Bioorthogonal Chemical Reporters for Analyzing Protein Sulfenylation in Cells

Protein sulfenylation (RSOH), the redox‐based modification of cysteine thiol side chains by hydrogen peroxide (H2O2), is an important mechanism in signal transduction. Likewise, dysregulated protein sulfenylation contributes to a range of human pathologies, including cancer. Efforts to elucidate the diverse roles of protein sulfenylation in physiology and disease have been hampered by the lack of techniques to probe these modifications in native environments. To address this problem, selective chemical reporters have been developed for the detection and identification of sulfenylated proteins directly in cells. In the approach described here, a cyclic β‐diketone warhead is functionalized with an azide or alkyne chemical handle. An orthogonally functionalized biotin or fluorescent reporter is then appended to the probe post‐homogenization via click chemistry for downstream analysis. These bi‐functional probes are exquisitely selective for protein sulfenyl modifications, non‐toxic, and do not perturb intracellular redox balance. These reagents have been utilized to investigate sulfenylation in vitro and to identify intracellular protein targets of H2O2 during cell signaling. These methods provide a facile way to detect protein sulfenic acids and to study the biological role of cysteine oxidation with regard to physiological and pathological events. Curr. Protoc. Chem. Biol. 4:101‐122 © 2012 by John Wiley & Sons, Inc.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152599/1/cpch110219.pd

Probing the Role of Sulfenylation in Redox Regulation of Protein Kinases.

Hydrogen peroxide (H2O2) functions as a secondary messenger to regulate intracellular signaling cascades, largely through the modification of specific cysteine residues within redox-sensitive targets such as protein kinases. Oxidation can influence kinase activity in physiology and pathology, but the molecular mechanisms underlying these events remain largely unknown. In the present study, we present the development and application of chemical tools to detect and quantify changes in sulfenic acid formation (sulfenylation). These tools were used to demonstrate epidermal growth factor (EGF)-mediated signaling induces global and dynamic changes in protein sulfenylation. Three protein tyrosine phosphatases (PTPs) were shown to undergo EGF-dependent oxidation and exhibit a unique sulfenylation profile in cells, suggesting the extent of sulfenylation may be related to differences in subcellular locations of target proteins. In addition, epidermal growth factor receptor (EGFR) was identified as a direct target of signal-derived H2O2 at its active site cysteine (Cys797). Sulfenylation of EGFR Cys797 enhances its intrinsic tyrosine kinase activity, and subsequent work has demonstrated mutation of this residue abrogates EGFR autophosphorylation, sulfenylation, and decreases its affinity for ATP. These results highlight the importance of Cys797 with respect to EGFR function during normal cell signaling. Nine additional kinases harbor a cysteine residue that is structurally homologous to Cys797, and we present evidence that these kinases may be similarly regulated by oxidation of this residue. EGFR is mutated or amplified in a number of human carcinomas, and the proximity of Cys797 in the kinase domain potentially renders it more sensitive to oxidation in oncogenic mutants as shown by our data. Interestingly, EGFR Cys797 serves as a therapeutic target for covalent inhibitors that react with the reduced residue through electrophilic Michael addition. Oxidation of Cys797 alters the potency of current EGFR inhibitors that cannot recognize the kinase in its sulfenyl form. We report the development of a panel of first-generation nucleophilic RSOH-targeted inhibitors and evaluate compound potency towards EGFR Cys797 in response to concomitant oxidation. Collectively, the results of this thesis provide novel insight into how oxidative modification of kinases affects signal transduction pathways and have broad implications for therapeutics in disease states.PhDChemistryUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/107296/1/thuha_1.pd

A inovação aberta no processo de internacionalização de empresas: estudo de caso da Brasil Foods

