A Zn-dependent structural transition of SOD1 modulates its ability to undergo phase separation.

The misfolding and mutation of Cu/Zn superoxide dismutase (SOD1) is commonly associated with amyotrophic lateral sclerosis (ALS). SOD1 can accumulate within stress granules (SGs), a type of membraneless organelle, which is believed to form via liquid-liquid phase separation (LLPS). Using wild-type, metal-deficient, and different ALS disease mutants of SOD1 and computer simulations, we report here that the absence of Zn leads to structural disorder within two loop regions of SOD1, triggering SOD1 LLPS and amyloid formation. The addition of exogenous Zn to either metal-free SOD1 or to the severe ALS mutation I113T leads to the stabilization of the loops and impairs SOD1 LLPS and aggregation. Moreover, partial Zn-mediated inhibition of LLPS was observed for another severe ALS mutant, G85R, which shows perturbed Zn-binding. By contrast, the ALS mutant G37R, which shows reduced Cu-binding, does not undergo LLPS. In addition, SOD1 condensates induced by Zn-depletion exhibit greater cellular toxicity than aggregates formed by prolonged incubation under aggregating conditions. Overall, our work establishes a role for Zn-dependent modulation of SOD1 conformation and LLPS properties that may contribute to amyloid formation.

Surgical interventions in female urethral strictures: a comprehensive literature review.

INTRODUCTION AND HYPOTHESIS: Female urethral stricture (FUS) is an uncommon entity. Although there is no clinical consensus on the best modality of treatment, several studies have been published describing different techniques of FUS management. We carried out a literature review of the different surgical techniques used in the management of FUS and their results. METHODS: We performed a systematic search of the PubMed and EMBASE databases and several cross-references. We grouped the data available from the studies into four general treatment categories. RESULTS: We reported 35 studies (488 patients) with outcome measures; 53.48% of cases were presumably idiopathic in origin. A history of prior intervention was described in 91.29% of cases. As a surgical intervention, urethral dilatation (UD) had the lowest success rate of only 41.25%. In contrast, local flaps performed better (92.54% success rate) than local or oral grafts (87.30% and 89.94%, respectively). Only 9.43% of patients experienced mild to moderate post-surgery de novo incontinence; most of them recovered with pelvic floor exercises. CONCLUSION: In practice, UD is tried first for FUS, at least once, before urethroplasty. In case of failure or short recurrence following UD, urethroplasty should not be delayed. In experienced hands, urethroplasty has a better outcome.

Investigating mitochondrial autophagy by routine transmission electron microscopy: Seeing is believing?

Mitochondrial autophagy is affected in many diseases. In the past few years, the multiple-steps process of selective degradation of mitochondria has been dissected in details by combining outcomes from different approaches. Perhaps one of the most rigorous methods to clearly visualise mitochondria undergoing autophagic engulfment and degradation, is transmission electron microscopy (TEM). In this opinion paper, we want to give a brief summary of the mitophagic process, and by which means mitophagy can be addressed, including TEM analysis. We will report examples of autophagy and mitophagy-related TEM images, and discuss how to decipher the different steps of the mitophagic process by routine TEM. In our opinion, this technique can be used as a powerful confirmatory approach for mitochondrial autophagy and can provide details of the organelle fate throughout the course of mitophagy with no substantial sample manipulation.

Asymmetric total syntheses of naturally occurring α,ß-enone-containing RALs, L-783290 and L-783277 through intramolecular base-mediated macrolactonization reaction.

Asymmetric total synthesis of two naturally occurring α,ß-enone containing RALs, L-783290 and L-783277 is described in this article. An E-selective Horner-Wadsworth-Emmons (HWE) olefination was used as a key reaction to construct the C7'-C8' olefinic unsaturation in L-783290. An enantiopure alkyne addition to the aldehyde followed by Z-selective partial reduction was employed to construct the C7'-C8' olefinic unsaturation in L-783277. Biomimetic lactonization reaction was used to construct the macrolactone core in both the target molecules.

Rate of anastomotic leak following right hemicolectomy by general surgical trainees.

