Association of body mass index and bloodstream infections in patients on extracorporeal membrane oxygenation: a single-centre, retrospective, cohort study

BACKGROUND

Obesity is associated with poor clinical outcomes in critically ill patients. However, under some clinical conditions, obesity has protective effects. Bloodstream infections (BSI) are among the most common nosocomial infections associated with extracorporeal membrane oxygenation (ECMO). BSI during ECMO is associated with higher mortality rates and poorer clinical outcomes.

AIM

To analyse whether body mass index (BMI) is associated with BSI during ECMO or with in-hospital mortality.

METHODS

All adult patients who had received ECMO support for >48 h were included in the analysis. The analysis of total duration of ECMO support, in-hospital mortality and BSI was stratified by BMI category. The Cox proportional hazards model was used to compare the risk of BSI among BMI categories.

FINDINGS

In total, 473 patients were enrolled in the study. The average age was 56.5 years and 65.3% were men. The total duration of ECMO was approximately 11.8 days, with a mortality rate of 47.1%. The incidence rates of BSI and candidaemia were 20.5% and 5.5%, respectively. The underweight group required ECMO for respiratory support, whereas the overweight and obese groups required ECMO for cardiogenic support (P<0.0001). No significant difference in BSI rate was found (P=0.784). However, after adjusting for clinical factors, patients in Group 4 (BMI 25.0-<30.0 kg/m2) exhibited lower mortality compared with patients in Group 2 (normal BMI) (P=0.004).

CONCLUSION

BMI was not associated with risk of BSI, but patients with higher BMI showed lower in-hospital mortality associated with ECMO support.

Non-muscle MYH10/myosin IIB recruits ESCRT-III to participate in autophagosome closure to maintain neuronal homeostasis

Dysfunction of the endosomal sorting complex required for transport (ESCRT) has been linked to frontotemporal dementia (FTD) due in part to the accumulation of unsealed autophagosomes. However, the mechanisms of ESCRT-mediated membrane closure events on phagophores remain largely unknown. In this study, we found that partial knockdown of non-muscle MYH10/myosin IIB/zip rescues neurodegeneration in both Drosophila and human iPSC-derived cortical neurons expressing FTD-associated mutant CHMP2B, a subunit of ESCRT-III. We also found that MYH10 binds and recruits several autophagy receptor proteins during autophagosome formation induced by mutant CHMP2B or nutrient starvation. Moreover, MYH10 interacted with ESCRT-III to regulate phagophore closure by recruiting ESCRT-III to damaged mitochondria during PRKN/parkin-mediated mitophagy. Evidently, MYH10 is involved in the initiation of induced but not basal autophagy and also links ESCRT-III to mitophagosome sealing, revealing novel roles of MYH10 in the autophagy pathway and in ESCRT-related FTD pathogenesis.Abbreviations: ALS: amyotrophic lateral sclerosis; AP: autophagosome; Atg: autophagy-related; ESCRT: endosomal sorting complex required for transport; FTD: frontotemporal dementia.

Mitigating Effects of Tenebrio molitor Larvae Powder Administration in Mice with Dextran Sodium Sulfate (DSS)- Induced Colitis

BACKGROUND

Ulcerative colitis (UC) is an inflammatory bowel disease that affects people worldwide. The causes of UC are diverse, and symptoms include diarrhea, weight loss, anemia, rectal bleeding, and bloody stools. Tenebrio molitor larvae have recently gained attention as edible insects with various physiological and medical effects. Research on the anti-inflammatory effects of ingesting Tenebrio molitor larvae powder (TMLP) is being actively conducted. In this study, TMLP was administered to mice with dextran sodium sulfate (DSS)-induced colitis to investigate its effects in reducing colitis symptoms.

METHODS

Mice were initially given 3% DSS in water to induce colitis and then feed containing 0%, 2%, or 4% TMLP. Pathologic changes in colon tissues were assessed by histology, and neutrophil levels were measured by myeloperoxidase (MPO) assay. Levels of IL-1β, IL-6, and TNF-α were measured using real-time PCR and ELISA assays, and IκB and NF-kB protein levels were measured by western blotting.

RESULT

Disease Activity Index (DAI) scores and MPO activity were reduced in TMLP-treated mice, and colon length increased as much as normal mice. Pathologic changes in the colon tissues of DSS-induced mice were attenuated, and the expression of inflammatory cytokine genes IL-1β, IL-6, and TNF-α decreased. Concomitant decreases in the protein expression of IL-1β and IL-6 were confirmed using ELISA. Western blotting revealed that levels of phosphorylated forms of IκB and NF-κB also decreased.

CONCLUSION

These results show that feeding TMLP to DSS-induced mice inhibited the typical inflammatory pathway of colitis. Therefore, TMLP shows potential as a food additive that can help treat colitis.
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Comparing the efficacy of different methods of faecal microbiota transplantation via oral capsule, oesophagogastroduodenoscopy, colonoscopy, or gastric tube

BACKGROUND

The increasing prevalence of multidrug-resistant organism (MDRO) carriage poses major challenges to medicine as healthcare costs increase. Recently, faecal microbiota transplantation (FMT) has been discussed as a novel and effective method for decolonizing MDRO.

AIM

To compare the efficacy of different FMT methods to optimize the success rate of decolonization in patients with MDRO carriage.

METHODS

This prospective cohort study enrolled patients with MDRO carriages from 2018 to 2021. Patients underwent FMT via one of the following methods: oral capsule, oesophagogastroduodenoscopy (EGD), colonoscopy, or gastric tube.

FINDINGS

A total of 57 patients underwent FMT for MDRO decolonization. The colonoscopy group required the shortest time for decolonization, whereas the EGD group required the longest (24.9 vs 190.4 days, P = 0.022). The decolonization rate in the oral capsule group was comparable to that in the EGD group (84.6% vs 85.7%, P = 0.730). An important clinical factor associated with decolonization failure was antibiotic use after FMT (odds ratio = 6.810, P = 0.008). All four groups showed reduced proportions of MDRO species in microbiome analysis after FMT.

CONCLUSION

Compared to other conventional methods, the oral capsule is an effective FMT method for patients who can tolerate an oral diet. The discontinuation of antibiotics after FMT is a key factor in the success of decolonization.

Development of new tools to study membrane-anchored mammalian Atg8 proteins

ABBREVIATIONS

A:C autophagic membrane:cytosol; ALS amyotrophic lateral sclerosis; ATG4 autophagy related 4; Atg8 autophagy related 8; BafA1 bafilomycin A₁; BNIP3L/Nix BCL2 interacting protein 3 like; CALCOCO2/NDP52 calcium binding and coiled-coil domain 2; EBSS Earle's balanced salt solution; GABARAP GABA type A receptor-associated protein; GST glutathione S transferase; HKO hexa knockout; K_d dissociation constant; LIR LC3-interacting region; MAP1LC3/LC3 microtubule associated protein 1 light chain 3; NLS nuclear localization signal/sequence; PE phosphatidylethanolamine; SpHfl1 Schizosaccharomyces pombeorganic solute transmembrane transporter; SQSTM1/p62 SQSTM1/p62; TARDBP/TDP-43 TAR DNA binding protein; TKO triple knockout.

