Investigation of USP30 inhibition to enhance Parkin-mediated mitophagy: tools and approaches

Mitochondrial dysfunction is implicated in Parkinson disease (PD). Mutations in Parkin, an E3 ubiquitin ligase, can cause juvenile-onset Parkinsonism probably through impairment of mitophagy. Inhibition of the de-ubiquitinating enzyme USP30 may counter this effect to enhance mitophagy. Using different tools and cellular approaches, we wanted to independently confirm this claimed role for USP30. Pharmacological characterization of additional tool compounds that selectively inhibit USP30 are reported. The consequence of USP30 inhibition by these compounds, siRNA knockdown and overexpression of dominant-negative USP30 in the mitophagy pathway in different disease-relevant cellular models was explored. Knockdown and inhibition of USP30 showed increased p-Ser65-ubiquitin levels and mitophagy in neuronal cell models. Furthermore, patient-derived fibroblasts carrying pathogenic mutations in Parkin showed reduced p-Ser65-ubiquitin levels compared to wild-type cells, levels that could be restored using either USP30 inhibitor or dominant-negative USP30 expression. Our data provide additional support for USP30 inhibition as a regulator of the mitophagy pathway

Transcriptional co-activators YAP1-TAZ of Hippo signalling in doxorubicin-induced cardiomyopathy

Aims Hippo signalling is an evolutionarily conserved pathway that controls organ size by regulating apoptosis, cell proliferation, and stem cell self-renewal. Recently, the pathway has been shown to exert powerful growth regulatory activity in cardiomyocytes. However, the functional role of this stress-related and cell death-related pathway in the human heart and cardiomyocytes is not known. In this study, we investigated the role of the transcriptional co-activators of Hippo signalling, YAP and TAZ, in human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) in response to cardiotoxic agents and investigated the effects of modulating the pathway on cardiomyocyte function and survival. Methods and results RNA-sequencing analysis of human heart samples with doxorubicin-induced end-stage heart failure and healthy controls showed that YAP and ERBB2 (HER2) as upstream regulators of differentially expressed genes correlated with doxorubicin treatment. Thus, we tested the effects of doxorubicin on hiPSC-CMs in vitro. Using an automated high-content screen of 96 clinically relevant antineoplastic and cardiotherapeutic drugs, we showed that doxorubicin induced the highest activation of YAP/TAZ nuclear translocation in both hiPSC-CMs and control MCF7 breast cancer cells. The overexpression of YAP rescued doxorubicin-induced cell loss in hiPSC-CMs by inhibiting apoptosis and inducing proliferation. In contrast, silencing of YAP and TAZ by siRNAs resulted in elevated mitochondrial membrane potential loss in response to doxorubicin. hiPSC-CM calcium transients did not change in response to YAP/TAZ silencing. Conclusions Our results suggest that Hippo signalling is involved in clinical anthracycline-induced cardiomyopathy. Modelling with hiPSC-CMs in vitro showed similar responses to doxorubicin as adult cardiomyocytes and revealed a potential cardioprotective effect of YAP in doxorubicin-induced cardiotoxicity

Human ATG4 autophagy proteases counteract attachment of ubiquitin-like LC3/GABARAP proteins to other cellular proteins

Microtubule-associated protein 1 light chain 3 alpha (LC3)/GABA type A receptor–associated protein (GABARAP) comprises a family of ubiquitin-like proteins involved in (macro)autophagy, an important intracellular degradation pathway that delivers cytoplasmic material to lysosomes via double-membrane vesicles called autophagosomes. The only currently known cellular molecules covalently modified by LC3/GABARAP are membrane phospholipids such as phosphatidylethanolamine in the autophagosome membrane. Autophagy-related 4A cysteine peptidase (ATG4) proteases process inactive pro-LC3/GABARAP before lipidation, and the same proteases can also deconjugate LC3/GABARAP from lipids. To determine whether LC3/GABARAP has other molecular targets, here we generated a preprocessed LC3B mutant (Q116P) that is resistant to ATG4-mediated deconjugation. Upon expression in human cells and when assessed by immunoblotting under reducing and denaturing conditions, deconjugation-resistant LC3B accumulated in multiple forms and at much higher molecular weights than free LC3B. We observed a similar accumulation when preprocessed versions of all mammalian LC3/GABARAP isoforms were expressed in ATG4-deficient cell lines, suggesting that LC3/GABARAP can attach also to other larger molecules. We identified ATG3, the E2-like enzyme involved in LC3/GABARAP lipidation, as one target of conjugation with multiple copies of LC3/GABARAP. We show that LC3B–ATG3 conjugates are distinct from the LC3B–ATG3 thioester intermediate formed before lipidation, and we biochemically demonstrate that ATG4B can cleave LC3B–ATG3 conjugates. Finally, we determined ATG3 residue K243 as an LC3B modification site. Overall, we provide the first cellular evidence that mammalian LC3/GABARAP post-translationally modifies proteins akin to ubiquitination (‘LC3ylation’), with ATG4 proteases acting like deubiquitinating enzymes to counteract this modification (‘deLC3ylation’)