TCC (graduação) - Universidade Federal de Santa Catarina. Centro Sócio-Econômico. Relações Internacionais.A presente monografia tem como objetivo o estudo do papel da inovação aberta no processo de internacionalização de empresas, a partir da revisão teórica dos conceitos na literatura e de um estudo de caso real de uma empresa brasileira de grande porte: a Brasil Foods. A presente pesquisa possui caráter de pesquisa exploratória. Para desenvolver o objetivo principal, o trabalho apresenta três objetivos específicos, que são: primeiro apresentar o conceito de inovação, seus graus de inserção e destacar a sua relevância no setor empresarial; segundo apresentar o conceito de inovação aberta e de inovação fechada e esclarecer a importância da difusão de informações; e, terceiro, apresentar os aspectos históricos da internacionalização de empresas, introduzindo duas teorias do processo: Modelo de Uppsala e Perspectiva de Networks. Assim, pode-se exibir, portanto, um modelo conceitual às relações entre as atividades de inovação aberta e a internacionalização de empresas em redes, levandose em consideração que a gestão de inovação nas empresas, atualmente, transcende a visão de inovação tecnológica, e, as redes internacionais ganham cada vez mais relevância como vantagem competitiva nas empresas ao atuar em mercados exteriores. Como resultado, concluiu-se que as estratégias de internacionalização de empresas em redes e as estratégias de inovação aberta, quando empregadas juntas, aumentam a velocidade de aprendizagem organizacional da Brasil Foods, acelerando os processos de internacionalização, confirmando que a inovação aberta estimula e intensifica a internacionalização de empresas que trabalham em redes

Analytical study of the sth-order perturbative corrections to the solution to a one-dimensional harmonic oscillator perturbed by a spatially power-law potential Vper(x) = λxα

In this work, we present a rigorous mathematical scheme for the derivation of the sth-order perturbative corrections to the solution to a one-dimensional harmonic oscillator perturbed by the potential V-per(x) = lambda x(alpha), where alpha is a positive integer, using the non-degenerate time-independent perturbation theory. To do so, we derive a generalized formula for the integral I = integral(+infinity)(-infinity)x(alpha)exp(-x(2))H-n(x)H-m(x)d(x), where H-n(x) denotes the Hermite polynomial of degree n, using the generating function of orthogonal polynomials. Finally, the analytical results with alpha = 3 and alpha = 4 are discussed in detail and compared with the numerical calculations obtained by the Lagrange-mesh method

Feasibility of wearable monitors to detect heart rate variability in children with hand, foot and mouth disease

Hand foot and mouth disease (HFMD) is caused by a variety of enteroviruses, and occurs in large outbreaks in which a small proportion of children deteriorate rapidly with cardiopulmonary failure. Determining which children are likely to deteriorate is difficult and health systems may become overloaded during outbreaks as many children require hospitalization for monitoring. Heart rate variability (HRV) may help distinguish those with more severe diseases but requires simple scalable methods to collect ECG data.We carried out a prospective observational study to examine the feasibility of using wearable devices to measure HRV in 142 children admitted with HFMD at a children's hospital in Vietnam. ECG data were collected in all children. HRV indices calculated were lower in those with enterovirus A71 associated HFMD compared to those with other viral pathogens.HRV analysis collected from wearable devices is feasible in a low and middle income country (LMIC) and may help classify disease severity in HFMD

Pneumonia: Drug-Related Problems and Hospital Readmissions

Pneumonia is one of the most common infectious diseases and the fourth leading cause of death globally. According to US statistics in 2019, pneumonia is the most common cause of sepsis and septic shock. In the US, inpatient pneumonia hospitalizations account for the top 10 highest medical costs, totaling $9.5 billion for 960,000 hospital stays. The emergence of antibiotic resistance in the treatment of infectious diseases, including the treatment of pneumonia, is a globally alarming problem. Antibiotic resistance increases the risk of death and re-hospitalization, prolongs hospital stays, and increases treatment costs, and is one of the greatest threats in modern medicine. Drug-related problems (DRPs) in pneumonia - such as suboptimal antibiotic indications, prolonged treatment duration, and drug interactions - increase the rate of antibiotic resistance and adverse effects, thereby leading to an increased burden in treatment. In a context in which novel and effective antibiotics are scarce, mitigating DRPs in order to reduce antibiotic resistance is currently a prime concern. A variety of interventions proven useful in reducing DRPs are antibiotic stewardship programs, the use of biomarkers, computerized physician order entries and clinical decision support systems, and community-acquired pneumonia scores

Randomised pharmacokinetic trial of rifabutin with lopinavir/ritonavir-antiretroviral therapy in patients with HIV-associated tuberculosis in Vietnam.