Regulation of Cellular Ribonucleoprotein Granules: From Assembly to Degradation via Post-translational Modification

Cells possess membraneless ribonucleoprotein (RNP) granules, including stress granules, processing bodies, Cajal bodies, or paraspeckles, that play physiological or pathological roles. RNP granules contain RNA and numerous RNA-binding proteins, transiently formed through the liquid–liquid phase separation. The assembly or disassembly of numerous RNP granules is strongly controlled to maintain their homeostasis and perform their cellular functions properly. Normal RNA granules are reversibly assembled, whereas abnormal RNP granules accumulate and associate with various neurodegenerative diseases. This review summarizes current studies on the physiological or pathological roles of post-translational modifications of various cellular RNP granules and discusses the therapeutic methods in curing diseases related to abnormal RNP granules by autophagy.

Development and validation of an automatic commissioning tool for the Monte Carlo dose engine in myQA iON

Independent dose verification with Monte Carlo (MC) simulations is an important feature of proton therapy quality assurance (QA). However, clinical integration of such tools often generates an additional and complex workload for medical physicists. The preparation of the necessary clinical inputs, such as the machine beam model, should therefore be automated. In this work, a methodology for automatic MC commissioning has been devised, validated, and developed into a MATLAB tool for the users of myQA iON, the recent QA platform of IBA Dosimetry. With this workflow, all necessary parameters can easily be tuned using dedicated optimization methods. For the geometrical beam parameters (phase space), the assumption of a single or double Gaussian is made. To model the energy spectrum, a Gaussian function is assumed and parameters are optimized using either MC simulations or a library of pre-computed Bragg peaks. For the absolute dose calibration, commissioning fields can be reproduced with the dose engine to retrieve the necessary parameters. We discuss in a first time the tool efficiency and show that one can optimize all parameters in less than 4 min per energy with excellent accuracy. We then validate a beam model obtained with the tool by simulating homogeneous spread-out Bragg peaks (SOBPs) and patient QA plans previously measured in water. An average range agreement of 0.29 ± 0.34 mm is achieved for the SOBPs while 3%/3 mm local gamma passing rates reach 99.3% on average over all 62 measured patient QA planes, which is well within clinical tolerances.

Gene therapy for cystic fibrosis: new tools for precision medicine

The discovery of the Cystic fibrosis (CF) gene in 1989 has paved the way for incredible progress in treating the disease such that the mean survival age of individuals living with CF is now ~58 years in Canada. Recent developments in gene targeting tools and new cell and animal models have re-ignited the search for a permanent genetic cure for all CF. In this review, we highlight some of the more recent gene therapy approaches as well as new models that will provide insight into personalized therapies for CF.

A Developmental Role of the Cystic Fibrosis Transmembrane Conductance Regulator in Cystic Fibrosis Lung Disease Pathogenesis

The cystic fibrosis (CF) transmembrane conductance regulator (CFTR) protein is a cAMP-activated anion channel that is critical for regulating fluid and ion transport across the epithelium. This process is disrupted in CF epithelia, and patients harbouring CF-causing mutations experience reduced lung function as a result, associated with the increased rate of mortality. Much progress has been made in CF research leading to treatments that improve CFTR function, including small molecule modulators. However, clinical outcomes are not necessarily mutation-specific as individuals harboring the same genetic mutation may present with varying disease manifestations and responses to therapy. This suggests that the CFTR protein may have alternative functions that remain under-appreciated and yet can impact disease. In this mini review, we highlight some notable research implicating an important role of CFTR protein during early lung development and how mutant CFTR proteins may impact CF airway disease pathogenesis. We also discuss recent novel cell and animal models that can now be used to identify a developmental cause of CF lung disease.

Deciphering the role of a membrane-targeting domain in assisting endosomal and autophagic membrane localization of a RavZ protein catalytic domain

The bacterial effector protein RavZ from a pathogen can impair autophagy in the host by delipidating the mammalian autophagy- related gene 8 (mATG8)-phosphatidylethanolamine (PE) on autophagic membranes. In RavZ, the membrane-targeting (MT) domain is an essential function. However, the molecular mechanism of this domain in regulating the intracellular localization of RavZ in cells is unclear. In this study, we found that the fusion of the green fluorescent protein (GFP) to the MT domain of RavZ (GFP-MT) resulted in localization primarily to the cytosol and nucleus, whereas the GFP-fused duplicated-MT domain (GFP-2xMT) localized to Rab5- or Rab7-positive endosomes. Similarly, GFP fusion to the catalytic domain (CA) of RavZ (GFP-CA) resulted in localization primarily to the cytosol and nucleus, even in autophagy-induced cells. However, by adding the MT domain to GFP-CA (GFP-CA-MT), the cooperation of MT and CA led to localization on the Rab5-positive endosomal membranes in a wortmannin-sensitive manner under nutrient-rich conditions, and to autophagic membranes in autophagy-induced cells. In autophagic membranes, GFP-CA-MT delipidated overexpressed or endogenous mATG8-PE. Furthermore, GFP-CAΔα3-MT, an α3 helix deletion within the CA domain, failed to localize to the endosomal or autophagic membranes and could not delipidate overexpressed mATG8-PE. Thus, the CA or MT domain alone is insufficient for stable membrane localization in cells, but the cooperation of MT and CA leads to localization to the endosomal and autophagic membranes. In autophagic membranes, the CA domain can delipidate mATG8-PE without requiring substrate recognition mediated by LC3-interacting region (LIR) motifs. [BMB Reports 2021; 54(2): 118-123].

Autophagy activity contributes to the impairment of social recognition in Epac2-/- mice

Autophagy is a lysosomal degradation pathway that regulates cellular homeostasis. It is constitutively active in neurons and controls the essential steps of neuronal development, leading to its dysfunction in neurodevelopmental disorders. Although mTOR-associated impaired autophagy has previously been reported in neurodevelopmental disorders, there is lack of information about the dysregulation of mTOR-independent autophagy in neurodevelopmental disorders. In this study, we investigated whether the loss of Epac2, involved in the mTOR-independent pathway, affects autophagy activity and whether the activity of autophagy is associated with social-behavioral phenotypes in mice with Epac2 deficiencies. We observed an accumulation of autophagosomes and a significant increase in autophagic flux in Epac2-deficient neurons, which had no effect on mTOR activity. Next, we examined whether an increase in autophagic activity contributed to the social behavior exhibited in Epac2^-/- mice. The social recognition deficit observed in Epac2^-/- mice recovered in double transgenic Epac2^-/-: Atg5^+/- mice. Our study suggests that excessive autophagy due to Epac2 deficiencies may contribute to social recognition defects through an mTOR-independent pathway.

Variations in the Course of the Carotid Arteries in Patients with Retropharyngeal Parathyroid Adenomas

The carotid arteries, classically described as taking a relatively straight course through the neck, deviate medially in a minority of patients. At the extreme, the internal carotid arteries may "kiss" in the midline, coming extremely close to the pharyngeal wall. In this clinical report, we describe 5 patients with primary hyperparathyroidism, all with ectopic retropharyngeal parathyroid adenomas but all with varying carotid artery anatomy. We describe these variations using a previously developed clinical grading system that highlights 1) the relationship between carotid artery location and risk of injury during pharyngeal procedures and 2) the importance of universal, objective criteria to classify carotid anatomy. Radiologists should be familiar with variations in carotid anatomy and communicate them to the operative team.