PURPOSE: Performing a right hemicolectomy (RH) is a core technical competency for general surgical trainees. There is a concern that anastomotic leaks occur more frequently when patients are operated on by trainees rather than by surgeons. This study aims to analyse the quality of care outcomes after RH, stratified by the experience level of the operator. METHODS: Patients were retrospectively recruited from the Bi-National Colorectal Cancer Audit (BCCA) Registry, from 2007 to 2018. All patients who underwent a RH for colorectal cancer were eligible. The primary outcome measure was anastomotic leak rate. RESULTS: A total of 6548 eligible right hemicolectomies were identified, with 74% being performed by consultants, 12% by fellows, and 14% by surgical trainees. The overall incidence of an anastomotic leak was 2.1%, with the highest rate of 3.7% noted among supervised registrars. Positive resection margin rate was the highest among unsupervised trainees at 10.5%, as compared with 4.3% among consultants. Anastomotic leak, anastomotic bleeding, prolonged ileus, and pneumonia occurred significantly less frequently with consultant surgeons, as compared with trainees. Independent risk factors for anastomotic leak were urgent surgery, extended right hemicolectomy, conversion to open surgery, and a lower level of operator seniority. Two independent risk factors were identified for inpatient mortality-a high ASA score (III and above) and urgent surgery. CONCLUSION: RH is a common operative procedure in general surgical training. Data from this study may assist with the structuring of surgical training programmes, aimed at maximising both patient safety and trainee professional development and education.

Asymmetric total synthesis of paecilomycin C through intramolecular nucleophilic ring opening of an epoxide.

The convergent total synthesis of naturally occurring paecilomycin C is described here for the first time. Asymmetric Brown allylation, E-selective cross metathesis, and a biomimetic carboxylate assisted intramolecular nucleophilic ring opening of an epoxide were employed to access the enantiopure γ-lactone framework of the natural product. Late stage E-selective Julia-Kocienski olefination was then employed to furnish the natural product in an efficient way.

Regulation of ER-mitochondria contacts by Parkin via Mfn2.

Parkin, an E3 ubiquitin ligase and a Parkinson's disease (PD) related gene, translocates to impaired mitochondria and drives their elimination via autophagy, a process known as mitophagy. Mitochondrial pro-fusion protein Mitofusins (Mfn1 and Mfn2) were found to be a target for Parkin mediated ubiquitination. Mfns are transmembrane GTPase embedded in the outer membrane of mitochondria, which are required on adjacent mitochondria to mediate fusion. In mammals, Mfn2 also forms complexes that are capable of tethering mitochondria to endoplasmic reticulum (ER), a structural feature essential for mitochondrial energy metabolism, calcium (Ca2+) transfer between the organelles and Ca2+ dependent cell death. Despite its fundamental physiological role, the molecular mechanisms that control ER-mitochondria cross talk are obscure. Ubiquitination has recently emerged as a powerful tool to modulate protein function, via regulation of protein subcellular localization and protein ability to interact with other proteins. Ubiquitination is also a reversible mechanism, which can be actively controlled by opposing ubiquitination-deubiquitination events. In this work we found that in Parkin deficient cells and parkin mutant human fibroblasts, the tether between ER and mitochondria is decreased. We identified the site of Parkin dependent ubiquitination and showed that the non-ubiquitinatable Mfn2 mutant fails to restore ER-mitochondria physical and functional interaction. Finally, we took advantage of an established in vivo model of PD to demonstrate that manipulation of ER-mitochondria tethering by expressing an ER-mitochondria synthetic linker is sufficient to rescue the locomotor deficit associated to an in vivo Drosophila model of PD.

α-Viniferin, a dietary phytochemical, inhibits Monoamine oxidase and alleviates Parkinson's disease associated behavioral deficits in a mice model.

