Tetrahydrobiopterin modulates ubiquitin conjugation to UBC13/UBE2N and proteasome activity by S-nitrosation

Nitric Oxide (NO) is an intracellular signalling mediator, which affects many biological processes via the posttranslational modification of proteins through S-nitrosation. The availability of NO and NOS-derived reactive oxygen species (ROS) from enzymatic uncoupling are determined by the NO synthase cofactor Tetrahydrobiopterin (BH4). Here, using a global proteomics “biotin-switch” approach, we identified components of the ubiquitin-proteasome system to be altered via BH4-dependent NO signalling by protein S-nitrosation. We show S-nitrosation of ubiquitin conjugating E2 enzymes, in particular the catalytic residue C87 of UBC13/UBE2N, leading to impaired polyubiquitylation by interfering with the formation of UBC13~Ub thioester intermediates. In addition, proteasome cleavage activity in cells also seems to be altered by S-nitrosation, correlating with the modification of cysteine residues within the 19S regulatory particle and catalytic subunits of the 20S complex. Our results highlight the widespread impact of BH4 on downstream cellular signalling as evidenced by the effect of a perturbed BH4-dependent NO-Redox balance on critical processes within the ubiquitin-proteasome system (UPS). These studies thereby uncover a novel aspect of NO associated modulation of cellular homeostasis

Expression of Msx1 and Dlx1 during Dumbo rat head development: Correlation with morphological features

The Dumbo rat possesses some characteristics that evoke several human syndromes, such as Treacher-Collins: shortness of the maxillary, zygomatic and mandibular bones, and low position of the ears. Knowing that many homeobox genes are candidates in craniofacial development, we investigated the involvement of the Msx1 and Dlx1 genes in the Dumbo phenotype with the aim of understanding their possible role in abnormal craniofacial morphogenesis and examining the possibility of using Dumbo rat as an experimental model for understanding abnormal craniofacial development. We studied the expression of these genes during craniofacial morphogenesis by RT-PCR method. We used Dumbo embryos at E12 and E14 and included the Wistar strain as a control. Semi-quantitative PCR analysis demonstrated that Msx1 and Dlx1 are expressed differently between Dumbo and Wistar rats, indicating that their low expression may underly the Dumbo phenotype

A Thirty Million Year-Old Inherited Heteroplasmy

Due to essentially maternal inheritance and a bottleneck effect during early oogenesis, newly arising mitochondrial DNA (mtDNA) mutations segregate rapidly in metazoan female germlines. Consequently, heteroplasmy (i.e. the mixture of mtDNA genotypes within an organism) is generally resolved to homoplasmy within a few generations. Here, we report an exceptional transpecific heteroplasmy (predicting an alanine/valine alloacceptor tRNA change) that has been stably inherited in oniscid crustaceans for at least thirty million years. Our results suggest that this heteroplasmy is stably transmitted across generations because it occurs within mitochondria and therefore escapes the mtDNA bottleneck that usually erases heteroplasmy. Consistently, at least two oniscid species possess an atypical trimeric mitochondrial genome, which provides an adequate substrate for the emergence of a constitutive intra-mitochondrial heteroplasmy. Persistence of a mitochondrial polymorphism on such a deep evolutionary timescale suggests that balancing selection may be shaping mitochondrial sequence evolution in oniscid crustaceans

2019 international consensus on cardiopulmonary resuscitation and emergency cardiovascular care science with treatment recommendations : summary from the basic life support; advanced life support; pediatric life support; neonatal life support; education, implementation, and teams; and first aid task forces

The International Liaison Committee on Resuscitation has initiated a continuous review of new, peer-reviewed, published cardiopulmonary resuscitation science. This is the third annual summary of the International Liaison Committee on Resuscitation International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations. It addresses the most recent published resuscitation evidence reviewed by International Liaison Committee on Resuscitation Task Force science experts. This summary addresses the role of cardiac arrest centers and dispatcher-assisted cardiopulmonary resuscitation, the role of extracorporeal cardiopulmonary resuscitation in adults and children, vasopressors in adults, advanced airway interventions in adults and children, targeted temperature management in children after cardiac arrest, initial oxygen concentration during resuscitation of newborns, and interventions for presyncope by first aid providers. Members from 6 International Liaison Committee on Resuscitation task forces have assessed, discussed, and debated the certainty of the evidence on the basis of the Grading of Recommendations, Assessment, Development, and Evaluation criteria, and their statements include consensus treatment recommendations. Insights into the deliberations of the task forces are provided in the Justification and Evidence to Decision Framework Highlights sections. The task forces also listed priority knowledge gaps for further research

