Septin collar formation in budding yeast requires GTP binding and direct phosphorylation by the PAK, Cla4

Assembly at the mother–bud neck of a filamentous collar containing five septins (Cdc3, Cdc10, Cdc11, Cdc12, and Shs1) is necessary for proper morphogenesis and cytokinesis. We show that Cdc10 and Cdc12 possess GTPase activity and appropriate mutations in conserved nucleotide-binding residues abrogate GTP binding and/or hydrolysis in vitro. In vivo, mutants unable to bind GTP prevent septin collar formation, whereas mutants that block GTP hydrolysis do not. GTP binding-defective Cdc10 and Cdc12 form soluble heteromeric complexes with other septins both in yeast and in bacteria; yet, unlike wild-type, mutant complexes do not bind GTP and do not assemble into filaments in vitro. Absence of a p21-activated protein kinase (Cla4) perturbs septin collar formation. This defect is greatly exacerbated when combined with GTP binding-defective septins; conversely, the septin collar assembly defect of such mutants is suppressed efficiently by CLA4 overexpression. Cla4 interacts directly with and phosphorylates certain septins in vitro and in vivo. Thus, septin collar formation may correspond to septin filament assembly, and requires both GTP binding and Cla4-mediated phosphorylation of septins

Regulation of polarised growth in fungi

Polarised growth in fungi occurs through the delivery of secretory vesicles along tracks formed by cytoskeletal elements to specific sites on the cell surface where they dock with a multiprotein structure called the exocyst before fusing with the plasmamembrane. The budding yeast, Saccharomyces cerevisiae has provided a useful model to investigate the mechanisms involved and their control. Cortical markers, provided by bud site selection pathways during budding, the septin ring during cytokinesis or the stimulation of the pheromone response receptors during mating, act through upstream signalling pathways to localise Cdc24, the GEF for the rho family GTPase, Cdc42. Cdc42 in its GTP-bound activates a multiprotein protein complex called the polarisome which nucleates actin cables along which the secretory vesicles are transported to the cell surface. Hyphae can elongate at a rate orders of magnitude faster than the extension of a yeast bud, so understanding hyphal growth will require substantial modification of the yeast paradigm. The rapid rate of hyphal growth is driven by a structure called the Spitzenkörper, located just behind the growing tip and which is rich in secretory vesicles. It is thought that secretory vesicles are delivered to the apical region where they accumulate in the Spitzenkörper. The Spitzenkörper then acts as vesicle supply centre in which vesicles exit the Spitzenkörper in all directions, but because of its proximity, the tip receives a greater concentration of vesicles per unit area than subapical regions. There are no obvious equivalents to the bud site selection pathway to provide a spatial landmark for polarised growth in hyphae. However, an emerging model is the way that the site of polarised growth in the fission yeast, Schizosaccharomyces pombe, is marked by delivery of the kelch repeat protein, Tea1, along microtubules. The relationship of the Spitzenkörper to the polarisome and the mechanisms that promote its formation are key questions that form the focus of current research