Development of robustness evaluation strategies for enabling statistically consistent reporting

Robustness evaluation of proton therapy treatment plans is essential for ensuring safe treatment delivery. However, available evaluation procedures feature a limited exploration of the actual robustness of the plan and generally do not provide confidence levels. This study compared established and more sophisticated robustness evaluation procedures, with quantified confidence levels. We have evaluated several robustness evaluation methods for 5 bilateral head-and-neck patients optimized considering spot scanning delivery and with a conventional CTV-to-PTV margin of 4 mm. Method (1) good practice scenario selection (GPSS) (e.g. +/- 4 mm setup error 3% range uncertainty); (2) statistically sound scenario selection (SSSS) either only on or both on and inside isoprobability hypersurface encompassing 90% of the possible errors; (3) statistically sound dosimetric selection (SSDS). In the last method, the 90% best plans were selected according to either target coverage quantified by D 95 (SSDS_D 95) or to an approximation of the final objective function (OF) used during treatment optimization (SSDS_OF). For all methods, we have considered systematic setup and systematic range errors. A mix of systematic and random setup errors were also simulated for SSDS, but keeping the same conventional margin of 4 mm. All robustness evaluations have been performed using the fast Monte Carlo dose engine MCsquare. Both SSSS strategies yielded on average very similar results. SSSS and GPSS yield comparable values for target coverage (within 0.5 Gy). The most noticeable differences were found for the CTV between GPSS, on the one hand, and SSDS_D 95 and SSDS_OF, on the other hand (average worst-case D 98 were 2.8 and 2.0 Gy larger than for GPSS, respectively). Simulating explicitly random errors in SSDS improved almost all DVH metrics. We have observed that the width of DVH-bands and the confidence levels depend on the method chosen to sample the scenarios. Statistically sound estimation of the robustness of the plan in the dosimetric space may provide an improved insight on the actual robustness of the plan for a given confidence level.

p62/SQSTM1-droplet serves as a platform for autophagosome formation and anti-oxidative stress response

Autophagy contributes to the selective degradation of liquid droplets, including the P-Granule, Ape1-complex and p62/SQSTM1-body, although the molecular mechanisms and physiological relevance of selective degradation remain unclear. In this report, we describe the properties of endogenous p62-bodies, the effect of autophagosome biogenesis on these bodies, and the in vivo significance of their turnover. p62-bodies are low-liquidity gels containing ubiquitin and core autophagy-related proteins. Multiple autophagosomes form on the p62-gels, and the interaction of autophagosome-localizing Atg8-proteins with p62 directs autophagosome formation toward the p62-gel. Keap1 also reversibly translocates to the p62-gels in a p62-binding dependent fashion to activate the transcription factor Nrf2. Mice deficient for Atg8-interaction-dependent selective autophagy show that impaired turnover of p62-gels leads to Nrf2 hyperactivation in vivo. These results indicate that p62-gels are not simple substrates for autophagy but serve as platforms for both autophagosome formation and anti-oxidative stress.

Targeted epigenetic modulation using a DNA-based histone deacetylase inhibitor enhances cardiomyogenesis in mouse embryonic stem cells

The epigenome has an essential role in orchestrating transcriptional activation and modulating key developmental processes. Previously, we developed a library of pyrrole-imidazole polyamides (PIPs) conjugated with suberoylanilide hydroxamic acid (SAHA), a histone deacetylase (HDAC) inhibitor, for the purpose of sequence-specific modification of epigenetics. Based on the gene expression profile of SAHA-PIPs and screening studies using the α-myosin heavy chain promoter-driven reporter and SAHA-PIP library, we identified that SAHA-PIP G activates cardiac-related genes. Studies in mouse ES cells showed that SAHA-PIP G could enhance the generation of spontaneous beating cells, which is consistent with upregulation of several cardiac-related genes. Moreover, ChIP-seq results confirmed that the upregulation of cardiac-related genes is highly correlated with epigenetic activation, relevant to the sequence-specific binding of SAHA-PIP G. This proof-of-concept study demonstrating the applicability of SAHA-PIP not only improves our understanding of epigenetic alterations involved in cardiomyogenesis but also provides a novel chemical-based strategy for stem cell differentiation.

Cohen Syndrome Patient iPSC-Derived Neurospheres and Forebrain-Like Glutamatergic Neurons Reveal Reduced Proliferation of Neural Progenitor Cells and Altered Expression of Synapse Genes

Cohen syndrome (CS), a rare autosomal recessive disorder, has been associated with genetic mutations in the VPS13B gene, which regulates vesicle-mediated protein sorting and transport. However, the cellular mechanism underlying CS pathogenesis in patient-derived human neurons remains unknown. We identified a novel compound heterozygous mutation, due to homozygous variation of biparental origin and heterozygous variation inherited from the father, in the VPS13B gene in a 20-month-old female patient. To understand the cellular pathogenic mechanisms, we generated induced pluripotent stem cells (iPSCs) from the fibroblasts of the CS patient. The iPSCs were differentiated into forebrain-like functional glutamatergic neurons or neurospheres. Functional annotation from transcriptomic analysis using CS iPSC-derived neurons revealed that synapse-related functions were enriched among the upregulated and downregulated genes in the CS neurons, whereas processes associated with neurodevelopment were enriched in the downregulated genes. The developing CS neurospheres were small in size compared to control neurospheres, likely due to the reduced proliferation of SOX2-positive neural stem cells. Moreover, the number of SV2B-positive puncta and spine-like structures was significantly reduced in the CS neurons, suggesting synaptic dysfunction. Taking these findings together, for the first time, we report a potential cellular pathogenic mechanism which reveals the alteration of neurodevelopment-related genes and the dysregulation of synaptic function in the human induced neurons differentiated from iPSCs and neurospheres of a CS patient.

Autophagy pathway upregulation in a human iPSC-derived neuronal model of Cohen syndrome with VPS13B missense mutations

Significant clinical symptoms of Cohen syndrome (CS), a rare autosomal recessive disorder, include intellectual disability, facial dysmorphism, postnatal microcephaly, retinal dystrophy, and intermittent neutropenia. CS has been associated with mutations in the VPS13B (vacuolar protein sorting 13 homolog B) gene, which regulates vesicle-mediated protein sorting and transport; however, the cellular mechanism underlying CS pathogenesis in patient-derived neurons remains uncertain. This report states that autophagic vacuoles accumulate in CS fibroblasts and the axonal terminals of CS patient-specific induced pluripotent stem cells (CS iPSC)-derived neurons; additionally, autophagic flux was significantly increased in CS-derived neurons compared to control neurons. VPS13B knockout HeLa cell lines generated using the CRISPR/Cas9 genome editing system showed significant upregulation of autophagic flux, indicating that VSP13B may be associated with autophagy in CS. Transcriptomic analysis focusing on the autophagy pathway revealed that genes associated with autophagosome organization were dysregulated in CS-derived neurons. ATG4C is a mammalian ATG4 paralog and a crucial regulatory component of the autophagosome biogenesis/recycling pathway. ATG4C was significantly upregulated in CS-derived neurons, indicating that autophagy is upregulated in CS neurons. The autophagy pathway in CS neurons may be associated with the pathophysiology exhibited in the neural network of CS patients.

