Effects of Bariatric Surgery on COVID-19: a Multicentric Study from a High Incidence Area

Introduction: The favorable effects of bariatric surgery (BS) on overall pulmonary function and obesity-related comorbidities could influence SARS-CoV-2 clinical expression. This has been investigated comparing COVID-19 incidence and clinical course between a cohort of patients submitted to BS and a cohort of candidates for BS during the spring outbreak in Italy. Materials and Methods: From April to August 2020, 594 patients from 6 major bariatric centers in Emilia-Romagna were administered an 87-item telephonic questionnaire. Demographics, COVID-19 incidence, suggestive symptoms, and clinical outcome parameters of operated patients and candidates to BS were compared. The incidence of symptomatic COVID-19 was assessed including the clinical definition of probable case, according to World Health Organization criteria. Results: Three hundred fifty-three operated patients (Op) and 169 candidates for BS (C) were finally included in the statistical analysis. While COVID-19 incidence confirmed by laboratory tests was similar in the two groups (5.7% vs 5.9%), lower incidence of most of COVID-19-related symptoms, such as anosmia (p: 0.046), dysgeusia (p: 0.049), fever with rapid onset (p: 0.046) were recorded among Op patients, resulting in a lower rate of probable cases (14.4% vs 23.7%; p: 0.009). Hospitalization was more frequent in C patients (2.4% vs 0.3%, p: 0.02). One death in each group was reported (0.3% vs 0.6%). Previous pneumonia and malignancies resulted to be associated with symptomatic COVID-19 at univariate and multivariate analysis. Conclusion: Patients submitted to BS seem to develop less severe SARS-CoV-2 infection than subjects suffering from obesity

Status of low-energy accelerator-based BNCT worldwide and in Argentina

Existing and active low-energy Accelerator-Based BNCT programs worldwide will be reviewed and compared. In particular, the program in Argentina will be discussed which consists of the development of an Electro-Static-Quadrupole (ESQ) Accelerator-Based treatment facility. The facility is conceived to operate with the deuteron-induced reactions 9Be(d,n)10B and 13C(d,n)14N at 1.45 MeV deuteron energy, as neutron sources. Neutron production target development status is specified. The present status of the construction of the new accelerator development laboratory and future BNCT centre is shown.Fil: Cartelli, Daniel Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; ArgentinaFil: Capoulat, Maria Eugenia. Comisión Nacional de Energía Atómica; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Baldo, M.. Comisión Nacional de Energía Atómica; ArgentinaFil: Suárez Sandín, J. C.. Comisión Nacional de Energía Atómica; ArgentinaFil: Igarzabal, M.. Comisión Nacional de Energía Atómica; ArgentinaFil: del Grosso, Mariela Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica; ArgentinaFil: Valda, A. A.. Comisión Nacional de Energía Atómica; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; ArgentinaFil: Canepa, N.. Comisión Nacional de Energía Atómica; ArgentinaFil: Gun, M.. Comisión Nacional de Energía Atómica; ArgentinaFil: Minsky, Daniel Mauricio. Comisión Nacional de Energía Atómica; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Conti, G.. Comisión Nacional de Energía Atómica; ArgentinaFil: Erhardt, J.. Comisión Nacional de Energía Atómica; ArgentinaFil: Somacal, Héctor Rubén. Comisión Nacional de Energía Atómica; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; ArgentinaFil: Bertolo, A. A.. Comisión Nacional de Energía Atómica; ArgentinaFil: Bergueiro, J.. Comisión Nacional de Energía Atómica; ArgentinaFil: Gaviola, P. A.. Comisión Nacional de Energía Atómica; ArgentinaFil: Kreiner, Andres Juan. Comisión Nacional de Energía Atómica; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Nerve growth factor induces neurite outgrowth of PC12 cells by promoting Gβγ-microtubule interaction

