Canadian Lutheran World Relief and the Lutheran Immigration Board of Canada

Webinar 3 of the For the Sake of the Gospel Series was a participant-engagement webinar, whereas previous webinars were teaching sessions. Webinar participants consented to having their engagements recorded and used for educational purposes; some interactions from the public CHAT are included

Loss of respiratory complex I subunit NDUFB10 affects complex I assembly and supercomplex formation.

The orchestrated activity of the mitochondrial respiratory or electron transport chain (ETC) and ATP synthase convert reduction power (NADH, FADH2) into ATP, the cell's energy currency in a process named oxidative phosphorylation (OXPHOS). Three out of the four ETC complexes are found in supramolecular assemblies: complex I, III, and IV form the respiratory supercomplexes (SC). The plasticity model suggests that SC formation is a form of adaptation to changing conditions such as energy supply, redox state, and stress. Complex I, the NADH-dehydrogenase, is part of the largest supercomplex (CI + CIII2 + CIVn). Here, we demonstrate the role of NDUFB10, a subunit of the membrane arm of complex I, in complex I and supercomplex assembly on the one hand and bioenergetics function on the other. NDUFB10 knockout was correlated with a decrease of SCAF1, a supercomplex assembly factor, and a reduction of respiration and mitochondrial membrane potential. This likely is due to loss of proton pumping since the CI P P -module is downregulated and the P D -module is completely abolished in NDUFB10 knock outs.The study was supported by a grant from CRC944 (INST190/1672 and the z-project). Tasnim Arroum was supported by an HFSP doctoral fellowship (RGP0016/ 2018).S

The spatio-temporal organization of mitochondrial F1FO ATP synthase in cristae depends on its activity mode.

F1FO ATP synthase, also known as complex V, is a key enzyme of mitochondrial energy metabolism that can synthesize and hydrolyze ATP. It is not known whether the ATP synthase and ATPase function are correlated with a different spatio-temporal organisation of the enzyme. In order to analyze this, we tracked and localized single ATP synthase molecules in situ using live cell microscopy. Under normal conditions, complex V was mainly restricted to cristae indicated by orthogonal trajectories along the cristae membranes. In addition confined trajectories that are quasi immobile exist. By inhibiting glycolysis with 2-DG, the activity and mobility of complex V was altered. The distinct cristae-related orthogonal trajectories of complex V were obliterated. Moreover, a mobile subpopulation of complex V was found in the inner boundary membrane. The observed changes in the ratio of dimeric/monomeric complex V, respectively less mobile/more mobile complex V and its activity changes were reversible. In IF1-KO cells, in which ATP hydrolysis is not inhibited by IF1, complex V was more mobile, while inhibition of ATP hydrolysis by BMS-199264 reduced the mobility of complex V. Taken together, these data support the existence of different subpopulations of complex V, ATP synthase and ATP hydrolase, the latter with higher mobility and probably not prevailing at the cristae edges. Obviously, complex V reacts quickly and reversibly to metabolic conditions, not only by functional, but also by spatial and structural reorganization.This work was supported by the DFG (INST 190/167-2). K. Busch is associated with the CiM (Cells in Motion cluster, Munster).S

Lima1 mediates the pluripotency control of membrane dynamics and cellular metabolism.

Lima1 is an extensively studied prognostic marker of malignancy and is also considered to be a tumour suppressor, but its role in a developmental context of non-transformed cells is poorly understood. Here, we characterise the expression pattern and examined the function of Lima1 in mouse embryos and pluripotent stem cell lines. We identify that Lima1 expression is controlled by the naïve pluripotency circuit and is required for the suppression of membrane blebbing, as well as for proper mitochondrial energetics in embryonic stem cells. Moreover, forcing Lima1 expression enables primed mouse and human pluripotent stem cells to be incorporated into murine pre-implantation embryos. Thus, Lima1 is a key effector molecule that mediates the pluripotency control of membrane dynamics and cellular metabolism