LIR motifs and the membrane-targeting domain are complementary in the function of RavZ

The bacterial effector protein RavZ is secreted by the intracellular pathogen Legionella pneumophila and inhibits host autophagy through an irreversible deconjugation of mammalian ATG8 (mATG8) proteins from autophagosome membranes. However, the roles of the LC3 interacting region (LIR) motifs in RavZ function remain unclear. In this study, we show that a membrane-targeting (MT) domain or the LIR motifs of RavZ play major or minor roles in RavZ function. A RavZ mutant that does not bind to mATG8 delipidated all forms of mATG8-phosphatidylethanolamine (PE) as efficiently as did wild-type RavZ. However, a RavZ mutant with a deletion of the MT domain selectively delipidated mATG8-PE less efficiently than did wild-type RavZ. Taken together, our results suggest that the effects of LIR motifs and the MT domain on RavZ activity are complementary and work through independent pathways.

Identification of a novel Shank2 transcriptional variant in Shank2 knockout mouse model of autism spectrum disorder

Autism spectrum disorder (ASD) is a group of neurodevelopmental disorders that are highly heterogeneous in clinical symptoms as well as etiologies. Mutations in SHANK2 are associated with ASD and accordingly, Shank2 knockout mouse shows ASD-like behavioral phenotypes, including social deficits. Intriguingly, two lines of Shank2 knockout (KO) mouse generated by deleting different exons (exon 6-7 or exon 7) showed distinct cellular phenotypes. Previously, we compared gene expressions between Shank2 KOs lacking exon 6-7 (e6-7 KO) and KOs lacking exon 7 (e7 KO) by performing RNA-seq. In this study, we expanded transcriptomic analyses to identify novel transcriptional variants in the KO mice. We found prominent expression of a novel exon (exon 4' or e4') between the existing exons 4 and 5 in the Shank2 e6-7 KO model. Expression of the transcriptional variant harboring this novel exon was confirmed by RT-PCR and western blotting. These findings suggest that the novel variant may function as a modifier gene, which contributes to the differences between the two Shank2 mutant lines. Furthermore, our result further represents an example of genetic compensation that may lead to phenotypic heterogeneity among ASD patients with mutations in the same gene.

Deciphering the molecular mechanisms underlying the plasma membrane targeting of PRMT8

Arginine methylation plays crucial roles in many cellular functions including signal transduction, RNA transcription, and regulation of gene expression. Protein arginine methyltransferase 8 (PRMT8), a unique brain-specific protein, is localized to the plasma membrane. However, the detailed molecular mechanisms underlying PRMT8 plasma membrane targeting remain unclear. Here, we demonstrate that the N-terminal 20 amino acids of PRMT8 are sufficient for plasma membrane localization and that oligomerization enhances membrane localization. The basic amino acids, combined with myristoylation within the N-terminal 20 amino acids of PRMT8, are critical for plasma membrane targeting. We also found that substituting Gly-2 with Ala [PRMT8(G2A)] or Cys-9 with Ser [PRMT8(C9S)] induces the formation of punctate structures in the cytosol or patch-like plasma membrane localization, respectively. Impairment of PRMT8 oligomerization/dimerization by Cterminal deletion induces PRMT8 mis-localization to the mitochondria, prevents the formation of punctate structures by PRMT8(G2A), and inhibits PRMT8(C9S) patch-like plasma membrane localization. Overall, these results suggest that oligomerization/dimerization plays several roles in inducing the efficient and specific plasma membrane localization of PRMT8. [BMB Reports 2019; 52(10): 601-606].

Cognition and cerebrovascular function in primary hyperparathyroidism before and after parathyroidectomy

PURPOSE

There are cognitive changes in primary hyperparathyroidism (PHPT) that improve with parathyroidectomy, but the mechanism of cognitive dysfunction has not been delineated. We assessed if cerebrovascular function is impaired in PHPT, improves post-parathyroidectomy and is associated with PTH level and cognitive dysfunction.

METHODS

This is an observational study of 43 patients with mild hypercalcemic or normocalcemic PHPT or goiter. At baseline, cerebrovascular function (dynamic cerebral autoregulation and vasomotor reactivity) by transcranial Doppler and neuropsychological function were compared between all three groups. A subset underwent parathyroidectomy or thyroidectomy, and was compared 6 months post-operatively.

RESULTS

Mean cerebrovascular and neuropsychological function was normal and no worse in PHPT compared to controls preoperatively. Higher PTH was associated with worse intracerebral autoregulation (r = - 0.43, p = 0.02) and worse cognitive performance on some tests. Post-parathyroidectomy, mood improved significantly, but changes did not differ compared to those having thyroidectomy (p = 0.84). There was no consistent improvement in cognition or change in vascular function in either surgical group.

CONCLUSIONS

Although higher PTH was associated with worse intracerebral autoregulation, cerebrovascular function, cognition and mood were normal in mild PHPT. PTX did not improve vascular or cognitive function. The observed improvement in mood cannot be clearly attributed to PTX. Notwithstanding the small sample size, the results do not support changing current criteria for parathyroidectomy to include cognitive complaints. However, the associations between PTH, cognition and cerebral autoregulation merit future studies in those with more severe hyperparathyroidism.

Monitoring LC3- or GABARAP-positive autophagic membranes using modified RavZ-based probes

Xenophagy is a selective lysosomal degradation pathway for invading pathogens in host cells. However, invading bacteria also develop survival mechanisms to inhibit host autophagy. RavZ is a protein secreted by Legionella that irreversibly delipidates mammalian autophagy-related protein 8 (mATG8) on autophagic membranes in host cells via efficient autophagic membrane targeting. In this study, we leveraged the autophagic membrane-targeting mechanism of RavZ and generated a new autophagosome probe by replacing the catalytic domain of RavZ with GFP. This probe is efficiently localized to mATG8-positive autophagic membranes via a synergistic combination between mATG8 protein-binding mediated by the LC3-interacting region (LIR) motifs and phosphoinositide-3-phosphate (PI3P) binding mediated by the membrane-targeting (MT) domain. Furthermore, the membrane association activity of this new probe with an MT domain was more efficient than that of probes with a hydrophobic domain that were previously used in LIR-based autophagosome sensors. Finally, by substituting the LIR motifs of RavZ with selective LIR motifs from Fyco1 or ULK2, we developed new probes for detecting LC3A/B- or GABARAP subfamily-positive autophagic membranes, respectively. We propose that these new RavZ-based sensors will be useful for monitoring and studying the function of mATG8-positive autophagic membranes in different cellular contexts for autophagy research.

P1756The protein APRIL predicts adverse outcomes in DAPT patients better than NT-proBNP and troponin

Aim

Dual antiplatelet therapy (DAPT) is a mainstay of post-ACS treatment. However, prediction of adverse events in these patients needs improving. We show here that the TNFα-related protein APRIL (which is produced in platelets and atherosclerotic plaque) is a superior predictor of MACE and new MI in DAPT recipients post-ACS.

Methods

We prospectively recruited 518 patients presenting with the primary complaint of acute chest pain to our hospital ED. Patients were adjudicated to have ACS by 2 independent cardiologists in accordance with ESC guidelines with hsTnI as biomarker. Plasma EDTA samples taken at presentation and 2 hours after were interrogated for APRIL measurements using a two site ELISA. Clinical data/variables, standard biochemistry analytes, hsTnT and NT-proBNP were also measured. Statistical assessments were made using SPSS v23 (IBM). Data for all biomarkers were treated as continuous variables and are presented as median (interquartile range, (IQR)). Statistical assessment of the comparative diagnostic abilities of APRIL, hsTnT, NT-proBNP and hsTnI were assessed using receiver operator curve (ROC) area under the curve (AUC) analysis. The comparative power of each biomarker (log values) to predict new MACE, MI, bleeding and mortality in 1) the whole group and in 2) DAPT recipients alone, within 2 yrs of index presentation was undertaken using a logistic regression base model (95% CI) that included all clinical variables and hsTnI and hsTnT, with APRIL and NT-proBNP each included in additional multivariate analyses.