Parkinson's disease (PD) is one of the most prevalent age-related neurodegenerative disorders. Behavioral complexities worsen over time due to progressive dopaminergic (DArgic) neuronal loss at substantia nigra region of brain. Available treatments typically aim to increase dopamine (DA) levels at striatum. DA is degraded by Monoamine oxidase (MAO), thus dietary phytochemicals with MAO inhibitory properties can contribute to elevate DA levels and reduce the ailment. Characterization of naturally occurring dietary MAO inhibitors is inadequate. Based on available knowledge, we selected different classes of molecules and conducted a screening process to assess their potential as MAO inhibitors. The compounds mostly derived from food sources, broadly belonging to triterpenoids (ursane, oleanane and hopane), alkaloid, polyphenolics, monoterpenoids, alkylbenzene, phenylpropanoid and aromatic alcohol classes. Among all the molecules, highest level of MAO inhibition is offered by α-viniferin, a resveratrol trimer. Cell viability, mitochondrial morphology and reactive oxygen species (ROS) generation remained unaltered by 50 µM α-viniferin treatment in-vitro. Toxicity studies in Drosophila showed unchanged gross neuronal morphology, ROS level, motor activity or long-term survival. α-Viniferin inhibited MAO in mice brain and elevated striatal DA levels. PD-related akinesia and cataleptic behavior were attenuated by α-viniferin due to increase in striatal DA. Our study implies that α-viniferin can be used as an adjunct phytotherapeutic agent for mitigating PD-related behavioral deterioration.

Activation of Ca2+ phosphatase Calcineurin regulates Parkin translocation to mitochondria and mitophagy in flies.

Selective removal of dysfunctional mitochondria via autophagy is crucial for the maintenance of cellular homeostasis. This event is initiated by the translocation of the E3 ubiquitin ligase Parkin to damaged mitochondria, and it requires the Serine/Threonine-protein kinase PINK1. In a coordinated set of events, PINK1 operates upstream of Parkin in a linear pathway that leads to the phosphorylation of Parkin, Ubiquitin, and Parkin mitochondrial substrates, to promote ubiquitination of outer mitochondrial membrane proteins. Ubiquitin-decorated mitochondria are selectively recruiting autophagy receptors, which are required to terminate the organelle via autophagy. In this work, we show a previously uncharacterized molecular pathway that correlates the activation of the Ca2+-dependent phosphatase Calcineurin to Parkin translocation and Parkin-dependent mitophagy. Calcineurin downregulation or genetic inhibition prevents Parkin translocation to CCCP-treated mitochondria and impairs stress-induced mitophagy, whereas Calcineurin activation promotes Parkin mitochondrial recruitment and basal mitophagy. Calcineurin interacts with Parkin, and promotes Parkin translocation in the absence of PINK1, but requires PINK1 expression to execute mitophagy in MEF cells. Genetic activation of Calcineurin in vivo boosts basal mitophagy in neurons and corrects locomotor dysfunction and mitochondrial respiratory defects of a Drosophila model of impaired mitochondrial functions. Our study identifies Calcineurin as a novel key player in the regulation of Parkin translocation and mitophagy.

Melatonin synergizes with low doses of L-DOPA to improve dendritic spine density in the mouse striatum in experimental Parkinsonism.

The dopamine precursor, L-3,4-dihydroxyphenylalanine (L-DOPA), is the preferred drug for Parkinson's disease, but long-term treatment results in the drug-induced dyskinesias and other side effects. This study was undertaken to examine whether melatonin could potentiate low dose L-DOPA effects in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced experimental parkinsonism. Mice were treated with the parkinsonian neurotoxin, MPTP, and different doses of melatonin and low doses of L-DOPA. Behavior, striatal histology, and dopamine metabolism were evaluated on the 7th day. MPTP-induced striatal dopamine loss was not modified by melatonin administration (10-30 mg/kg; i.p. at 10-hr intervals, 6 times; or at 2-hr intervals, by day). However, low doses of L-DOPA (5 mg/kg, by oral gavage) administered alone or along with melatonin (10 mg/kg, i.p.) twice everyday for 2 days, 10 hr apart, after two doses of MPTP significantly attenuated striatal dopamine loss and provided improvements in both catalepsy and akinesia. Additionally, Golgi-impregnated striatal sections showed preservation of the medium spiny neurons, which have been damaged in MPTP-treated mouse. The results demonstrated that melatonin, but not L-DOPA, restored spine density and spine morphology of medium spiny neurons in the striatum and suggest that melatonin could be an ideal adjuvant to L-DOPA therapy in Parkinson's disease, and by the use of this neurohormone, it is possible to bring down the therapeutic doses of L-DOPA.