A Circular and Bio-based Renovation Strategy for Low-income Neighbourhoods

The impact of climate change is expected to increase in the following decade. Possible effects on the built environment are identified as urban heat stress, air pollution, extreme weather conditions, etc. As a result, there is an increase in disease and mortality specifically in the cities among the vulnerable citizens such as elderly people and children. Moreover, many cities worldwide are in the evolution of urbanization which leads to increased carbon emissions as well as a demand for more material production and waste. Consequently, the construction industry embodies great potential for reaching the energy and carbon mitigation goals. For regeneration of the built environment, the European directives requires for the renovation of existing building stock as quick as possible. In Flemish context, cities stimulate renovation projects on a systematic and planned basis, by defining 'urban renovation districts' which received special financial facilities and subsidizing. Consequently, there is a growing demand for affordable housing in combination with a shortage of qualitative and energy efficient housing opportunities. In the last decades, there has been an intensive effort to develop different retrofit strategies, but there is a lack of comprehensive approach that delivers innovative technical solutions such as circular and bio-based construction methods as a solution to the increased housing demand of vulnerable people. For this purpose, this study combines the efforts of two initiatives, (1) Interreg Circular Bio-Based Construction Industry (CBCI) and (2) the innovative financial policy instrument of subsidy retention for low-income groups (refers to citizens living in poor quality houses with insufficient economic means & social skills to renovate). The study has the ambition to explore the coherence between technical, economical, legal, social aspects for circular urban retrofit strategies. Circular building materials and methods were developed and tested in real-life setting with construction of a prototype living lab (LL) in Technology Campus, Ghent. Depending on the results from the LL, an urban renewal strategy for Flemish districts is proposed by using subsidy retention on macro-economic and social level. The scenario is envisaged as a collective approach with the local community in which the vulnerable users also benefit as direct participants to the research

Thermosensitivity of the Saccharomyces cerevisiae gpp1gpp2 double deletion strain can be reduced by overexpression of genes involved in cell wall maintenance

A Saccharomyces cerevisiae strain in which the GPP1 and GPP2 genes, both encoding glycerol-3-phosphate phosphatase isoforms, are deleted, displays both osmo- and thermosensitive (ts) phenotypes. We isolated genes involved in cell wall maintenance as multicopy suppressors of the gpp1gpp2 ts phenotype. We found that the gpp1gpp2 strain is hypersensitive to cell wall stress such as treatment with β-1,3-glucanase containing cocktail Zymolyase and chitin-binding dye Calcofluor-white (CFW). Sensitivity to Zymolyase was rescued by overexpression of SSD1, while CFW sensitivity was rescued by SSD1, FLO8 and WSC3-genes isolated as multicopy suppressors of the gpp1gpp2 ts phenotype. Some of the isolated suppressor genes (SSD1, FLO8) also rescued the lytic phenotype of slt2 deletion strain. Additionally, the sensitivity to CFW was reduced when the cells were supplied with glycerol. Both growth on glycerol-based medium and overexpression of SSD1, FLO8 or WSC3 had additive suppressing effect on CFW sensitivity of the gpp1gpp2 mutant strain. We also confirmed that the internal glycerol level changed in cells exposed to cell wall perturbation. © 2007 Springer-Verlag

AdipoRon enhances healthspan in middle‐aged obese mice: striking alleviation of myosteatosis and muscle degenerative markers

BackgroundObesity among older adults has increased tremendously. Obesity accelerates ageing and predisposes toage-related conditions and diseases, such as loss of endurance capacity, insulin resistance and features of the metabolicsyndrome. Namely, ectopic lipids play a key role in the development of nonalcoholic fatty liver disease (NAFLD) andmyosteatosis, two severe burdens of ageing and metabolic diseases. Adiponectin (ApN) is a hormone, mainly secretedby adipocytes, which exerts insulin-sensitizing and fat-burning properties in several tissues including the liver and themuscle. Its overexpression also increases lifespan in mice. In this study, we investigated whether an ApN receptor ag-onist, AdipoRon (AR), could slow muscle dysfunction, myosteatosis and degenerative muscle markers in middle-agedobese mice. The effects on myosteatosis were compared with those on NAFLD.MethodsThree groups of mice were studied up to 62 weeks of age: One group received normal diet (ND), another,high-fat diet (HFD); and the last, HFD combined with AR given orally for almost 1 year. An additional group of youngmice under an ND was used. Treadmill tests and micro-computed tomography (CT) were carried out in vivo. Histolog-ical, biochemical and molecular analyses were performed on tissues ex vivo. Bodipy staining was used to assessintramyocellular lipid (IMCL) and lipid droplet morphology.ResultsAR did not markedly alter diet-induced obesity. Yet, this treatment rescued exercise endurance in obese mice(up to 2.4-fold,P<0.05), an event that preceded the improvement of insulin sensitivity. Dorsal muscles and liver den-sities, measured by CT, were reduced in obese mice ( 42% and 109%, respectively,P<0.0001), suggesting fatty in-filtration. This reduction tended to be attenuated by AR. Accordingly, AR significantly mitigated steatosis and cellularballooning at liver histology, thereby decreasing the NALFD activity score ( 30%,P<0.05). AR also strikingly reversedIMCL accumulation either due to ageing in oxidativefibres (types 1/2a, soleus) or to HFD in glycolytic ones (types2x/2b, extensor digitorum longus) ( 50% to 85%,P<0.05 or less). Size of subsarcolemmal lipid droplets, knownto be associated with adverse metabolic outcomes, was reduced as well. Alleviation of myosteatosis resulted from im-proved mitochondrial function and lipid oxidation. Meanwhile, AR halved aged-related accumulation of dysfunctionalproteins identified as tubular aggregates and cylindrical spirals by electron microscopy (P<0.05).ConclusionsLong-term AdipoRon treatment promotes‘healthy ageing’in obese middle-aged mice by enhancing en-durance and protecting skeletal muscle and liver against the adverse metabolic and degenerative effects of ageingand caloric excess.University College de Londres (UCL) de Reino Unido - FSR 2017Société Francophone du Diabète de Francia/Roche Diabetes Care de España 2020National Fund for Scientific Research de Bélgica - FNRS 35275437, 201

