Mesotrypsin Signature Mutation in a Chymotrypsin C (CTRC) Variant Associated with Chronic Pancreatitis

Human chymotrypsin C (CTRC) protects against pancreatitis by degrading trypsinogen and thereby curtailing harmful intra-pancreatic trypsinogen activation. Loss-of-function mutations in CTRC increase the risk for chronic pancreatitis. Here we describe functional analysis of eight previously uncharacterized natural CTRC variants tested for potential defects in secretion, proteolytic stability, and catalytic activity. We found that all variants were secreted from transfected cells normally, and none suffered proteolytic degradation by trypsin. Five variants had normal enzymatic activity, whereas variant p.R29Q was catalytically inactive due to loss of activation by trypsin and variant p.S239C exhibited impaired activity possibly caused by disulfide mispairing. Surprisingly, variant p.G214R had increased activity on a small chromogenic peptide substrate but was markedly defective in cleaving bovine β-casein or the natural CTRC substrates human cationic trypsinogen and procarboxypeptidase A1. Mutation p.G214R is analogous to the evolutionary mutation in human mesotrypsin, which rendered this trypsin isoform resistant to proteinaceous inhibitors and conferred its ability to cleave these inhibitors. Similarly to the mesotrypsin phenotype, CTRC variant p.G214R was inhibited poorly by eglin C, ecotin, or a CTRC-specific variant of SGPI-2, and it readily cleaved the reactive-site peptide bonds in eglin C and ecotin. We conclude that CTRC variants p.R29Q, p.G214R, and p.S239C are risk factors for chronic pancreatitis. Furthermore, the mesotrypsin-like CTRC variant highlights how the same natural mutation in homologous pancreatic serine proteases can evolve a new physiological role or lead to pathology, determined by the biological context of protease function

Initial Stages of Sodium Deposition onto Au(111) from [MPPip][TFSI]: An In‐Situ STM Study for Sodium‐Ion Battery Electrolytes

Sodium-ion batteries are promising candidates for post-lithium-ion batteries. While sodium has a less negative standard electrode potential compared to lithium, it is still a strong reducing agent. Ionic liquids are suitable solvents for sodium metal batteries, since metallic sodium is very reactive, particularly with water and molecules containing acidic hydrogen atoms. In this study, the initial stages of electrodeposition of sodium on Au(111) from N-methyl-N-propylpiperidinium [MPPip] bis(trifluoromethanesulfonyl)imide [TFSI] were studied using voltammetry and in-situ scanning tunnelling microscopy. Four subsequent underpotential deposition stages were observed: (i) nucleation at the Au(111) reconstruction elbows, followed by (ii) growth of small monoatomically high islands that form (iii) a smooth layer via coalescence, and (iv) further island growth on top of the existing layers. The electrocrystallisation mode changed from smooth layer formation to 3D growth, resulting in cauliflower-like structures. The deposition process was accompanied by simultaneous alloy formation

Electrodeposition of Zinc onto Au(111) and Au(100) from the Ionic Liquid [MPPip][TFSI]

The improvement of rechargeable zinc/air batteries was a hot topic in recent years. Predominantly, the influence of water and additives on the structure of the Zn deposit and the possible dendrite formation were studied. However, the effect of the surface structure of the underlying substrate was not focused on in detail, yet. We now show the differences in electrochemical deposition of Zn onto Au(111) and Au(100) from the ionic liquid N-methyl-N-propylpiperidinium bis(trifluoromethanesulfonyl)imide. The fundamental processes were initially characterized via cyclic voltammetry and in situ scanning tunnelling microscopy. Bulk deposits were then examined using Auger electron spectroscopy and scanning electron microscopy. Different structures of Zn deposits are observed during the initial stages of electrocrystallisation on both electrodes, which reveals the strong influence of the crystallographic orientation on the metal deposition of zinc on gold

Linking complement C3 and B cells in nasal polyposis

Nasal polyposis often is characterized by a persistent inflammation of the sinonasal mucosa, disease recurrence after medical or surgical intervention, and asthma comorbidity. Dysregulated complement activation may contribute to immunologic alterations and disease. To date, there is only scattered knowledge on the source and regulation of the central complement factors in the pathogenesis of nasal polyps. Here, we aim to study complement signatures, especially the C3-C3aR axis, and focus on cellular sources and targets in nasal polyps. Expression of complement factors, including C3, C5, and the anaphylatoxin receptors, was analyzed in nasal polyp tissue samples, the corresponding inferior turbinates, and healthy controls using transcriptomic methods and protein measurements. Distinct patterns of complement expression were found in nasal polyps compared to controls, characterized by an increased C3 activation and an increase in C3aR-bearing cells. In contrast, no difference was shown for epithelial-dependent C3 production. Besides low intracellular C3-expression levels for lymphocytes in general, we could identify an enlarged B lymphocyte population in nasal polyps displaying high amounts of intracellular C3. Our data suggest a prominent role for the C3-C3aR-axis in nasal polyps and, for the first time, describe a B cell population containing high levels of intracellular C3, suggesting a new role of B cells in the maintenance of the inflammation by complement