Teste rápido para o HIV como estratégia de prevenção da transmissão vertical no Brasil

OBJECTIVE: To assess the feasibility of HIV rapid testing for pregnant women at maternity hospital admission and of subsequent interventions to reduce perinatal HIV transmission. METHODS: Study based on a convenience sample of women unaware of their HIV serostatus when they were admitted to delivery in public maternity hospitals in Rio de Janeiro and Porto Alegre, Brazil, between March 2000 and April 2002. Women were counseled and tested using the Determine HIV1/2 Rapid Test. HIV infection was confirmed using the Brazilian algorithm for HIV infection diagnosis. In utero transmission of HIV was determined using HIV-DNA-PCR. There were performed descriptive analyses of sociodemographic data, number of previous pregnancies and abortions, number of prenatal care visits, timing of HIV testing, HIV rapid test result, neonatal and mother-to-child transmission interventions, by city studied. RESULTS: HIV prevalence in women was 6.5% (N=1,439) in Porto Alegre and 1.3% (N=3.778) in Rio de Janeiro. In Porto Alegre most of women were tested during labor (88.7%), while in Rio de Janeiro most were tested in the postpartum (67.5%). One hundred and forty-four infants were born to 143 HIV-infected women. All newborns but one in each city received at least prophylaxis with oral zidovudine. It was possible to completely avoid newborn exposure to breast milk in 96.8% and 51.1% of the cases in Porto Alegre and Rio de Janeiro, respectively. Injectable intravenous zidovudine was administered during labor to 68.8% and 27.7% newborns in Porto Alegre and Rio de Janeiro, respectively. Among those from whom blood samples were collected within 48 hours of birth, in utero transmission of HIV was confirmed in 4 cases in Rio de Janeiro (4/47) and 6 cases in Porto Alegre (6/79). CONCLUSIONS: The strategy proved feasible in maternity hospitals in Rio de Janeiro and Porto Alegre. Efforts must be taken to maximize HIV testing during labor. There is a need of strong social support to provide this population access to health care services after hospital discharge.OBJETIVO: Analizar la viabilidad de evaluación rápida del HIV entre gestantes en la admisión en la maternidad y de intervenciones para reducir la transmisión perinatal del HIV. MÉTODOS: Muestra de conveniencia de mujeres que desconocían su situación serológica para el HIV al ser admitidas para el parto en maternidades públicas de Rio de Janeiro (Sureste) y de Porto alegre (Sur de Brasil), entre marzo de 2000 y abril de 2002. Las mujeres fueron aconsejadas y evaluadas con prueba rápida Determine HIV1/2 en la maternidad. Infección por el HIV fue confirmada por el algoritmo brasilero para el diagnóstico de la infección por el HIV. La transmisión intra- útero fue determinada por el PCR-DNA-HIV. Fueron realizados análisis descriptivos de los datos sociodemográficos, número de gestaciones y de abortos previos, número de visitas de prenatal, momento de la evaluación para el HIV, resultado de la prueba rápida para el HIV, intervenciones recibidas por los recién nacidos y de transmisión vertical del HIV, de acuerdo con cada ciudad. RESULTADOS: La prevalencia de HIV entre las mujeres fue de 6,5% (N=1.439) en Porto Alegre y 1,3% (N=3,778) en Rio de Janeiro. La mayoría