Inhibiting the inflammasome with MCC950 counteracts muscle pyroptosis and improves Duchenne muscular dystrophy

Background: Duchenne muscular dystrophy (DMD) is the most common inherited human myopathy. Typically, the secondary process involving severe inflammation and necrosis exacerbate disease progression. Previously, we reported that the NLRP3 inflammasome complex plays a crucial role in this disorder. Moreover, pyroptosis, a form of programmed necrotic cell death, is triggered by NLRP3 via gasdermin D (GSDMD). So far, pyroptosis has never been described either in healthy muscle or in dystrophic muscle. The aim of this study was to unravel the role of NLRP3 inflammasome in DMD and explore a potentially promising treatment with MCC950 that selectively inhibits NLRP3. Methods: Four‐week‐old mdx mice (n=6 per group) were orally treated for 2 months with MCC950 (mdx‐T), a highly potent, specific, small-molecule inhibitor of NLRP3, and compared with untreated (mdx) and wild-type (WT) mice. In vivo functional tests were carried out to measure the global force and endurance of mice. Ex vivo biochemical and molecular analyses were performed to evaluate the pathophysiology of the skeletal muscle. Finally, in vitro tests were conducted on primary cultures of DMD human myotubes. Results: After MCC950 treatment, mdx mice exhibited a significant reduction of inflammation, macrophage infiltration and oxidative stress (-20 to -65%, P<0.05 vs untreated mdx). Mdx‐T mice displayed considerably less myonecrosis (-54%, P<0.05 vs mdx) and fibrosis (-75%, P<0.01 vs mdx). Moreover, a more mature myofibre phenotype, characterized by larger-sized fibres and higher expression of mature myosin heavy chains 1 and 7 was observed. Mdx-T also exhibited enhanced force and resistance to fatigue (+20 to 60%, P<0.05 or less). These beneficial effects resulted from MCC950 inhibition of both active caspase-1 (-46%, P=0.075) and cleaved gasdermin D (N-GSDMD) (-42% in medium-sized-fibres, P<0.001). Finally, the anti-inflammatory action and the anti-pyroptotic effect of MCC950 were also recapitulated in DMD human myotubes. Conclusion: Specific inhibition of the NLRP3 inflammasome can significantly attenuate the dystrophic phenotype. A novel finding of this study is the overactivation of GSDMD, which is hampered by MCC950. This ultimately leads to less inflammation and pyroptosis and to a better muscle maturation and function. Targeting NLRP3 might lead to an effective therapeutic approach for a better management of DMD.Fund for Scientific Research de Bélgica (FNRS)-PDR/T.0026.2

