patients after different types of hysterectomy. RH resulted in inefficient bladder emptying, leading to recurrent urinary tract infection and voiding symptoms requiring intermittent catheterization. Adjuvant RT exacerbated bladder compliance and increased bladder sensation.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The N-degron pathway is a proteolytic system in which the N-terminal degrons (N-degrons) of proteins, such as arginine (Nt-Arg), induce the degradation of proteins and subcellular organelles via the ...ubiquitin-proteasome system (UPS) or macroautophagy/autophagy-lysosome system (hereafter autophagy). Here, we developed the chemical mimics of the N-degron Nt-Arg as a pharmaceutical means to induce targeted degradation of intracellular bacteria via autophagy, such as Salmonella enterica serovar Typhimurium (S. Typhimurium), Escherichia coli, and Streptococcus pyogenes as well as Mycobacterium tuberculosis (Mtb). Upon binding the ZZ domain of the autophagic cargo receptor SQSTM1/p62 (sequestosome 1), these chemicals induced the biogenesis and recruitment of autophagic membranes to intracellular bacteria via SQSTM1, leading to lysosomal degradation. The antimicrobial efficacy was independent of rapamycin-modulated core autophagic pathways and synergistic with the reduced production of inflammatory cytokines. In mice, these drugs exhibited antimicrobial efficacy for S. Typhimurium, Bacillus Calmette-Guérin (BCG), and Mtb as well as multidrug-resistant Mtb and inhibited the production of inflammatory cytokines. This dual mode of action in xenophagy and inflammation significantly protected mice from inflammatory lesions in the lungs and other tissues caused by all the tested bacterial strains. Our results suggest that the N-degron pathway provides a therapeutic target in host-directed therapeutics for a broad range of drug-resistant intracellular pathogens.
Abbreviations: ATG: autophagy-related gene; BCG: Bacillus Calmette-Guérin; BMDMs: bone marrow-derived macrophages; CALCOCO2/NDP52: calcium binding and coiled-coil domain 2; CFUs: colony-forming units; CXCL: C-X-C motif chemokine ligand; EGFP: enhanced green fluorescent protein; IL1B/IL-1β: interleukin 1 beta; IL6: interleukin 6; LIR: MAP1LC3/LC3-interacting region; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; Mtb: Mycobacterium tuberculosis; MTOR: mechanistic target of rapamycin kinase; NBR1: NBR1 autophagy cargo receptor; OPTN: optineurin; PB1: Phox and Bem1; SQSTM1/p62: sequestosome 1; S. Typhimurium: Salmonella enterica serovar Typhimurium; TAX1BP1: Tax1 binding protein 1; TNF: tumor necrosis factor; UBA: ubiquitin-associated.
Full text
Available for:
BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
In the N-degron pathway, N-recognins recognize cognate substrates for degradation via the ubiquitin (Ub)-proteasome system (UPS) or the autophagy-lysosome system (hereafter autophagy). We have ...recently shown that the autophagy receptor SQSTM1/p62 (sequestosome 1) is an N-recognin that binds the N-terminal arginine (Nt-Arg) as an N-degron to modulate autophagic proteolysis. Here, we show that the N-degron pathway mediates pexophagy, in which damaged peroxisomal fragments are degraded by autophagy under normal and oxidative stress conditions. This degradative process initiates when the Nt-Cys of ACAD10 (acyl-CoA dehydrogenase family, member 10), a receptor in pexophagy, is oxidized into Cys sulfinic (Cys
O2
) or sulfonic acid (Cys
O3
) by ADO (2-aminoethanethiol (cysteamine) dioxygenase). Under oxidative stress, the Nt-Cys of ACAD10 is chemically oxidized by reactive oxygen species (ROS). The oxidized Nt-Cys2 is arginylated by ATE1-encoded R-transferases, generating the RC
OX
N-degron. RC
OX
-ACAD10 marks the site of pexophagy via the interaction with PEX5 and binds the ZZ domain of SQSTM1/p62, recruiting LC3
+
-autophagic membranes. In mice, knockout of either Ate1 responsible for Nt-arginylation or Sqstm1/p62 leads to increased levels of peroxisomes. In the cells from patients with peroxisome biogenesis disorders (PBDs), characterized by peroxisomal loss due to uncontrolled pexophagy, inhibition of either ATE1 or SQSTM1/p62 was sufficient to recover the level of peroxisomes. Our results demonstrate that the Cys-N-degron pathway generates an N-degron that regulates the removal of damaged peroxisomal membranes along with their contents. We suggest that tannic acid, a commercially available drug on the market, has a potential to treat PBDs through its activity to inhibit ATE1 R-transferases.
Abbreviations: ACAA1, acetyl-Coenzyme A acyltransferase 1; ACAD, acyl-Coenzyme A dehydrogenase; ADO, 2-aminoethanethiol (cysteamine) dioxygenase; ATE1, arginyltransferase 1; CDO1, cysteine dioxygenase type 1; ER, endoplasmic reticulum; LIR, LC3-interacting region; MOXD1, monooxygenase, DBH-like 1; NAC, N-acetyl-cysteine; Nt-Arg, N-terminal arginine; Nt-Cys, N-terminal cysteine; PB1, Phox and Bem1p; PBD, peroxisome biogenesis disorder; PCO, plant cysteine oxidase; PDI, protein disulfide isomerase; PTS, peroxisomal targeting signal; R-COX, Nt-Arg-CysOX; RNS, reactive nitrogen species; ROS, reactive oxygen species; SNP, sodium nitroprusside; UBA, ubiquitin-associated; UPS, ubiquitinproteasome system.