Results

Of the 518 recruited patients (median age 63 (IQR: 54–73, 35% female), 152 were adjudicated to have ACS (29%, 115 MI, 37 UAP). Presentation APRIL levels were higher in those with a cardiac versus non-cardiac cause for presentation (3.0, (2.0–4.7) vs. 2.4, (1.6–3.8) ng/mL, P=0.001) and positively correlated with hsTnT and NT-proBNP (all P<0.001), but it did not add to the hsTnI (ROC = 0.96) or hsTnT (ROC =0.92) assisted diagnosis of ACS. In all 518 patients, in the multivariate regression model, APRIL was a significant independent predictor of mortality (n=54, P=0.032), new MI (n=43, P=0.006), new ADHF (n=24, P=0.016) and MACE (n=71, P=0.005) that was additive to NT-proBNP and troponin. In DAPT recipients alone (n=156), APRIL was the only biomarker to independently predict new MI (n=27, 95% CI: 1.125–3.982, P=0.020) and MACE (n=37, 95% CI: 1.058–3.389, P=0.031). None of the markers, only age, predicted bleeding episodes.

Conclusion

APRIL is an platelet/plaque derived marker that provides independent risk assessment in ACS patients. In DAPT recipients, the ability of APRIL to predict new MI and MACE is superior to that of cardiac troponins and NT-proBNP and could be used to identify high risk individuals.

Acknowledgement/Funding

Health Research Council of New Zealand; Heart Foundation of New Zealand

P3408The signal peptide of CNP is a novel predictor of MI, MACE and bleeding risk in chest pain patients

Aim

CNP is an important vascular and cardiac derived member of the natriuretic peptide family. We have previously provided the first reports that the signal peptide of CNP (CNPsp) is present in the human circulation and is elevated in those with chest pain suspicious of ACS. Here, show that CNPsp levels are highly predictive of new MI, MACE and post-index bleeding in patients presenting with potential ACS.

Methods

We prospectively recruited 493 patients presenting with the primary complaint of acute chest pain to our hospital ED. Patients were adjudicated as ACS by 2 independent cardiologists in accordance with ESC guidelines with hsTnI as biomarker. Plasma EDTA samples taken at presentation and 2 hours after were interrogated for CNPsp measurements using our validated, specific assay. Clinical data/variables, standard biochemistry analytes, hsTnT and NT-proBNP (both Roche Cobas e411) were also measured. Statistical assessments were made using SPSS v23. Data for all biomarkers were treated as continuous variables and are presented as median (interquartile range, (IQR)). Statistical assessment of the comparative abilities of CNPsp, hsTnT, NT-proBNP and hsTnI (log values) to predict new MACE, MI, bleeding and mortality within 2 yrs of index presentation was undertaken using a logistic regression base model (95% CI) that included all clinical variables and hsTnI and hsTnT and NT-proBNP, with CNPsp added to into the multivariate analyses.

Results

Of the 493 recruited patients (median age 63 (IQR: 54–73, 35% female), 148 were adjudicated to have ACS (30%, 109 MI, 39 UAP). Presentation CNPsp levels were not higher in those with adjudicated ACS versus non-ACS (51, (45–65) vs. 50, (42–63) pmol/L, P=0.412), did not correlate with hsTnI, hsTnT or NT-proBNP, but were significantly lower in those with a history of MI (49, (42–59) vs. 51, (43–64) pmol/L, P=0.044). In contrast, they were significantly higher in those with ECG ST-depression (56, (47–85) vs. 50 (42–62) pmol/L, P=0.038). In the multivariate regression model of all 493 patients, lower values of CNPsp were a significant multivariate predictor of new MI (n=37, 95% CI: 0.06–0.89, P=0.038), MACE (n=64, 95% CI: 0.08–0.81, P=0.020) and new bleeding (n=40, 95% CI: 0.05–0.63, P=0.005) within 2 years of presentation. This predictive ability was additive and independent from NT-proBNP and troponin.

Conclusion

This is the first report that CNPsp measurement provides meaningful and independent risk assessment of important outcomes in ACS patients. In particular, the fact that lower levels of CNPsp are predictive of negative MI, MACE and bleeding outcomes suggests that CNPsp may have an unappreciated protective role in the cardiovascular system.

Acknowledgement/Funding

Health Research Council of New Zealand; Heart Foundation of New Zealand

Spatial Learning and Motor Deficits in Vacuolar Protein Sorting-associated Protein 13b (Vps13b) Mutant Mouse

Vacuolar protein sorting-associated protein 13B (VPS13B), also known as COH1, is one of the VPS13 family members which is involved in transmembrane transport, Golgi integrity, and neuritogenesis. Mutations in the VPS13B gene are associated with Cohen syndrome and other cognitive disorders such as intellectual disabilities and autism spectrum disorder (ASD). However, the patho-physiology of VPS13B-associated cognitive deficits is unclear, in part, due to the lack of animal models. Here, we generated a Vps13b exon 2 deletion mutant mouse and analyzed the behavioral phenotypes. We found that Vps13b mutant mice showed reduced activity in open field test and significantly shorter latency to fall in the rotarod test, suggesting that the mutants have motor deficits. In addition, we found that Vps13b mutant mice showed deficits in spatial learning in the hidden platform version of the Morris water maze. The Vps13b mutant mice were normal in other behaviors such as anxiety-like behaviors, working memory and social behaviors. Our results suggest that Vps13b mutant mice may recapitulate key clinical symptoms in Cohen syndrome such as intellectual disability and hypotonia. Vps13b mutant mice may serve as a useful model to investigate the pathophysiology of VPS13B-associated disorders.

Enhancement of the stability of Mycobacterium tuberculosis recombinant antigen expressed in Escherichia coli using cell lysis additives

BACKGROUND

Mycobacteria tuberculosis (Mtb), the causative agent of tuberculosis, is a slow-growing bacterium. Expression in Escherichia coli is a widely used method for large-scale production of diagnostic antigenic recombinant proteins. Expression of Mtb antigen in E. coli offers a rapid and, inexpensive alternative to conventional protein synthesis from Mtb. The addition of stabilizing additives during cell lysis or storage of Mtb antigenic protein plays a vital role in enhancing antigen stability. In this study, we evaluated the effects of additives on the stability of Mtb antigens expressed in E. coli.

METHODS

Immunodominant Mtb antigens, i.e., CFP-10, Rv3872, TB7.7, and TB9.7, were cloned, and recombinant proteins overexpressed in E. coli were gradually degraded in a time-dependent manner by incubation at 37 °C. Various stabilizing additives during storage or cell lysis before protein purification were investigated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot analysis.

RESULTS

CFP-10 and Rv3872 were mainly expressed in soluble form. The degraded form of the expressed protein after incubation at 37 °C was easily observed after 1 week. Increased stability was observed in a solution containing glycine for recombinant CFP-10 and Rv3872. TB9.7 was stable in a solution containing trehalose or mannitol. TB7.7 was stable in a solution containing sucrose, glycine, or polyethylene glycol.