SEPT9 occupies the terminal positions in septin octamers and mediates polymerization-dependent functions in abscission

Mammalian SEPT9 is positioned at the end of septin octamers and is necessary for octamer assembly into polymers necessary for abscission during cytokinesis

I-PREGNO – prevention of unhealthy weight gain and psychosocial stress in families during pregnancy and postpartum using an mHealth enhanced intervention: a study protocol of two cluster randomized controlled trials

Background The transition to parenthood represents a critical life period with psychosocial, and behavioral changes and challenges for parents. This often increases stress and leads to unhealthy weight gain in families, especially in psychosocially burdened families. Although universal and selective prevention programs are offered to families, specific support often fails to reach psychosocially burdened families. Digital technologies are a chance to overcome this problem by enabling a low-threshold access for parents in need. However, there is currently a lack of smartphone-based interventions that are tailored to the needs of psychosocially burdened families. Aims The research project I-PREGNO aims to develop and evaluate a self-guided, smartphone-based intervention in combination with face-to-face counseling delivered by healthcare professionals for the prevention of unhealthy weight gain and psychosocial problems. The intervention is specifically tailored to the needs of psychosocially burdened families during the pregnancy and postpartum period. Methods In two cluster randomized controlled trials in Germany and Austria (N = 400) psychosocially burdened families will be recruited and randomized to i) treatment as usual (TAU), or ii) I-PREGNO intervention (self-guided I-PREGNO app with counseling sessions) and TAU. We expect higher acceptance and better outcomes on parental weight gain and psychosocial stress in the intervention group. Discussion The intervention offers a low cost and low-threshold intervention and considers the life situation of psychosocially burdened families who are a neglected group in traditional prevention programs. After positive evaluation, the intervention may easily be implemented in existing perinatal care structures in European countries such as Germany and Austria. Trial registration Both trials were registered prospectively at the German Clinical Trials Register (Germany: DRKS00029673; Austria: DRKS00029934) in July and August 2022

Dietary intake, physical activity and sedentary behavior and association with BMI during the transition to parenthood: a prospective dyadic study

IntroductionLittle is known on how diet, physical activity (PA) and sedentary behavior (SB) changes during pregnancy and after childbirth in primiparous couples. Moreover, it is unclear how potential behavioral changes are associated with changes in BMI. This study examined changes in diet, PA and SB, and their association with changes in BMI in couples transitioning to parenthood.MethodsDietary intake (FFQ), PA, SB (both Actigraph GT3X accelerometers) and BMI of women and men were assessed at 12 weeks of gestation, 6 weeks and 6 months postpartum. Data were analyzed using dyadic longitudinal data analyses techniques.ResultsIn women, a decrease in fruit intake, an increase in alcohol intake, an increase of light-intensity PA, and a decrease in SB were observed from the beginning of pregnancy up to 6 months postpartum. Decreases in fruit intake between 6 weeks and 6 months postpartum was associated with increases in BMI. Men did not show significant dietary changes, while an increase in light-intensity PA and a decrease in moderate-to-vigorous PA (MVPA) was observed at 6 months postpartum when compared to 12 weeks of gestation. Paternal increases in “avoidance food group” intake were associated with increases in BMI between baseline and 6 weeks postpartum. No associations of changes in BMI and changes in PA and SB were found.DiscussionNot only mothers but also fathers experienced unfavorable changes in lifestyle during the transition to parenthood, with impact on BMI changes. This highlights the need to monitor unhealthy changes in lifestyle and body weight in both parents when expecting a child and after childbirth.Clinical trial registrationClinicaltrials.gov, NCT03454958

Subunit-dependent modulation of septin assembly: Budding yeast septin Shs1 promotes ring and gauze formation

Substitution of specific terminal subunits within septin complexes and septin phosphorylation drive the formation of distinct higher-order septin assemblies in budding yeast