Selective inhibition of intestinal guanosine 3,5-cyclic monophosphate signaling by small-molecule protein kinase inhibitors

The guanosine 3,5-cyclic monophosphate (cGMP)-dependent protein kinase II (cGKII) serine/threonine kinase relays signaling through guanylyl cyclase C (GCC) to control intestinal fluid homeostasis. Here, we report the discovery of small-molecule inhibitors of cGKII. These inhibitors were imidazole-aminopyrimidines, which blocked recombinant human cGKII at submicromolar concentrations but exhibited comparatively little activity toward the phylogenetically related protein kinases cGKI and cAMP-dependent protein kinase (PKA). Whereas aminopyrimidyl motifs are common in protein kinase inhibitors, molecular modeling of these imidazole-aminopyrimidines in the ATP-binding pocket of cGKII indicated an unconventional binding mode that directs their amine substituent into a narrow pocket delineated by hydrophobic residues of the hinge and the C-helix. Crucially, this set of residues included the Leu-530 gatekeeper, which is not conserved in cGKI and PKA. In intestinal organoids, these compounds blocked cGKII-dependent phosphorylation of the vasodilator-stimulated phosphoprotein (VASP). In mouse small intestinal tissue, cGKII inhibition significantly attenuated the anion secretory response provoked by the GCC-activating bacterial heat-stable toxin (STa), a frequent cause of infectious secretory diarrhea. In contrast, both PKA-dependent VASP phosphorylation and intestinal anion secretion were unaffected by treatment with these compounds, whereas experiments with T84 cells indicated that they weakly inhibit the activity of cAMP-hydrolyzing phosphodiesterases. As these protein kinase inhibitors are the first to display selective inhibition of cGKII, they may expedite research on cGMP signaling and may aid future development of therapeutics for managing diarrheal disease and other pathogenic syndromes that involve cGKII

An explorative qualitative study to determine the footwear needs of workers in standing environments

Background: Many work places require standing for prolonged periods of time and are potentially damaging to health, with links to musculoskeletal disorders and acute trauma from workplace accidents. Footwear provides the only interaction between the body and the ground and therefore a potential means to impact musculoskeletal disorders. However, there is very limited research into the necessary design and development of footwear based on both the physical environmental constraints and the personal preference of the workers. Therefore, the purpose of this study is to explore workers needs for footwear in the ‘standing’ workplace in relation to MSD, symptoms, comfort and design. Method: Semi-structured interviews were conducted with participants from demanding work environments that require standing for high proportions of the working day. Thematic analysis was used to analyse the results and gain an exploratory understanding into the footwear needs of these workers. Results: Interviews revealed the environmental demands and a very high percentage of musculoskeletal disorders, including day to day discomfort and chronic problems. It was identified that when designing work footwear for standing environments, the functionality of the shoe for the environment must be addressed, the sensations and symptoms of the workers taken into account to encourage adherence and the decision influencers should be met to encourage initial footwear choice. Meeting all these criteria could encourage the use of footwear with the correct safety features and comfort. Development of the correct footwear and increased education regarding foot health and footwear choice could help to reduce or improve the effect of the high number of musculoskeletal disorders repeatedly recorded in jobs that require prolonged periods of standing. Conclusion: This study provides a unique insight into the footwear needs of some workers in environments that require prolonged standing. This user based enquiry has provided information which is important to workplace footwear design

The Biomechanics And Ergonomics Of The Impact Of Anti-Fatigue Mats On Decreasing Whole Body Vibration

The standardization effort in vibration’s field has unfolded the interests of industries. This research aimed at better understanding of the impact of vibration on human body. In the past years, healthcare centers and manufacturers started to equip the workplace with Anti-fatigue Mats (AFM) for the improvement of the working conditions and quality at work. This study analyzed the impact of AFM on the reduction of vibrations transmitted during the weekly activity of manufacturing workers. Seven AFM marketed by Notrax Premium Superior Manufacturing Group were tested. The laser vibrometry technique was used in order to measure vibratory displacements at various points. Under the effect of the vibrations, AFM behaved differently according to their structure and geometries. In comparison, the values obtained showed that AFM absorbed the vibration. It permitted to decrease the risks of ligamentous, or articular pathologies, which can affect employees at work. Taking into account, different results obtained showing that AFM could be used effectively in different areas of workplace, such as in medical or manufacturing settings, in order to improve working conditions

Rescue of chloride and bicarbonate transport by elexacaftor-ivacaftor-tezacaftor in organoid-derived CF intestinal and cholangiocyte monolayers

Background: In cystic fibrosis (CF), loss of CF transmembrane conductance regulator (CFTR)-dependent bicarbonate secretion precipitates the accumulation of viscous mucus in the lumen of respiratory and gastrointestinal epithelial tissues. We investigated whether the combination of elexacaftor (ELX), ivacaftor (IVA) and tezacaftor (TEZ), apart from its well-documented effect on chloride transport, also restores Phe508del-CFTR-mediated bicarbonate transport. Methods: Epithelial monolayers were cultured from intestinal and biliary (cholangiocyte) organoids of homozygous Phe508del-CFTR patients and controls. Transcriptome sequencing was performed, and bicarbonate and chloride transport were assessed in the presence or absence of ELX/IVA/TEZ, using the intestinal current measurement technique. Results: ELX/IVA/TEZ markedly enhanced bicarbonate and chloride transport across intestinal epithelium. In biliary epithelium, it failed to enhance CFTR-mediated bicarbonate transport but effectively rescued CFTR-mediated chloride transport, known to be requisite for bicarbonate secretion through the chloride-bicarbonate exchanger AE2 (SLC4A2), which was highly expressed by cholangiocytes. Biliary but not intestinal epithelial cells expressed an alternative anion channel, anoctamin-1/TMEM16A (ANO1), and secreted bicarbonate and chloride upon purinergic receptor stimulation. Conclusions: ELX/IVA/TEZ has the potential to restore both chloride and bicarbonate secretion across CF intestinal and biliary epithelia and may counter luminal hyper-acidification in these tissues