Autoimmune and autoinflammatory mechanisms in uveitis

The eye, as currently viewed, is neither immunologically ignorant nor sequestered from the systemic environment. The eye utilises distinct immunoregulatory mechanisms to preserve tissue and cellular function in the face of immune-mediated insult; clinically, inflammation following such an insult is termed uveitis. The intra-ocular inflammation in uveitis may be clinically obvious as a result of infection (e.g. toxoplasma, herpes), but in the main infection, if any, remains covert. We now recognise that healthy tissues including the retina have regulatory mechanisms imparted by control of myeloid cells through receptors (e.g. CD200R) and soluble inhibitory factors (e.g. alpha-MSH), regulation of the blood retinal barrier, and active immune surveillance. Once homoeostasis has been disrupted and inflammation ensues, the mechanisms to regulate inflammation, including T cell apoptosis, generation of Treg cells, and myeloid cell suppression in situ, are less successful. Why inflammation becomes persistent remains unknown, but extrapolating from animal models, possibilities include differential trafficking of T cells from the retina, residency of CD8(+) T cells, and alterations of myeloid cell phenotype and function. Translating lessons learned from animal models to humans has been helped by system biology approaches and informatics, which suggest that diseased animals and people share similar changes in T cell phenotypes and monocyte function to date. Together the data infer a possible cryptic infectious drive in uveitis that unlocks and drives persistent autoimmune responses, or promotes further innate immune responses. Thus there may be many mechanisms in common with those observed in autoinflammatory disorders

Activation of TRPC6 channels is essential for lung ischaemia–reperfusion induced oedema in mice

Lung ischaemia–reperfusion-induced oedema (LIRE) is a life-threatening condition that causes pulmonary oedema induced by endothelial dysfunction. Here we show that lungs from mice lacking nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (Nox2y/−) or the classical transient receptor potential channel 6 (TRPC6−/−) are protected from LIR-induced oedema (LIRE). Generation of chimeric mice by bone marrow cell transplantation and endothelial-specific Nox2 deletion showed that endothelial Nox2, but not leukocytic Nox2 or TRPC6, are responsible for LIRE. Lung endothelial cells from Nox2- or TRPC6-deficient mice showed attenuated ischaemia-induced Ca2+ influx, cellular shape changes and impaired barrier function. Production of reactive oxygen species was completely abolished in Nox2y/− cells. A novel mechanistic model comprising endothelial Nox2-derived production of superoxide, activation of phospholipase C-γ, inhibition of diacylglycerol (DAG) kinase, DAG-mediated activation of TRPC6 and ensuing LIRE is supported by pharmacological and molecular evidence. This mechanism highlights novel pharmacological targets for the treatment of LIRE

Comparison of performance-based measures among native Japanese, Japanese-Americans in Hawaii and Caucasian women in the United States, ages 65 years and over: a cross-sectional study

BACKGROUND: Japanese (both in Japan and Hawaii) have a lower incidence of falls and of hip fracture than North American and European Caucasians, but the reasons for these differences are not clear. SUBJECTS AND METHODS: A cross-sectional study. We compared neuromuscular risk factors for falls using performance-based measures (chair stand time, usual and rapid walking speed, and grip strength) among 163 Japanese women in Japan, 681 Japanese-American women in Hawaii and 9403 Caucasian women in the United States aged 65 years and over. RESULTS: After adjusting for age, the Caucasian women required about 40% more time to complete 5 chair stands than either group of Japanese. Walking speed was about 10% slower among Caucasians than native Japanese, whereas Japanese-American women in Hawaii walked about 11% faster than native Japanese. Grip strength was greatest in Japan, which may reflect the rural farming district that this sample was drawn from. Additional adjustment for height, weight or body mass index increased the adjusted means of chair stand time and grip strength among Japanese, but the differences remained significant. CONCLUSIONS: Both native Japanese and Japanese-American women in Hawaii performed better than Caucasians on chair stand time and walking speed tests, and native Japanese had greater grip strength than Japanese in Hawaii and Caucasians. The biological implications of these differences in performance are uncertain, but may be useful in planning future comparisons between populations