Corrigendum: USP14 as a therapeutic target against neurodegeneration: a rat brain perspective.

[This corrects the article DOI: 10.3389/fcell.2020.00727.].

Calcineurin inhibition protects against dopamine toxicity and attenuates behavioral decline in a Parkinson's disease model.

BACKGROUND: Parkinson's disease (PD), a highly prevalent neuro-motor disorder is caused due to progressive loss of dopaminergic (DAergic) neurons at substantia nigra region of brain. This leads to depleted dopamine (DA) content at striatum, thus affecting the fine tuning of basal ganglia. In patients, this imbalance is manifested by akinesia, catalepsy and tremor. PD associated behavioral dysfunctions are frequently mitigated by l-DOPA (LD) therapy, a precursor for DA synthesis. Due to progressive neurodegeneration, LD eventually loses applicability in PD. Although DA is cytotoxic, it is unclear whether LD therapy can accelerate PD progression or not. LD itself does not lead to neurodegeneration in vivo, but previous reports demonstrate that LD treatment mediated excess DA can potentiate neurotoxicity when PD associated genetic or epigenetic aberrations are involved. So, minimizing DA toxicity during the therapy is an absolute necessity to halt or slowdown PD progression. The two major contributing factors associated with DA toxicity are: degradation by Monoamine oxidase and DAquinone (DAQ) formation. RESULTS: Here, we report that apoptotic mitochondrial fragmentation via Calcineurin (CaN)-DRP1 axis is a common downstream event for both these initial cues, inhibiting which can protect cells from DA toxicity comprehensively. No protective effect is observed, in terms of cell survival when only PxIxIT domain of CaN is obstructed, demonstrating the importance to block DRP1-CaN axis specifically. Further, evaluation of the impact of DA exposure on PD progression in a mice model reveal that LD mediated behavioral recovery diminishes with time, mostly because of continued DAergic cell death and dendritic spine loss at striatum. CaN inhibition, alone or in combination with LD, offer long term behavioral protection. This protective effect is mediated specifically by hindering CaN-DRP1 axis, whereas inhibiting interaction between CaN and other substrates, including proteins involved in neuro-inflammation, remained ineffective when LD is co-administered. CONCLUSIONS: In this study, we conclude that DA toxicity can be circumvented by CaN inhibition and it can mitigate PD related behavioral aberrations by protecting neuronal architecture at striatum. We propose that CaN inhibitors might extend the therapeutic efficacy of LD treatment.

Myricitrin - a flavonoid isolated from the Indian olive tree (Elaeocarpus floribundus) - inhibits Monoamine oxidase in the brain and elevates striatal dopamine levels: therapeutic implications against Parkinson's disease.

Flavonoids exhibit several biological activities including inhibition of Monoamine oxidase (MAO), an enzyme that metabolizes several neurotransmitters. Thus, MAO inhibitors are well included in traditional therapeutic practices to fine-tune neuromotor behavior. This study aims to isolate flavonoids from a less explored plant of northeast India, named Indian olive (Elaeocarpus floribundus; Ef, family Elaeocarpaceae), and evaluate their MAO inhibitory properties. Four flavonoids from Ef leaf extract, namely, myricitrin, mearnsitrin, myricetin, and mearnsetin, are taken into consideration. Spectrofluorimetric assay is carried out to determine the MAO inhibitory properties. Next, in vitro and in vivo toxicity studies are performed in neuronal cell line and Drosophila, respectively. Furthermore, MAO inhibition by the selected compounds and their effect on dopamine levels are examined in the mouse brain. We evaluated the therapeutic potential in a mouse model of Parkinson's disease (PD) in terms of behavior, neurotransmitter levels, and dopaminergic neuronal loss. In an in vitro setup, all four compounds inhibited total MAO, whereas myricitrin exhibited some selectivity against MAO-B at 100 µM. Myricitrin and mearnsitrin exhibited no toxicity, in vitro or in vivo. However, only myricitrin inhibited MAO in the mouse brain and elevated dopamine levels. Myricitrin was able to attenuate motor incoordination in the mouse model of PD and improved dopamine levels in the striatum.

Colorectal cancer in younger adults from a Bi-National Colorectal Cancer Audit registry.