fue evaluada durante el trabajo de parto en Porto Alegre y en el postparto, en Rio de Janeiro. Ciento y cuarenta y cuatro niños nacieron de 143 mujeres infectadas por el HIV. Todos los recién nacidos recibieron al menos la profilaxia con zidovudina oral, excepto uno en cada ciudad. Fue posible evitar cualquier exposición a la leche materna en 96,8% y 51,1% de los recién nacidos en Porto Alegre y en Rio de Janeiro, respectivamente. La zidovudina inyectable fue administrada durante el trabajo de parto a 68,8% de los recién nacidos en Porto Alegre y 27,7% en Rio de Janeiro. Entre aquellos con muestras de sangre colectadas hasta 48 horas de nacimiento, la transmisión intra-útero fue confirmada en cuatro casos en Rio de Janeiro (4/47) y en seis casos en Porto Alegre (6/79). CONCLUSIONES: La estrategia se mostró factible en las maternidades de Rio de Janeiro y de Porto Alegre. Esfuerzos deben ser emprendidos para maximizar la evaluación durante el trabajo de parto. Fuerte soporte social precisa ser acoplado a esa estrategia para garantizar el acceso de dicha población al sistema de salud posterior a ser dado de alta de la maternidad.OBJETIVO: Analisar a viabilidade da testagem rápida para o HIV entre gestantes na admissão à maternidade e de intervenções para reduzir a transmissão perinatal do HIV. MÉTODOS: Amostra de conveniência de mulheres que desconheciam sua situação sorológica para o HIV quando admitidas para o parto em maternidades públicas do Rio de Janeiro, RJ, e de Porto Alegre, RS, entre março de 2000 e abril de 2002. As mulheres foram aconselhadas e testadas com teste rápido Determine HIV1/2 na maternidade. Infecção pelo HIV foi confirmada pelo algoritmo brasileiro para o diagnóstico da infecção pelo HIV. A transmissão intra-útero foi determinada pelo PCR-DNA-HIV. Foram realizadas análises descritivas dos dados sociodemográficos, número de gestações e de abortos prévios, número de visitas de pré-natal, momento da testagem para o HIV, resultado do teste rápido para o HIV, intervenções recebidas pelos recém-natos e de transmissão vertical do HIV, de acordo com cada cidade. RESULTADOS: A prevalência de HIV entre as mulheres foi 6,5% (N=1.439) em Porto Alegre e 1,3% (N=3.778) no Rio de Janeiro. A maioria foi testada durante o trabalho de parto em Porto Alegre e no pós-parto, no Rio de Janeiro. Cento e quarenta e quatro crianças nasceram de 143 mulheres infectadas pelo HIV. Todos os recém-natos receberam ao menos a profilaxia com zidovudina oral, exceto um em cada cidade. Foi possível evitar qualquer exposição ao leite materno em 96,8% e 51,1% dos recém-natos em Porto Alegre e no Rio de Janeiro, respectivamente. A zidovudina injetável foi administrada durante o trabalho de parto para 68,8% dos recém-natos em Porto Alegre e 27,7% no Rio de Janeiro. Entre aqueles com amostras de sangue coletadas até 48 horas do nascimento, a transmissão intra-útero foi confirmada em quatro casos no Rio de Janeiro (4/47) e em seis casos em Porto Alegre (6/79). CONCLUSÕES: A estratégia mostrou-se factível nas maternidades do Rio de Janeiro e de Porto Alegre. Esforços devem ser empreendidos para maximizar a testagem durante o trabalho de parto. Forte suporte social precisa ser acoplado a essa estratégia para garantir o acesso dessa população ao sistema de saúde após a alta da maternidade