Background: Assembly and disassembly of microtubules (MTs) is critical for neurite outgrowth and differentiation. Evidence suggests that nerve growth factor (NGF) induces neurite outgrowth from PC12 cells by activating the receptor tyrosine kinase, TrkA. G protein-coupled receptors (GPCRs) as well as heterotrimeric G proteins are also involved in regulating neurite outgrowth. However, the possible connection between these pathways and how they might ultimately converge to regulate the assembly and organization of MTs during neurite outgrowth is not well understood. Results: Here, we report that Gβγ, an important component of the GPCR pathway, is critical for NGF-induced neuronal differentiation of PC12 cells. We have found that NGF promoted the interaction of Gβγ with MTs and stimulated MT assembly. While Gβγ-sequestering peptide GRK2i inhibited neurite formation, disrupted MTs, and induced neurite damage, the Gβγ activator mSIRK stimulated neurite outgrowth, which indicates the involvement of Gβγ in this process. Because we have shown earlier that prenylation and subsequent methylation/demethylation of γ subunits are required for the Gβγ-MTs interaction in vitro, small-molecule inhibitors (L-28 and L-23) targeting prenylated methylated protein methyl esterase (PMPMEase) were tested in the current study. We found that these inhibitors disrupted Gβγ and ΜΤ organization and affected cellular morphology and neurite outgrowth. In further support of a role of Gβγ-MT interaction in neuronal differentiation, it was observed that overexpression of Gβγ in PC12 cells induced neurite outgrowth in the absence of added NGF. Moreover, overexpressed Gβγ exhibited a pattern of association with MTs similar to that observed in NGF-differentiated cells. Conclusions: Altogether, our results demonstrate that βγ subunit of heterotrimeric G proteins play a critical role in neurite outgrowth and differentiation by interacting with MTs and modulating MT rearrangement. Electronic supplementary material The online version of this article (doi:10.1186/s12868-014-0132-4) contains supplementary material, which is available to authorized users

Increasing microtubule acetylation rescues axonal transport and locomotor deficits caused by LRRK2 Roc-COR domain mutations

​Leucine-rich repeat kinase 2 (​LRRK2) mutations are the most common genetic cause of Parkinson’s disease. ​LRRK2 is a multifunctional protein affecting many cellular processes and has been described to bind microtubules. Defective microtubule-based axonal transport is hypothesized to contribute to Parkinson’s disease, but whether ​LRRK2 mutations affect this process to mediate pathogenesis is not known. Here we find that ​LRRK2 containing pathogenic Roc-COR domain mutations (R1441C, Y1699C) preferentially associates with deacetylated microtubules, and inhibits axonal transport in primary neurons and in Drosophila, causing locomotor deficits in vivo. In vitro, increasing microtubule acetylation using deacetylase inhibitors or the tubulin acetylase ​αTAT1 prevents association of mutant ​LRRK2 with microtubules, and the deacetylase inhibitor ​trichostatin A (​TSA) restores axonal transport. In vivo knockdown of the deacetylases ​HDAC6 and ​Sirt2, or administration of ​TSA rescues both axonal transport and locomotor behavior. Thus, this study reveals a pathogenic mechanism and a potential intervention for Parkinson’s disease

Newly Developed Mg2+–Selective Fluorescent Probe Enables Visualization of Mg2+ Dynamics in Mitochondria

Mg2+ plays important roles in numerous cellular functions. Mitochondria take part in intracellular Mg2+ regulation and the Mg2+ concentration in mitochondria affects the synthesis of ATP. However, there are few methods to observe Mg2+ in mitochondria in intact cells. Here, we have developed a novel Mg2+–selective fluorescent probe, KMG-301, that is functional in mitochondria. This probe changes its fluorescence properties solely depending on the Mg2+ concentration in mitochondria under physiologically normal conditions. Simultaneous measurements using this probe together with a probe for cytosolic Mg2+, KMG-104, enabled us to compare the dynamics of Mg2+ in the cytosol and in mitochondria. With this method, carbonyl cyanide p-(trifluoromethoxy) phenylhydrazone (FCCP)–induced Mg2+ mobilization from mitochondria to the cytosol was visualized. Although a FCCP–induced decrease in the Mg2+ concentration in mitochondria and an increase in the cytosol were observed both in differentiated PC12 cells and in hippocampal neurons, the time-courses of concentration changes varied with cell type. Moreover, the relationship between mitochondrial Mg2+ and Parkinson's disease was analyzed in a cellular model of Parkinson's disease by using the 1-methyl-4-phenylpyridinium ion (MPP+). A gradual decrease in the Mg2+ concentration in mitochondria was observed in response to MPP+ in differentiated PC12 cells. These results indicate that KMG-301 is useful for investigating Mg2+ dynamics in mitochondria. All animal procedures to obtain neurons from Wistar rats were approved by the ethical committee of Keio University (permit number is 09106-(1))