Full text
Available for:
BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
Central to the pathogenesis of nonalcoholic fatty liver disease (NAFLD) is the accumulation of lipids in the liver and various fat tissues. We aimed to elucidate the mechanisms by which lipid ...droplets (LDs) in the liver and adipocytes are degraded by the autophagy-lysosome system and develop therapeutic means to modulate lipophagy, i.e., autophagic degradation of LDs.
We monitored the process in which LDs are pinched off by autophagic membranes and degraded by lysosomal hydrolases in cultured cells and mice. The autophagic receptor p62/SQSTM-1/Sequestosome-1 was identified as a key regulator and used as a target to develop drugs to induce lipophagy. The efficacy of p62 agonists was validated in mice to treat hepatosteatosis and obesity.
We found that the N-degron pathway modulates lipophagy. This autophagic degradation initiates when the molecular chaperones including BiP/GRP78, retro-translocated from the endoplasmic reticulum, is N-terminally (Nt-) arginylated by ATE1 R-transferase. The resulting Nt-arginine (Nt-Arg) binds the ZZ domain of p62 associated with LDs. Upon binding to Nt-Arg, p62 undergoes self-polymerization and recruits LC3+ phagophores to the site of lipophagy, leading to lysosomal degradation. Liver-specific Ate1 conditional knockout mice under high fat diet developed severe NAFLD. The Nt-Arg was modified into small molecule agonists to p62 that facilitate lipophagy in mice and exerted therapeutic efficacy in obesity and hepatosteatosis of wild-type but not p62 knockout mice.
Our results show that the N-degron pathway modulates lipophagy and provide p62 as a drug target to treat NAFLD and other diseases related with metabolic syndrome.
Display omitted
•The N-degron pathway mediates lipophagy, i.e., the autophagic degradation of lipids.•The N-terminal arginine (Nt-Arg) conjugated by ATE1 binds p62 during lipophagy.•p62 bound by Nt-Arg recruit phagophores to lipid droplets for lysosomal hydrolysis.•Small molecule ligands to p62 were developed and demonstrated to induce lipophagy.•p62 agonists show robust efficacy in obesity and NAFLD without muscle loss.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPUK, ZAGLJ, ZRSKP
Solid oxide cells (SOCs) are mutually convertible energy devices capable of generating electricity from chemical fuels including hydrogen in the fuel cell mode and producing green hydrogen using ...electricity from renewable but intermittent solar and wind resources in the electrolysis cell mode. An effective approach to enhance the performance of SOCs at reduced temperatures is by developing highly active oxygen electrodes for both oxygen reduction and oxygen evolution reactions. Herein, highly conductive Sm
and Nd
double-doped ceria (Sm
Nd
Ce
O
, SNDC) is utilized as an active component for reversible SOC applications. We develop a novel La
Sr
Co
Fe
O
(LSCF)-SNDC composite oxygen electrode. Compared with the conventional LSCF-Gd-doped ceria oxygen electrode, the LSCF-SNDC exhibits ∼35% lower cathode polarization resistance (0.042 Ω cm
at 750 °C) owing to rapid oxygen incorporation and surface diffusion kinetics. Furthermore, the SOC with the LSCF-SNDC oxygen electrode and the SNDC buffer layer yields a remarkable performance in both the fuel cell (1.54 W cm
at 750 °C) and electrolysis cell (1.37 A cm
at 750 °C) modes because the incorporation of SNDC promotes the surface diffusion kinetics at the oxygen electrode bulk and the activity of the triple phase boundary at the interface. These findings suggest that the highly conductive SNDC material effectively enhances both oxygen reduction and oxygen evolution reactions, thus serving as a promising material in reversible SOC applications at reduced temperatures.
Full text
Available for:
IJS, KILJ, NUK, PNG, UL, UM
Thin sheets of V85Al10Co5 alloy were produced by a thermo-mechanical treatment consisting in successive hot rolling, cold rolling steps and annealing treatment at high temperature followed by either ...air cooling or water quenching. Though the values of hydrogen permeability measured for these sheets were significantly reduced as a consequence of the rolling process, the annealing treatment restored almost the hydrogen permeation properties to those of the alloy in the cast condition. EBSD analyses suggested that the post-annealing treatment performed at 1100 °C for 3 min after cold rolling induced a recrystallization of the grains resulting in a preferred orientation along the {002} planes. For the sample annealed and water quenched, the value of the hydrogen flux reached about 45 ml/cm2.min, which is more than twice the value of the flux obtained for thin foils of Pd alloys tested under identical conditions.
► Thin membranes of V–Al–Co alloy have been prepared by thermo-mechanical treatment. ► The hot and cold rolled alloys were annealed at high temperature for a short time. ► The hydrogen permeability shows a dependence on the cooling rate after annealing. ► Fast cooling rates induced by water quenching enhanced the hydrogen permeability. ► The study demonstrates the effect of low angle grain boundaries on these properties.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPUK
PDF