BACKGROUND: The incidence of colorectal cancer (CRC) in younger adults (<50 years old) is rising worldwide, at a rate of 1% per annum since mid-1980s. The clinical concern is that younger adults may have more advanced disease leading to poorer prognosis compared to their older cohort due to lack of screening. Therefore, the aim of this study is to assess the incidence and short-term outcomes of colorectal cancer in younger adults. METHODS: This is a retrospective study from a prospectively maintained bi-national database from 2007 to 2018. RESULTS: There were 1540 younger adults diagnosed with CRC, with a rise from 5.8% in 2007 to 8.4% in 2018. Majority had lower American Society of Anaesthesiologists (ASA) scores (89%), rectal cancers (46.1%) and higher tumour stage (65.4%). As a consequence, they were likely to have higher circumferential resection margin positivity (6%, P = 0.02) and to receive adjuvant chemotherapy (57.1%, P < 0.001) compared to their older cohort. Multivariate analysis showed disadvantaged socioeconomic status (odds ratio (OR) 3.3, 95% confidence interval (CI) 1.37-7.94, P < 0.001) and increasing tumour stage (OR 14.9, 95% CI 1.89-116.9, P < 0.001) were independent predictors for circumferential resection margin positivity whereas being female (OR 0.71, 95% CI 0.53-0.95, P = 0.02), higher ASA score (OR 175.3, 95% CI 26.7-1035.5, P < 0.001), urgent surgery (OR 2.75, 95% CI 1.84-4.11, P < 0.001) and anastomotic leak (OR 5.02, 95% CI 3.32-7.58, P < 0.001) were predictors of inpatient mortality. CONCLUSION: There is a steady rise in the incidence of colorectal cancer in younger adults. Both physicians and younger adults should be aware of the potential risk of colorectal cancer (CRC) and appropriate investigations performed so not to delay the diagnosis.

Deubiquitinating Enzymes in Parkinson's Disease.

Mitochondrial dysfunction and neurodegeneration have been directly correlated in many neurodegenerative disorders. Parkinson's disease (PD) in particular has been extensively studied in this context because of its well-characterized association with mitophagy, a selective type of autophagy that degrades mitochondria. Mitophagy is triggered by ubiquitin modification of proteins residing on the surface of mitochondria. Therefore, mitophagy is subject to suppression by deubiquitination. In recent years, many deubiquitinase enzymes (DUBs) emerged as therapeutic targets to compensate hindered mitophagy in PD. It is reasonable that inhibition of specific DUBs should induce mitophagy by blocking deubiquitination of mitochondrial proteins, although the signaling pathway is not always that linear. The broad aspect suggests that there could be cross talks among DUBs, which may in turn have synergistic effect to rescue the disease progression. In this short review we have highlighted DUBs that hold therapeutic value in the field of neurodegenerative diseases, PD in particular.

USP14 as a Therapeutic Target Against Neurodegeneration: A Rat Brain Perspective.

In the recent past, many of the deubiquitinases (DUB) were found to modulate mitochondrial clearance or mitophagy and thus they are currently projected as therapeutic targets against neurodegeneration. Among these DUBs, USP14 stands at a distinctive juncture, since it can influence both proteasome complex activity and autophagy process. USP14 interference can enhance mitochondrial clearance and thus can protect Parkinsonian phenotypes in Drosophila model. However, in higher animal models of neurodegenerative disorders, evaluation of the protective role of USP14 is yet to be done. In this perspective, we pointed out a few of the major considerations that should be classified before designing experiments to evaluate the therapeutic potential of this DUB in rodent models of neurodegeneration. These are mainly: level of USP14 in the concerned brain region and how the level alters in the model system. Because USP14 mediated mitophagy is Prohibitin2 dependent, the anticipated impact of this protein in this aspect is also discussed. To illustrate our view, we show that USP14 levels increases in adult rat brain substantia nigra (SN) and cerebellum compared to the young ones. We also depict that rotenone treatment can immediately lead to increased SN specific USP14 levels. Our perception thus portrays USP14 as a therapeutic target, especially for addressing SN specific neurodegeneration in adult rat brain, but may vary with the disease model.

Same-day angiography and embolization in delayed hematuria following percutaneous nephrolithotomy: an effective, safe, and time-saving approach.