Bacterial adaptation is constrained in complex communities

© 2020, The Author(s). A major unresolved question is how bacteria living in complex communities respond to environmental changes. In communities, biotic interactions may either facilitate or constrain evolution depending on whether the interactions expand or contract the range of ecological opportunities. A fundamental challenge is to understand how the surrounding biotic community modifies evolutionary trajectories as species adapt to novel environmental conditions. Here we show that community context can dramatically alter evolutionary dynamics using a novel approach that ‘cages’ individual focal strains within complex communities. We find that evolution of focal bacterial strains depends on properties both of the focal strain and of the surrounding community. In particular, there is a stronger evolutionary response in low-diversity communities, and when the focal species have a larger genome and are initially poorly adapted. We see how community context affects resource usage and detect genetic changes involved in carbon metabolism and inter-specific interaction. The findings demonstrate that adaptation to new environmental conditions should be investigated in the context of interspecific interactions

Agents increasing cyclic GMP amplify 5-HT4-elicited positive inotropic response in failing rat cardiac ventricle

Activation of 5-HT4 receptors in failing ventricles elicits a cAMP-dependent positive inotropic response which is mainly limited by the cGMP-inhibitable phosphodiesterase (PDE) 3. However, PDE4 plays an additional role which is demasked by PDE3 inhibition. The objective of this study was to evaluate the effect of cGMP generated by particulate and soluble guanylyl cyclase (GC) on the 5-HT4-mediated inotropic response. Extensive myocardial infarctions were induced by coronary artery ligation in Wistar rats, exhibiting heart failure 6 weeks after surgery. Contractility was measured in left ventricular preparations. Cyclic GMP was measured by EIA. In ventricular preparations, ANP or BNP displayed no impact on 5-HT4-mediated inotropic response. However, CNP increased the 5-HT4-mediated inotropic response as well as the β1-adrenoceptor (β1-AR)-mediated response to a similar extent as PDE3 inhibition by cilostamide. Pretreatment with cilostamide eliminated the effect of CNP. Inhibition of nitric oxide (NO) synthase and soluble GC by l-NAME and ODQ, respectively, attenuated the 5-HT4-mediated inotropic response, whereas the NO donor Sin-1 increased this response. The effects were absent during PDE3 inhibition, suggesting cGMP-dependent inhibition of PDE3. However, in contrast to the effects on the 5-HT4 response, Sin-1 inhibited whereas l-NAME and ODQ enhanced the β1-AR-mediated inotropic response. cGMP generated both by particulate (NPR-B) and soluble GC increases the 5-HT4-mediated inotropic response in failing hearts, probably through inhibition of PDE3. β1-AR and 5-HT4 receptor signalling are subject to opposite regulatory control by cGMP generated by soluble GC in failing hearts. Thus, cGMP from different sources is functionally compartmented, giving differential regulation of different Gs-coupled receptors

Quantitative gait analysis under dual-task in older people with mild cognitive impairment: a reliability study

<p>Abstract</p> <p>Background</p> <p>Reliability of quantitative gait assessment while dual-tasking (walking while doing a secondary task such as talking) in people with cognitive impairment is unknown. Dual-tasking gait assessment is becoming highly important for mobility research with older adults since better reflects their performance in the basic activities of daily living. Our purpose was to establish the test-retest reliability of assessing quantitative gait variables using an electronic walkway in older adults with mild cognitive impairment (MCI) under single and dual-task conditions.</p> <p>Methods</p> <p>The gait performance of 11 elderly individuals with MCI was evaluated using an electronic walkway (GAITRite^®System) in two sessions, one week apart. Six gait parameters (gait velocity, step length, stride length, step time, stride time, and double support time) were assessed under two conditions: single-task (sG: usual walking) and dual-task (dG: counting backwards from 100 while walking). Test-retest reliability was determined using intra-class correlation coefficient (ICC). Gait variability was measured using coefficient of variation (CoV).</p> <p>Results</p> <p>Eleven participants (average age = 76.6 years, SD = 7.3) were assessed. They were high functioning (Clinical Dementia Rating Score = 0.5) with a mean Mini-Mental Status Exam (MMSE) score of 28 (SD = 1.56), and a mean Montreal Cognitive Assessment (MoCA) score of 22.8 (SD = 1.23). Under dual-task conditions, mean gait velocity (GV) decreased significantly (sGV = 119.11 ± 20.20 cm/s; dGV = 110.88 ± 19.76 cm/s; p = 0.005). Additionally, under dual-task conditions, higher gait variability was found on stride time, step time, and double support time. Test-retest reliability was high (ICC>0.85) for the six parameters evaluated under both conditions.</p> <p>Conclusion</p> <p>In older people with MCI, variability of time-related gait parameters increased with dual-tasking suggesting cognitive control of gait performance. Assessment of quantitative gait variables using an electronic walkway is highly reliable under single and dual-task conditions. The presence of cognitive impairment did not preclude performance of dual-tasking in our sample supporting that this methodology can be reliably used in cognitive impaired older individuals.</p