Angiotensin converting enzyme inhibitor therapy in children with Alport syndrome: effect on urinary albumin, TGF-β, and nitrite excretion

BACKGROUND: Angiotensin converting enzyme inhibitors are routinely prescribed to patients with chronic kidney disease because of their known renoprotective effects. We evaluated the effect of short-term therapy with the angiotensin converting enzyme inhibitor, enalapril, in early Alport syndrome, defined as disease duration less than 10 years and a normal glomerular filtration rate. METHODS: 11 children with early Alport syndrome were investigated. Two consecutive early morning urine specimens were collected at the start of the study for measurement of urinary creatinine, total protein, albumin, TGF-β, and nitrite excretion. Patients were treated with enalapril, ≅ 0.2 mg/kg/day, once a day for 14 days. Two early morning urine specimens were collected on days 13 and 14 of enalapril treatment and two weeks later for measurement of urinary creatinine, total protein, albumin, TGF-β, and nitrite excretion. RESULTS: Prior to treatment, urinary excretion of transforming growth factor-β and nitrite, the major metabolite of nitric oxide, was within normal limits in all patients. Administration of enalapril for 2 weeks did not alter urinary albumin, transforming growth factor-β, or nitrite excretion. CONCLUSION: These findings suggest that early Alport syndrome represents a disease involving exclusively intrinsic glomerular barrier dysfunction. At this stage of the illness, there is no evidence of angiotensin II-mediated proteinuria or increased production of transforming growth factor-β and, therefore, routine treatment with an angiotensin converting enzyme inhibitor may not be warranted

Philosophical aspects of personal branding in the context of informationculture and social nets (through the example of Instagram platform)

The article reveals the issue of the concept of personal branding in the context of information culture, social nets and social media. The relevance of the article is reasoned by the growing interest towardspersonal branding and people’s tendency to turn to commodity their personality, knowledge and experience in digital world. The general definitions of the process of commodification and personal branding aregiven. The due consideration is given to the manifestation of personal branding on the platform of Instagram. The author emphasizes the role of personal branding under the modern market conditions,created with the help of smart and digital technologies in the context of globalized world

A reversible phospho-switch mediated by ULK1 regulates the activity of autophagy protease ATG4B

Upon induction of autophagy, the ubiquitin-like protein LC3 is conjugated to phosphatidylethanolamine (PE) on the inner and outer membrane of autophagosomes to allow cargo selection and autophagosome formation. LC3 undergoes two processing steps, the proteolytic cleavage of pro-LC3 and the de-lipidation of LC3-PE from autophagosomes, both executed by the same cysteine protease ATG4. How ATG4 activity is regulated to co-ordinate these events is currently unknown. Here we find that ULK1, a protein kinase activated at the autophagosome formation site, phosphorylates human ATG4B on serine 316. Phosphorylation at this residue results in inhibition of its catalytic activity in vitro and in vivo. On the other hand, phosphatase PP2A-PP2R3B can remove this inhibitory phosphorylation. We propose that the opposing activities of ULK1-mediated phosphorylation and PP2A-mediated dephosphorylation provide a phospho-switch that regulates the cellular activity of ATG4B to control LC3 processing

Blueprint for a European calciphylaxis registry initiative: European Calciphylaxis Network (EuCalNet)

Calcific uraemic arteriolopathy (CUA) is a rare disease and continues to be a clinical challenge. The typical course of CUA is characterized by painful skin discolouration and induration evolving to necrotic ulcerations. Medial calcification of cutaneous arterioles and extensive extracellular matrix remodelling are the hallmarks of CUA. The epidemiology and risk factors associated with this disease are still not fully understood. Moreover, CUA treatment strategies vary significantly among centres and expert recommendations are heterogeneous. Registries may provide important insights and information to increase our knowledge about epidemiology and clinical aspects of CUA and may help to optimize its therapeutic management. In 2006, we established an internet-based registry in Germany (www.calciphylaxie.de) to allow online notification of patients with established or suspected CUA. The registry includes a comprehensive database with questions covering >70 parameters and items regarding patient-related and laboratory data, clinical background and presentation as well as therapeutic strategies. The next phase will be to allow international patient registration via www.calciphylaxis.net as part of the multinational EuCalNet (European Calciphylaxis Network) initiative, which is supported by the ERA-EDTA scientific working group \u2018CKD-MBD\u2019. Based on the valuable experience with the previous German CUA registry, EuCalNet will be a useful tool to collect data on the rare disease CUA and may become a basis for prospective controlled trials in the near future