Alterations in Energy/Redox Metabolism Induced by Mitochondrial and Environmental Toxins: A Specific Role for Glucose-6-Phosphate-Dehydrogenase and the Pentose Phosphate Pathway in Paraquat Toxicity

Parkinson’s disease (PD) is a multifactorial disorder with a complex etiology including genetic risk factors, environmental exposures, and aging. While energy failure and oxidative stress have largely been associated with the loss of dopaminergic cells in PD and the toxicity induced by mitochondrial/environmental toxins, very little is known regarding the alterations in energy metabolism associated with mitochondrial dysfunction and their causative role in cell death progression. In this study, we investigated the alterations in the energy/redox-metabolome in dopaminergic cells exposed to environmental/mitochondrial toxins (paraquat, rotenone, 1-methyl-4-phenylpyridinium [MPP+], and 6-hydroxydopamine [6-OHDA]) in order to identify common and/or different mechanisms of toxicity. A combined metabolomics approach using nuclear magnetic resonance (NMR) and direct-infusion electrospray ionization mass spectrometry (DI-ESI-MS) was used to identify unique metabolic profile changes in response to these neurotoxins. Paraquat exposure induced the most profound alterations in the pentose phosphate pathway (PPP) metabolome. 13C-glucose flux analysis corroborated that PPP metabolites such as glucose-6-phosphate, fructose-6-phosphate, glucono-1,5-lactone, and erythrose-4-phosphate were increased by paraquat treatment, which was paralleled by inhibition of glycolysis and the TCA cycle. Proteomic analysis also found an increase in the expression of glucose-6-phosphate dehydrogenase (G6PD), which supplies reducing equivalents by regenerating nicotinamide adenine dinucleotide phosphate (NADPH) levels. Overexpression of G6PD selectively increased paraquat toxicity, while its inhibition with 6-aminonicotinamide inhibited paraquat-induced oxidative stress and cell death. These results suggest that paraquat “hijacks” the PPP to increase NADPH reducing equivalents and stimulate paraquat redox cycling, oxidative stress, and cell death. Our study clearly demonstrates that alterations in energy metabolism, which are specific for distinct mitochondiral/environmental toxins, are not bystanders to energy failure but also contribute significant to cell death progression

Nitric oxide stabilizes microtubules during neuronal differentiation

Nitric oxide (NO) is a signalling molecule in the nervous system playing a role in neurotransmitter release, synaptic plasticity, excitability, learning, differentiation and development. The signalling pathway triggered by NO in physiological processes involves the activation of soluble guanylate cyclase, S-nitrosylation and nitration of proteins. Focusing on neuronal differentiation and development, NO-induced axonal retraction is involved in the refinement of neuronal projections during brain development and modulated by a S-nitrosylation-dependent signal \u2013transduction pathway leading to the reconfiguration of axonal microtubules. On the other hand, NO donors have been reported to enhance neurite outgrowth suggesting the positive effects of NO on neuritogenesis. Our previous results showed that nitrated proteins accumulate during neuronal differentiation and the cytoskeleton becomes the main cellular fraction containing nitrated proteins, being alpha-tubulin and tau two of the main targets, and that nitration correlates with increased microtubule stability. Here we have addressed the question of the possible role played by protein tyrosine nitration and microtubules during neuronal differentiation and neuritogenesis. We modulated the level of intracellular NO by donors and investigated the effects on nitration of proteins, neuritogenesis, arrangement and dynamics of microtubules. Our results show that low-dose NO exposure inducing an increase in nitrated proteins stimulates neurite elongation, microtubule growth and stabilization as shown by indirect immunofluorescence and live cell imaging. On the contrary, high-dose NO exposure induces axonal retraction, causes the accumulation of nitrated proteins at growth cone and destabilizes microtubules. We suggest that protein nitration plays a dual role during neuronal differentiation and modulates NO signalling to the microtubular cytoskeleton

Protein tyrosine nitration: a beneficial or detrimental cue during neuronal differentiation?