CONCLUSION

Recombinant Mtb antigen stabilization using chemical additives inhibited protein degradation, leading to increased antigen stability and purification efficiency.

Novel GFP-fused protein probes for detecting phosphatidylinositol-4-phosphate in the plasma membrane

Phosphatidylinositol-4-phosphate (PI4P) plays a crucial role in cellular functions, including protein trafficking, and is mainly located in the cytoplasmic surface of intracellular membranes, which include the trans-Golgi network (TGN) and the plasma membrane. However, many PI4P-binding domains of membrane-associated proteins are localized only to the TGN because of the requirement of a second binding protein such as ADP-ribosylation factor 1 (ARF1) in order to be stably localized to the specific membrane. In this study, we developed new probes that were capable of detecting PI4P at the plasma membrane using the known TGN-targeting PI4P-binding domains. The PI4P-specific binding pleckstrin homology (PH) domain of various proteins including CERT, OSBP, OSH1, and FAPP1 was combined with the N-terminal moderately hydrophobic domain of the short-form of Aplysia phosphodiesterase 4 (S(N30)), which aids in plasma membrane association but cannot alone facilitate this association. As a result, we found that the addition of S(N30) to the N-terminus of the GFP-fused PH domain of OSBP (S(N30)-GFP-OSBP-PH), OSH1 (S(N30)-GFP-OSH1-PH), or FAPP1 (S(N30)-GFP-FAPP1-PH) could induce plasma membrane localization, as well as retain TGN localization. The plasma membrane localization of S(N30)-GFP-FAPP1-PH is mediated by PI4P binding only, whereas those of S(N30)-GFP-OSBP-PH and S(N30)-GFP-OSH1-PH are mediated by either PI4P or PI(4,5)P₂ binding. Taken together, we developed new probes that detect PI4P at the plasma membrane using a combination of a moderately hydrophobic domain with the known TGN-targeting PI4P-specific binding PH domain.

Development of GABARAP family protein-sensitive LIR-based probes for neuronal autophagy

Autophagy allows for lysosomal cellular degradation of cytosolic components. In particular, neuronal autophagy is essential for cellular homeostasis and neuronal survival and is tightly regulated by several autophagy-related (ATG) proteins in post-mitotic neurons. Among these ATG proteins, the LC3/GABARAP proteins are known to regulate autophagosome biogenesis/maturation and cargo recognition. However, little is known about the role of GABARAP family proteins in neuronal autophagy despite their abundant expression in post-mitotic neurons. We have previously developed HyD (Hydrophobic Domain)-LIR (LC3-interacting region)-based autophagosome markers. In this study, to monitor GABARAP family proteins in autophagosomes of post-mitotic neurons, we improved the sensitivity of the probes for specifically detecting endogenous GABARAP family proteins by adding one more LIR motif to the LIR probes. We have tested the efficiency of two different LIRs, from ULK2 and Stbd1, in regard to their cellular localization to autophagosomes. HyD-2xLIR(ULK2)-GFP and HyD-2xLIR(Stbd1)-GFP demonstrated specific localization to GABARAP-positive autophagosomes relative to LC3B-positive autophagosomes in MEF/HeLa cells in an autophagy-dependent manner. Indeed, HyD-2xLIR(Stbd1)-GFP could efficiently detect GABARAP-positive autophagosomes in cultured cortical neurons. Our improved GABARAP-sensitive probes will contribute toward understanding the specific role of GABARAP family proteins in regard to neuronal autophagy.

Down-regulated TMED10 in Alzheimer disease induces autophagy via ATG4B activation

Several studies have shown that dysfunction of macroautophagy/autophagy is associated with many human diseases, including neurodegenerative disease and cancer. To explore the molecular mechanisms of autophagy, we performed a cell-based functional screening with SH-SY5Y cells stably expressing GFP-LC3, using an siRNA library and identified TMED10 (transmembrane p24 trafficking protein 10), previously known as the γ-secretase-modulating protein, as a novel regulator of autophagy. Further investigations revealed that depletion of TMED10 induced the activation of autophagy. Interestingly, protein-protein interaction assays showed that TMED10 directly binds to ATG4B (autophagy related gene 4B cysteine peptidase), and the interaction is diminished under autophagy activation conditions such as rapamycin treatment and serum deprivation. In addition, inhibition of TMED10 significantly enhanced the proteolytic activity of ATG4B for LC3 cleavage. Importantly, the expression of TMED10 in AD (Alzheimer disease) patients was considerably decreased, and downregulation of TMED10 increased amyloid-β (Aβ) production. Treatment with Aβ increased ATG4B proteolytic activity as well as dissociation of TMED10 and ATG4B. Taken together, our results suggest that the AD-associated protein TMED10 negatively regulates autophagy by inhibiting ATG4B activity.Abbreviations: Aβ: amyloid-β; AD: Alzheimer disease; ATG: autophagy related; BECN1: beclin 1; BiFC: bimolecular fluorescence complementation; CD: cytosolic domain; GFP: green fluorescent protein; GLUC: Gaussia luciferase; IP: immunoprecipitation; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; LD: luminal domain; PD: Parkinson disease; ROS: reactive oxygen species; siRNA: small interfering RNA; SNP: single-nucleotide polymorphisms; TD: transmembrane domain; TMED10: transmembrane p24 trafficking protein 10; VC: C terminus of Venus fluorescent protein; VN: N terminus of Venus fluorescent protein.

Early major complications after bariatric surgery in the USA, 2003-2014: a systematic review and meta-analysis

The effectiveness of bariatric surgery has been well-studied. However, complications after bariatric surgery have been understudied. This review assesses <30-d major complications associated with bariatric procedures, including anastomotic leak, myocardial infarction and pulmonary embolism. This review included 71 studies conducted in the USA between 2003 and 2014 and 107,874 patients undergoing either gastric bypass, adjustable gastric banding or sleeve gastrectomy, with mean age of 44 years and pre-surgery body mass index of 46.5 kg m^-2 . Less than 30-d anastomotic leak rate was 1.15%; myocardial infarction rate was 0.37%; pulmonary embolism rate was 1.17%. Among all patients, mortality rate following anastomotic leak, myocardial infarction and pulmonary embolism was 0.12%, 0.37% and 0.18%, respectively. Among surgical procedures, <30-d after surgery, sleeve gastrectomy (1.21% [95% confidence interval, 0.23-2.19%]) had higher anastomotic leak rate than gastric bypass (1.14% [95% confidence interval, 0.84-1.43%]); gastric bypass had higher rates of myocardial infarction and pulmonary embolism than adjustable gastric banding or sleeve gastrectomy. During the review, we found that the quality of complication reporting is lower than the reporting of other outcomes. In summary, <30-d rates of the three major complications after either one of the procedures range from 0% to 1.55%. Mortality following these complications ranges from 0% to 0.64%. Future studies reporting complications after bariatric surgery should improve their reporting quality.