BACKGROUND: Rifampicin and protease inhibitors are difficult to use concomitantly in patients with HIV-associated tuberculosis because of drug-drug interactions. Rifabutin has been proposed as an alternative rifamycin, but there is concern that the current recommended dose is suboptimal. The principal aim of this study was to compare bioavailability of two doses of rifabutin (150 mg three times per week and 150 mg daily) in patients with HIV-associated tuberculosis who initiated lopinavir/ritonavir-based antiretroviral therapy in Vietnam. Concentrations of lopinavir/ritonavir were also measured. METHODS: This was a randomized, open-label, multi-dose, two-arm, cross-over trial, conducted in Vietnamese adults with HIV-associated tuberculosis in Ho Chi Minh City (Clinical trial registry number NCT00651066). Rifabutin pharmacokinetics were evaluated before and after the introduction of lopinavir/ritonavir -based antiretroviral therapy using patient randomization lists. Serial rifabutin and 25-O-desacetyl rifabutin concentrations were measured during a dose interval after 2 weeks of rifabutin 300 mg daily, after 3 weeks of rifabutin 150 mg daily with lopinavir/ritonavir and after 3 weeks of rifabutin 150 mg three times per week with lopinavir/ritonavir. RESULTS: Sixteen and seventeen patients were respectively randomized to the two arms, and pharmacokinetic analysis carried out in 12 and 13 respectively. Rifabutin 150 mg daily with lopinavir/ritonavir was associated with a 32% mean increase in rifabutin average steady state concentration compared with rifabutin 300 mg alone. In contrast, the rifabutin average steady state concentration decreased by 44% when rifabutin was given at 150 mg three times per week with lopinavir/ritonavir. With both dosing regimens, 2 - 5 fold increases of the 25-O-desacetyl- rifabutin metabolite were observed when rifabutin was given with lopinavir/ritonavir compared with rifabutin alone. The different doses of rifabutin had no significant effect on lopinavir/ritonavir plasma concentrations. CONCLUSIONS: Based on these findings, rifabutin 150 mg daily may be preferred when co-administered with lopinavir/ritonavir in patients with HIV-associated tuberculosis. TRIAL REGISTRATION: ClinicalTrials.gov NCT00651066

Spatiotemporal evolution of SARS-CoV-2 Alpha and Delta variants during large nationwide outbreak of COVID-19, Vietnam, 2021

We analyzed 1,303 SARS-CoV-2 whole-genome sequences from Vietnam, and found the Alpha and Delta variants were responsible for a large nationwide outbreak of COVID-19 in 2021. The Delta variant was confined to the AY.57 lineage and caused >1.7 million infections and >32,000 deaths. Viral transmission was strongly affected by nonpharmaceutical interventions

A Multicentre Molecular Analysis of Hepatitis B and Blood-Borne Virus Coinfections in Viet Nam

Hepatitis B (HBV) infection is endemic in Viet Nam, with up to 8.4 million individuals estimated to be chronically infected. We describe results of a large, multicentre seroepidemiological and molecular study of the prevalence of HBV infection and blood-borne viral coinfections in Viet Nam. Individuals with varying risk factors for infection (n = 8654) were recruited from five centres; Ha Noi, Hai Phong, Da Nang, Khanh Hoa and Can Tho. A mean prevalence rate of 10.7% was observed and levels of HBsAg were significantly higher in injecting drug users (IDUs) (17.4%, n = 174/1000) and dialysis patients (14.3%, n = 82/575) than in lower-risk groups (9.4%; p<0.001). Coinfection with HIV was seen in 28% of HBV-infected IDUs (n = 49/174) and 15.2% of commercial sex workers (CSWs; n = 15/99). HCV infection was present in 89.8% of the HBV-HIV coinfected IDUs (n = 44/49) and 40% of HBV-HIV coinfected CSWs (n = 16/40). Anti-HDV was detected in 10.7% (n = 34/318) of HBsAg positive individuals. Phylogenetic analysis of HBV S gene (n = 187) showed a predominance of genotype B4 (82.6%); genotypes C1 (14.6%), B2 (2.7%) and C5 (0.5%) were also identified. The precore mutation G1896A was identified in 35% of all specimens, and was more frequently observed in genotype B (41%) than genotype C (3%; p<0.0001). In the immunodominant ‘a’ region of the surface gene, point mutations were identified in 31% (n = 58/187) of sequences, and 2.2% (n = 4/187) and 5.3% (n = 10/187) specimens contained the major vaccine escape mutations G145A/R and P120L/Q/S/T, respectively. 368 HBsAg positive individuals were genotyped for the IL28B SNP rs12979860 and no significant association between the IL28B SNP and clearance of HBsAg, HBV viral load or HBeAg was observed. This study confirms the high prevalence of HBV infection in Viet Nam and also highlights the significant levels of blood-borne virus coinfections, which have important implications for hepatitis-related morbidity and development of effective management strategies