Teriflunomide treatment for multiple sclerosis modulates T cell mitochondrial respiration with affinity-dependent effects

International audienceInterference with immune cell proliferation represents a successful treatment strategy in T cell-mediated autoimmune diseases such as rheumatoid arthritis and multiple sclerosis (MS). One prominent example is pharmacological inhibition of dihydroorotate dehydrogenase (DHODH), which mediates de novo pyrimidine synthesis in actively proliferating T and B lymphocytes. Within the TERIDYNAMIC clinical study, we observed that the DHODH inhibitor teriflunomide caused selective changes in T cell subset composition and T cell receptor repertoire diversity in patients with relapsing-remitting MS (RRMS). In a preclinical antigen-specific setup, DHODH inhibition preferentially suppressed the proliferation of high-affinity T cells. Mechanistically, DHODH inhibition interferes with oxidative phosphorylation (OXPHOS) and aerobic glycolysis in activated T cells via functional inhibition of complex III of the respiratory chain. The affinity-dependent effects of DHODH inhibition were closely linked to differences in T cell metabolism. High-affinity T cells preferentially use OXPHOS during early activation, which explains their increased susceptibility toward DHODH inhibition. In a mouse model of MS, DHODH inhibitory treatment resulted in preferential inhibition of high-affinity autoreactive T cell clones. Compared to T cells from healthy controls, T cells from patients with RRMS exhibited increased OXPHOS and glycolysis, which were reduced with teriflunomide treatment. Together, these data point to a mechanism of action where DHODH inhibition corrects metabolic disturbances in T cells, which primarily affects profoundly metabolically active high-affinity T cell clones. Hence, DHODH inhibition may promote recovery of an altered T cell receptor repertoire in autoimmunity

LUBAC assembles a ubiquitin signaling platform at mitochondria for signal amplification and transport of NF-κB to the nucleus

Mitochondria are increasingly recognized as cellular hubs to orchestrate signaling pathways that regulate metabolism, redox homeostasis, and cell fate decisions. Recent research revealed a role of mitochondria also in innate immune signaling; however, the mechanisms of how mitochondria affect signal transduction are poorly understood. Here, we show that the NF-κB pathway activated by TNF employs mitochondria as a platform for signal amplification and shuttling of activated NF-κB to the nucleus. TNF treatment induces the recruitment of HOIP, the catalytic component of the linear ubiquitin chain assembly complex (LUBAC), and its substrate NEMO to the outer mitochondrial membrane, where M1- and K63-linked ubiquitin chains are generated. NF-κB is locally activated and transported to the nucleus by mitochondria, leading to an increase in mitochondria-nucleus contact sites in a HOIP-dependent manner. Notably, TNF-induced stabilization of the mitochondrial kinase PINK1 furthermore contributes to signal amplification by antagonizing the M1-ubiquitin-specific deubiquitinase OTULIN. Overall, our study reveals a role for mitochondria in amplifying TNF-mediated NF-κB activation, both serving as a signaling platform, as well as a transport mode for activated NF-κB to the nuclear

Vitamin D and mortality: Individual participant data meta-analysis of standardized 25-hydroxyvitamin D in 26916 individuals from a European consortium

Source at http://doi.org/10.1371/journal.pone.0170791Background:Vitamin D deficiency may be a risk factor for mortality but previous meta-analyses lacked standardization of laboratory methods for 25-hydroxyvitamin D (25[OH]D) concentrations and used aggregate data instead of individual participant data (IPD). We therefore performed an IPD meta-analysis on the association between standardized serum 25(OH)D and mortality.Methods:In a European consortium of eight prospective studies, including seven general population cohorts, we used the Vitamin D Standardization Program (VDSP) protocols to standardize 25(OH)D data. Meta-analyses using a one step procedure on IPD were performed to study associations of 25(OH)D with all-cause mortality as the primary outcome, and with cardiovascular and cancer mortality as secondary outcomes. This meta-analysis is registered at ClinicalTrials.gov, number NCT02438488.Findings:We analysed 26916 study participants (median age 61.6 years, 58% females) with a median 25(OH)D concentration of 53.8 nmol/L. During a median follow-up time of 10.5 years, 6802 persons died. Compared to participants with 25(OH)D concentrations of 75 to 99.99 nmol/L, the adjusted hazard ratios (with 95% confidence interval) for mortality in the 25(OH)D groups with 40 to 49.99, 30 to 39.99, and Interpretation:In the first IPD meta-analysis using standardized measurements of 25(OH)D we observed an association between low 25(OH)D and increased risk of all-cause mortality. It is of public health interest to evaluate whether treatment of vitamin D deficiency prevents premature deaths