Combined influence of CT random noise and HU-RSP calibration curve nonlinearities on proton range systematic errors

Proton range random and systematic uncertainties are the major factors undermining the advantages of proton therapy, namely, a sharp dose falloff and a better dose conformality for lower doses in normal tissues. The influence of CT artifacts such as beam hardening or scatter can easily be understood and estimated due to their large-scale effects on the CT image, like cupping and streaks. In comparison, the effects of weakly-correlated stochastic noise are more insidious and less attention is drawn on them partly due to the common belief that they only contribute to proton range uncertainties and not to systematic errors thanks to some averaging effects. A new source of systematic errors on the range and relative stopping powers (RSP) has been highlighted and proved not to be negligible compared to the 3.5% uncertainty reference value used for safety margin design. Hence, we demonstrate that the angular points in the HU-to-RSP calibration curve are an intrinsic source of proton range systematic error for typical levels of zero-mean stochastic CT noise. Systematic errors on RSP of up to 1% have been computed for these levels. We also show that the range uncertainty does not generally vary linearly with the noise standard deviation. We define a noise-dependent effective calibration curve that better describes, for a given material, the RSP value that is actually used. The statistics of the RSP and the range continuous slowing down approximation (CSDA) have been analytically derived for the general case of a calibration curve obtained by the stoichiometric calibration procedure. These models have been validated against actual CSDA simulations for homogeneous and heterogeneous synthetical objects as well as on actual patient CTs for prostate and head-and-neck treatment planning situations.

Development of LC3/GABARAP sensors containing a LIR and a hydrophobic domain to monitor autophagy

Macroautophagy allows for bulk degradation of cytosolic components in lysosomes. Overexpression of GFP/RFP-LC3/GABARAP is commonly used to monitor autophagosomes, a hallmark of autophagy, despite artifacts related to their overexpression. Here, we developed new sensors that detect endogenous LC3/GABARAP proteins at the autophagosome using an LC3-interacting region (LIR) and a short hydrophobic domain (HyD). Among HyD-LIR-GFP sensors harboring LIR motifs of 34 known LC3-binding proteins, HyD-LIR(TP)-GFP using the LIR motif from TP53INP2 allowed detection of all LC3/GABARAPs-positive autophagosomes. However, HyD-LIR(TP)-GFP preferentially localized to GABARAP/GABARAPL1-positive autophagosomes in a LIR-dependent manner. In contrast, HyD-LIR(Fy)-GFP using the LIR motif from FYCO1 specifically detected LC3A/B-positive autophagosomes. HyD-LIR(TP)-GFP and HyD-LIR(Fy)-GFP efficiently localized to autophagosomes in the presence of endogenous LC3/GABARAP levels and without affecting autophagic flux. Both sensors also efficiently localized to MitoTracker-positive damaged mitochondria upon mitophagy induction. HyD-LIR(TP)-GFP allowed live-imaging of dynamic autophagosomes upon autophagy induction. These novel autophagosome sensors can thus be widely used in autophagy research.

Sequestration of PRMT1 and Nd1-L mRNA into ALS-linked FUS mutant R521C-positive aggregates contributes to neurite degeneration upon oxidative stress

Mutations in fused in sarcoma (FUS), a DNA/RNA binding protein, are associated with familial amyotrophic lateral sclerosis (ALS). However, little is known about how ALS-causing mutations alter protein-protein and protein-RNA complexes and contribute to neurodegeneration. In this study, we identified protein arginine methyltransferase 1 (PRMT1) as a protein that more avidly associates with ALS-linked FUS-R521C than with FUS-WT (wild type) or FUS-P525L using co-immunoprecipitation and LC-MS analysis. Abnormal association between FUS-R521C and PRMT1 requires RNA, but not methyltransferase activity. PRMT1 was sequestered into cytosolic FUS-R521C-positive stress granule aggregates. Overexpression of PRMT1 rescued neurite degeneration caused by FUS-R521C upon oxidative stress, while loss of PRMT1 further accumulated FUS-positive aggregates and enhanced neurite degeneration. Furthermore, the mRNA of Nd1-L, an actin-stabilizing protein, was sequestered into the FUS-R521C/PRMT1 complex. Nd1-L overexpression rescued neurite shortening caused by FUS-R521C upon oxidative stress, while loss of Nd1-L further exacerbated neurite shortening. Altogether, these data suggest that the abnormal stable complex of FUS-R521C/PRMT1/Nd1-L mRNA could contribute to neurodegeneration upon oxidative stress. Overall, our study provides a novel pathogenic mechanism of the FUS mutation associated with abnormal protein-RNA complexes upon oxidative stress in ALS and provides insight into possible therapeutic targets for this pathology.

Role of the mammalian ATG8/LC3 family in autophagy: differential and compensatory roles in the spatiotemporal regulation of autophagy

Autophagy, an evolutionarily conserved cellular degradation pathway of the lysosome, is associated with many physiological and pathological processes. The hallmark of autophagy is the formation of the autophagosome that engulfs and degrades cytosolic components via its fusion with the lysosome, in either a selective or a non-selective manner. Autophagy is tightly regulated by proteins encoded by autophagy-related (atg) genes. Among these proteins, ATG8/LC3 is essential for autophagosome biogenesis/maturation and it also functions as an adaptor protein for selective autophagy. In mammalian cells, several homologs of yeast Atg8 such as MAP1LC3, GABARAP, and GABARAPL 1/2 have been identified. However, the biological relevance of this gene diversity in higher eukaryotes, and their specific roles, are largely unknown. In this review, we describe the mammalian ATG8/LC3 family and discuss recent advancements in understanding their roles in the autophagic process. [BMB Reports 2016; 49(8): 424-430]

Distinct regulations of ARF1 by two Aplysia Sec7 isoforms

Sec7 protein is a guanine nucleotide exchange factor in the ADP-ribosylation factor (ARF) family of small GTP-binding proteins. Aplysia Sec7 proteins (ApSec7s) play many roles in neurite outgrowth and synaptic facilitation in Aplysia neurons. However, the binding property of Aplysia ARF1 by ApSec7 isoforms has not been examined. In this study, we found that the cloned Aplysia ARF1 (ApARF1) protein only localized to the Golgi complex when it was expressed alone in HEK293T cells; however, if ApARF1 was co-expressed with plasma membrane-targeted ApSec7, it localized to both the plasma membrane and the Golgi complex via association with the Sec7 domain of ApSec7. Moreover, in HEK293T cells expressing both ApARF1 and another Sec7 isoform, ApSec7(VPKIS), the pleckstrin homology domain of ApSec7(VPKIS) associated with ApARF1, resulting in its localization to the Golgi complex. Overall, we propose a model in which ApSec7(VPKIS) activates ApARF1 in the Golgi complex, while ApSec7 recruits ApARF1 to the plasma membrane where it activates ApARF1/6 downstream signaling.

ApCPEB4, a non-prion domain containing homolog of ApCPEB, is involved in the initiation of long-term facilitation

Two pharmacologically distinct types of local protein synthesis are required for synapse- specific long-term synaptic facilitation (LTF) in Aplysia: one for initiation and the other for maintenance. ApCPEB, a rapamycin sensitive prion-like molecule regulates a form of local protein synthesis that is specifically required for the maintenance of the LTF. However, the molecular component of the local protein synthesis that is required for the initiation of LTF and that is sensitive to emetine is not known. Here, we identify a homolog of ApCPEB responsible for the initiation of LTF. ApCPEB4 which we have named after its mammalian CPEB4-like homolog lacks a prion-like domain, is responsive to 5-hydroxytryptamine, and is translated (but not transcribed) in an emetine-sensitive, rapamycin-insensitive, and PKA-dependent manner. The ApCPEB4 binds to different target RNAs than does ApCPEB. Knock-down of ApCPEB4 blocked the induction of LTF, whereas overexpression of ApCPEB4 reduces the threshold of the formation of LTF. Thus, our findings suggest that the two different forms of CPEBs play distinct roles in LTF; ApCPEB is required for maintenance of LTF, whereas the ApCPEB4, which lacks a prion-like domain, is required for the initiation of LTF.