Nitric oxide (NO) is well established as an intracellular and transcellular signalling molecule in the nervous system playing a role in neurotransmitter release, synaptic plasticity, excitability, learning, differentiation and development. The majority of NO actions under physiological conditions occur through the activation of soluble guanylate cyclase, leading to the intracellular increase of cGMP. However, NO can also produce cGMP-independent effects in living cells through protein modification including S-nitrosylation and tyrosine nitration. Focusing on neuronal differentiation and development, NO-induced axonal retraction is involved in the refinement of neuronal projections during brain development and modulated by an S-nitrosylation-dependent signal \u2013transduction pathway leading to the reconfiguration of axonal microtubules. On the other hand, NO donors have been reported to enhance neurite outgrowth suggesting a positive effects of NO on neuritogenesis. We have addressed the question of the possible role played by protein tyrosine nitration in the signalling pathway triggered by NO during neuronal differentiation and neuritogenesis. Our previous results showed that nitrated proteins accumulate during NGF-induced differentiation of PC12 cells, the cytoskeleton becomes the main cellular fraction containing nitrated proteins, and that nitration correlates with increased microtubule stability. Here we have modulated the level of intracellular NO by donors and investigated the effects on nitration of proteins, neuritogenesis, arrangement and dynamics of the microtubular cytoskeleton. Our results show that NO donor (Glyco-SNAP-2) significantly affects neuritogenesis in NGF-differentiating PC12 cells. Low-dose NO exposure inducing an increase in nitrated protein stimulates neurite elongation and causes microtubule stabilization as shown by indirect immunofluorescence and live cell imaging analyses. In conclusion, our results reveal a dual role of protein nitration during neuronal differentiation and neuritogenesis, with a beneficial or cytotoxic actions depending on the NO concentration, and suggest the involvement of this posttranslational modification in modulation of NO signalling to the cytoskeleton

Neuronal microtubule dynamics as a novel target for the parkinsonism producing neurotoxin MPTP

Dysfunction of microtubule system is emerging as a novel contributing factor in Parkinson\u2019s disease (PD). Although tubulin, the protein which makes up microtubules, has been described to be a component of Lewy bodies long time ago (Galloway et al., 1992), only recent evidence indicates that the interaction with and the subsequent dysfunction of the microtubule cytoskeleton could be common to toxins known to cause PD and to proteins mutated in PD. We reported earlier that MPP+, the toxic metabolite of MPTP, binds specifically to tubulin and affects microtubule dynamics by acting as a destabilising factor in vitro (Cappelletti et al., 2005). Our current work is focused on the study of the dynamic behaviour of the microtubular cytoskeleton in NGF-differentiated PC12 cells exposed to MPP+. Here we investigate: i) post-translational modifications occurring on tubulin and correlating with stability of microtubules, and ii) tubulin dynamics in live cells. By immunofluorescence and confocal microscopy analysis we found that MPP+ heavily affects microtubule organization and induces the loss of highly labile microtubules at the neuronal tips. By FRAP (fluorescence recovery after photobleaching) experiments of YFP-tubulin in live PC12 cells we examined tubulin dynamics and found that MPP+ induces a significant reduction of tubulin movement at the neuronal tip and along the axon. Since dynamics is crucial in microtubule biological functions, we hypothesise that the altered dynamic behaviour of microtubules caused by MPP+ could profoundly affect the functionality of neurones and, consequently, represent a novel pathogenetic pathway triggering neuronal cell death