Potent and broad neutralization of HIV-1 by a llama antibody elicited by immunization

Llamas (Lama glama) naturally produce heavy chain-only antibodies (Abs) in addition to conventional Abs. The variable regions (VHH) in these heavy chain-only Abs demonstrate comparable affinity and specificity for antigens to conventional immunoglobulins despite their much smaller size. To date, immunizations in humans and animal models have yielded only Abs with limited ability to neutralize HIV-1. In this study, a VHH phagemid library generated from a llama that was multiply immunized with recombinant trimeric HIV-1 envelope proteins (Envs) was screened directly for HIV-1 neutralization. One VHH, L8CJ3 (J3), neutralized 96 of 100 tested HIV-1 strains, encompassing subtypes A, B, C, D, BC, AE, AG, AC, ACD, CD, and G. J3 also potently neutralized chimeric simian-HIV strains with HIV subtypes B and C Env. The sequence of J3 is highly divergent from previous anti-HIV-1 VHH and its own germline sequence. J3 achieves broad and potent neutralization of HIV-1 via interaction with the CD4-binding site of HIV-1 Env. This study may represent a new benchmark for immunogens to be included in B cell-based vaccines and supports the development of VHH as anti-HIV-1 microbicides

Independent Component Analysis of the Effect of L-dopa on fMRI of Language Processing

L-dopa, which is a precursor for dopamine, acts to amplify strong signals, and dampen weak signals as suggested by previous studies. The effect of L-dopa has been demonstrated in language studies, suggesting restriction of the semantic network. In this study, we aimed to examine the effect of L-dopa on language processing with fMRI using Independent Component Analysis (ICA). Two types of language tasks (phonological and semantic categorization tasks) were tested under two drug conditions (placebo and L-dopa) in 16 healthy subjects. Probabilistic ICA (PICA), part of FSL, was implemented to generate Independent Components (IC) for each subject for the four conditions and the ICs were classified into task-relevant source groups by a correlation threshold criterion. Our key findings include: (i) The highly task-relevant brain regions including the Left Inferior Frontal Gyrus (LIFG), Left Fusiform Gyrus (LFUS), Left Parietal lobe (LPAR) and Superior Temporal Gyrus (STG) were activated with both L-dopa and placebo for both tasks, and (ii) as compared to placebo, L-dopa was associated with increased activity in posterior regions, including the superior temporal area (BA 22), and decreased activity in the thalamus (pulvinar) and inferior frontal gyrus (BA 11/47) for both tasks. These results raise the possibility that L-dopa may exert an indirect effect on posterior regions mediated by the thalamus (pulvinar)

Risk factors of one year increment of coronary calcifications and survival in hemodialysis patients

<p>Abstract</p> <p>Background</p> <p>Heart and coronary calcifications in hemodialysis patients are of very common occurrence and linked to cardiovascular events and mortality. Several studies have been published with similar results. Most of them were mainly cross-sectional and some of the prospective protocols were aimed to evaluate the results of the control of altered biochemical parameters of mineral disturbances with special regard to serum calcium, phosphate and CaxP with the use of calcium containing and calcium free phosphate chelating agents. The aim of the present study was to evaluate in hemodialysis patients classic and some non classic risk factors as predictors of calcification changes after one year and to evaluate the impact of progression on survival.</p> <p>Methods</p> <p>81 patients on hemodialysis were studied, with a wide age range and HD vintage. Several classic parameters and some less classic risk factors were studied like fetuin-A, CRP, 25-OHD and leptin. Calcifications, as Agatston scores, were evaluated with Multislice CT basally and after 12-18 months.</p> <p>Results</p> <p>Coronary artery calcifications were observed in 71 of 81 patients. Non parametric correlations between Agatston scores and Age, HD Age, PTH and CRP were significant. Delta increments of Agatston scores correlated also with serum calcium, CaxP, Fetuin-A, triglycerides and serum albumin. Logistic regression analysis showed Age, PTH and serum calcium as important predictors of Delta Agatston scores. LN transformation of the not normally distributed variables restricted the significant correlations to Age, BMI and CRP. Considering the Delta Agatston scores as dependent, significant predictors were Age, PTH and HDL. A strong association was found between basal calcification scores and Delta increment at one year. By logistic analysis, the one year increments in Agatston scores were found to be predictors of mortality. Diabetic and hypertensive patients have significantly higher Delta scores.</p> <p>Conclusions</p> <p>Progression of calcification is of common occurrence, with special regard to elevated basal scores, and is predictive of survival. Higher predictive value of survival is linked to the one year increment of calcification scores. Some classic and non classic risk factors play an important role in progression. Some of them could be controlled with appropriate management with possible improvement of mortality.</p