Effect of concomitant vitamin D deficiency or insufficiency on lumbar spine volumetric bone mineral density and trabecular bone score in primary hyperparathyroidism

Lower vitamin D and higher parathyroid hormone (PTH) levels are associated with higher volumetric BMD and bone strength at the lumbar spine as measured by central quantitative computed tomography in primary hyperparathyroidism (PHPT), but there are no differences in bone microarchitecture as measured by trabecular bone score (TBS).

INTRODUCTION

The purpose of this study was to evaluate the association between 25-hydroxyvitamin D (25OHD) and volumetric bone mineral density (vBMD) and the TBS at the lumbar spine (LS) in PHPT.

METHODS

This is a cross-sectional analysis of PHPT patients with and without low 25OHD. We measured vBMD with quantitative computed tomography (cQCT) and TBS by dual-energy X-ray absorptiometry (DXA) at the LS in 52 and 88 participants, respectively.

RESULTS

In the cQCT cohort, those with lower vitamin D (<20 vs. 20-29 vs. ≥30 ng/ml) tended to be younger (p = 0.05), were less likely to use vitamin D supplementation (p < 0.01), and had better renal function (p = 0.03). Those with 25OHD <20 ng/ml had 80 and 126 % higher serum PTH levels respectively vs. those with 25OHD 20-29 ng/ml (p = 0.002) and 25OHD ≥30 ng/ml (p < 0.0001). Covariate-adjusted integral and trabecular vBMD were higher in those with 25OHD 20-29 vs. those with 25OHD ≥30 ng/ml, but those with 25OHD <20 did not differ. Because there were few participants with 25OHD deficiency, we also compared those with vitamin D <30 vs. ≥30 ng/ml. Covariate-adjusted integral and trabecular vBMD were 23 and 30 % higher respectively (both p < 0.05) in those with vitamin D <30 vs. ≥30 ng/ml. TBS was in the partially degraded range but did not differ by vitamin D status.

CONCLUSION

In mild PHPT, lower 25OHD is associated with higher PTH, but vitamin D deficiency and insufficiency using current clinical thresholds did not adversely affect lumbar spine skeletal health in PHPT. Further work is needed to determine if higher vBMD in those with lower vitamin D is due to an anabolic effect of PTH.

[Robust treatment planning in proton therapy]

The concentration of the dose delivered by protons at the end of their path, the Bragg peak, has the potential to improve external radiotherapy treatments. Unfortunately, the main strength of the protons, their finite range, is also their greatest weakness. Any uncertainty on the range may lead to inadequate target coverage or excessive toxicity. The uncertainties have multiple origins and include, among others, ballistic errors, morphological modifications or inaccurate estimations of the physical quantities necessary to predict the proton range. Uncertainties have been part of daily practice in conventional radiotherapy with X-rays for a long time. However, dose distributions delivered with X-rays are much less sensitive to uncertainties than the ones delivered with protons. This relative insensitivity enabled the management of uncertainties through safety margins using a simple formalism. The conditions of validity of this formalism are much more restrictive for proton therapy, leading to the need of developing new tools and adapted strategies to manage accurately these uncertainties. The objective of this paper is to present a vision for the management of uncertainties in proton therapy in the continuity of formalisms established for X-rays. The latter are first summarized before discussing the necessary developments in order to consistently apply them to protons.

Nasal delivery of chitosan-coated poly(lactide-co-glycolide)-encapsulated honeybee (Apis mellifera) venom promotes Th 1-specific systemic and local intestinal immune responses in weaned pigs

Nasal delivery is a convenient and acceptable route for drug administration, and has been shown to elicit a much more potent local and systemic response compared with other drug delivery routes. We previously demonstrated that rectal administration of poly(lactide-co-glycolide)-encapsulated honeybee venom (P-HBV) could enhance systemic Th 1-specific immune responses. We therefore synthesized chitosan-coated P-HBV (CP-HBV) and then evaluated the immune-boosting efficacy of nasally administered CP-HBV on systemic and local intestinal immunity compared with non-chitosan-coated P-HBV. The nasally delivered CP-HBV effectively enhanced Th 1-specific responses, eliciting a significant increase in the CD3(+)CD4(+)CD8(-) Th cell population, lymphocyte proliferation capacity, and expression of Th 1 cytokines (IFN-γ, IL-12, and IL-2) in peripheral blood mononuclear cells. Furthermore, these immune-boosting effects persisted up to 21days post CP-HBV administration. Nasal administration of CP-HBV also led to an increase of not only the CD4(+) Th 1 and IFN-γ secreting CD4(+) Th 1 cell population but also Th 1-specific cytokines and transcription factors, including IL-12, IFN-γ, STAT4, and T-bet, in isolated mononuclear cells from the spleen and ileum.

The roles of phosphoinositides in mammalian autophagy

Autophagy is an evolutionarily conserved cellular process for lysosomal degradation, which is involved in various physiological processes within cells. Its dysfunction is associated with many human diseases, such as cancer, liver diseases, heart diseases, and infectious diseases, including neurodegenerative diseases. Autophagy involves the formation of a double-membrane bound autophagosome and the degradation of cytosolic components via its fusion and maturation with the lysosome. One of the most important steps in the process of autophagy is membrane biogenesis during autophagosome formation/maturation from different membrane sources within cells. However, there is limited knowledge regarding: (1) how the core autophagy machinery is recruited to the initial site to initiate the formation of the isolation membrane and (2) how the autophagosome matures into the functional autolysosome. Lipid supply for nucleation/elongation of the autophagosome has been proposed as one possible mechanism. Accumulating evidence suggests the important role of phosphoinositides as phospholipids, which represent key membrane-localized signals in the regulation of fundamental cellular processes, in autophagosome formation and maturation. This review focuses on how phosphoinositides influence autophagy induction or autophagosome biogenesis/maturation, because the way they are altered by autophagy might contribute to the pathogenesis of human diseases.

Everolimus improves neuropsychiatric symptoms in a patient with tuberous sclerosis carrying a novel TSC2 mutation

Tuberous sclerosis complex (TSC) is a neurocutaneous disorder characterized by multiple symptoms including neuropsychological deficits such as seizures, intellectual disability, and autism. TSC is inherited in an autosomal dominant pattern and is caused by mutations in either the TSC1 or TSC2 genes, which enhance activation of the mammalian target of rapamycin (mTOR) signaling pathway. Recent studies have suggested that mTOR inhibitors such as rapamycin can reverse TSC-associated deficits in rodent models of TSC. In addition, clinical trials are ongoing to test the efficacy of mTOR inhibitors toward the psychiatric symptoms associated with TSC. Here, we report a case study of a Korean patient with TSC, who exhibited multiple symptoms including frequent seizures, intellectual disability, language delays, and social problems. We performed whole exome sequencing and identified a novel small deletion mutation in TSC2. Expressing the novel deletion mutant in HEK293T cells significantly increased mTOR pathway activation. Furthermore, everolimus treatment showed not only reduction in SEGA size, but dramatically improved behavioral deficits including autism related behaviors in the patient. In summary, we identified a novel small deletion mutation in TSC2 associated with severe TSC in a Korean family that enhances the activation of mTOR signaling in vitro. Everolimus treatment improved behavioral deficits in the patient.