PURPOSE: To evaluate the results of prompt, same-day selective angiography and transcatheter angioembolization (TAE) on delayed post-percutaneous nephrolithotomy (PCNL) hematuria. MATERIALS AND METHODS: Between 2011 and 2017, 21 patients with a mean age of 37 years (range, 21-60 years; males, 18) underwent digital subtraction angiography (DSA) and TAE to control delayed gross hematuria following PCNL. Discharged patients who following an uneventful PCNL presented to the emergency room with gross, brisk hematuria were included in the study and taken up for prompt, same-day DSA and same-session TAE with N-butyl-2-cyanoacrylate glue, without resorting to any initial conservative measures. All patient data were retrieved from medical records. RESULTS: Angiography revealed vascular lesions in all the cases (pseudoaneurysms, 14 cases; arteriovenous fistula, 2; mixed lesions, 5). The mean time of onset of delayed hemorrhage was 10.10±2.67 days. The average time from onset of bleeding to TAE was 4.31±0.64 hours (range 3.5-5.5 hours). Bleeding was controlled in all the cases without any recurrence or the need for further embolization. There were no procedural complications except for transient elevation of serum creatinine in four cases. CONCLUSION: Primary DSA and TAE is a safe, effective, and time-saving alternative to conservative management for post-PCNL, delayed, gross hematuria.

The reassuring CT scan with a lethal diagnosis.

We discuss an interesting case of a patient who presented with symptoms of abdominal and worsening chronic back pain with a known history of abdominal aortic aneurysm.

Safety of laparoscopic appendicectomy during pregnancy: a systematic review and meta-analysis.

BACKGROUND: Acute appendicitis is the most common non-obstetric surgical presentation during pregnancy. There were concerns that laparoscopic appendicectomy increases the risk of foetal loss compared to an open approach. Therefore, with recent advances in perioperative care, it is likely the risk has changed. Here, we performed an updated meta-analysis assessing the safety of laparoscopic appendicectomy in pregnant women. METHODS: A meta-analysis was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A search was undertaken between 2000 and 2017 on Ovid Medline and Embase. The primary outcome measures were foetal loss and preterm delivery, whereas secondary outcome measures were operative time and hospital length of stay. A random-effect model was performed to pool odds ratio (OR) and standardized mean difference (SMD). RESULTS: Seventeen observational studies were included, with 1886 patients in the laparoscopic and 4261 patients in the open group. Comparing laparoscopic versus open appendicectomy, there were 54 (5.96%) and 136 (3.73%) foetal losses, respectively. However, preterm delivery was much higher in the open approach (8.99%) compared to laparoscopic approach (2.84%). Pooled OR for foetal loss was 1.84 (95% confidence interval (CI) 1.31-2.58, P < 0.001), whereas OR for preterm delivery was 0.39 (95% CI 0.27-0.55, P < 0.001). There was no significant difference between both approaches for operative time (SMD -0.07; 95% CI -0.43 to 0.30, P = 0.71) or hospital length of stay (SMD -0.34; 95% CI -0.83 to 0.16, P = 0.18). CONCLUSION: In a pooled analysis of level III evidence, laparoscopic appendicectomy posed a higher risk of foetal loss but lower risk of preterm delivery. Caution and informed consent are crucial when offering a laparoscopic approach.

Inhibition of the deubiquitinase USP8 corrects a Drosophila PINK1 model of mitochondria dysfunction.

Aberrant mitochondrial dynamics disrupts mitochondrial function and contributes to disease conditions. A targeted RNA interference screen for deubiquitinating enzymes (DUBs) affecting protein levels of multifunctional mitochondrial fusion protein Mitofusin (MFN) identified USP8 prominently influencing MFN levels. Genetic and pharmacological inhibition of USP8 normalized the elevated MFN protein levels observed in PINK1 and Parkin-deficient models. This correlated with improved mitochondrial function, locomotor performance and life span, and prevented dopaminergic neurons loss in Drosophila PINK1 KO flies. We identified a novel target antagonizing pathologically elevated MFN levels, mitochondrial dysfunction, and dopaminergic neuron loss of a Drosophila model of mitochondrial dysfunction.