Evidence for Microchimerism in Baboon Recipients of Pig Hearts

Xenotransplantation, like allotransplantation, is usually associated with microchimerism, i.e., the presence of cells from the donor in the recipient. Microchimerism was reported in first xenotransplantation trials in humans, as well as in most preclinical trials in nonhuman primates (for review, see Denner, Viruses 2023, 15, 190). When using pigs as xenotransplantation donors, their cells contain porcine endogenous retroviruses (PERVs) in their genome. This makes it difficult to discriminate between microchimerism and PERV infection of the recipient. Here, we demonstrate the appropriate virological methods to be used for the identification of microchimerism, first by screening for porcine cellular genes, and then how to detect infection of the host. Using porcine short interspersed nuclear sequences (SINEs), which have hundreds of thousands of copies in the pig genome, significantly increased the sensitivity of the screening for pig cells. Second, absence of PERV RNA demonstrated an absence of viral genomic RNA or expression as mRNA. Lastly, absence of antibodies against PERV proteins conclusively demonstrated an absence of a PERV infection. When applying these methods for analyzing baboons after pig heart transplantation, microchimerism could be demonstrated and infection excluded in all animals. These methods can be used in future clinical trials

Catalytic activity imperative for nanoparticle dose enhancement in photon and proton therapy.

Nanoparticle-based radioenhancement is a promising strategy for extending the therapeutic ratio of radiotherapy. While (pre)clinical results are encouraging, sound mechanistic understanding of nanoparticle radioenhancement, especially the effects of nanomaterial selection and irradiation conditions, has yet to be achieved. Here, we investigate the radioenhancement mechanisms of selected metal oxide nanomaterials (including SiO2, TiO2, WO3 and HfO2), TiN and Au nanoparticles for radiotherapy utilizing photons (150 kVp and 6 MV) and 100 MeV protons. While Au nanoparticles show outstanding radioenhancement properties in kV irradiation settings, where the photoelectric effect is dominant, these properties are attenuated to baseline levels for clinically more relevant irradiation with MV photons and protons. In contrast, HfO2 nanoparticles retain some of their radioenhancement properties in MV photon and proton therapies. Interestingly, TiO2 nanoparticles, which have a comparatively low effective atomic number, show significant radioenhancement efficacies in all three irradiation settings, which can be attributed to the strong radiocatalytic activity of TiO2, leading to the formation of hydroxyl radicals, and nuclear interactions with protons. Taken together, our data enable the extraction of general design criteria for nanoparticle radioenhancers for different treatment modalities, paving the way to performance-optimized nanotherapeutics for precision radiotherapy

Versatile 3D-Printed Micro-Reference Electrodes for Aqueous and Non-Aqueous Solutions

While numerous reference electrodes suitable for aqueous electrolytes exist, there is no well-defined standard for non-aqueous electrolytes. Furthermore, reference electrodes are often large and do not meet the size requirements for small cells. In this work, we present a simple method for fabricating stable 3D-printed micro-reference electrodes. The prints are made from polyvinylidene fluoride, which is chemically inert in strong acids, bases, and commonly used non-aqueous solvents. We chose six different reference systems based on Ag, Cu, Zn, and Na, including three aqueous and three non-aqueous systems to demonstrate the versatility of the approach. Subsequently, we conducted cyclic voltammetry experiments and measured the potential difference between the aqueous homemade reference electrodes and a commercial Ag/AgCl-electrode. For the non-aqueous reference electrodes, we chose the ferrocene redox couple as an internal standard. From these measurements, we deduced that this new class of micro-reference electrodes is leak-tight and shows a stable electrode potential

Enhanced transfer of organic matter to higher trophic levels caused by ocean acidification and its implications for export production : A mass balance approach

Ongoing acidification of the ocean through uptake of anthropogenic CO2 is known to affect marine biota and ecosystems with largely unknown consequences for marine food webs. Changes in food web structure have the potential to alter trophic transfer, partitioning, and biogeochemical cycling of elements in the ocean. Here we investigated the impact of realistic end-of-the-century CO2 concentrations on the development and partitioning of the carbon, nitrogen, phosphorus, and silica pools in a coastal pelagic ecosystem (Gullmar Fjord, Sweden). We covered the entire winter-to-summer plankton succession (100 days) in two sets of five pelagic mesocosms, with one set being CO2 enriched (similar to 760 mu atm pCO(2)) and the other one left at ambient CO2 concentrations. Elemental mass balances were calculated and we highlight important challenges and uncertainties we have faced in the closed mesocosm system. Our key observations under high CO2 were: (1) A significantly amplified transfer of carbon, nitrogen, and phosphorus from primary producers to higher trophic levels, during times of regenerated primary production. (2) A prolonged retention of all three elements in the pelagic food web that significantly reduced nitrogen and phosphorus sedimentation by about 11 and 9%, respectively. (3) A positive trend in carbon fixation (relative to nitrogen) that appeared in the particulate matter pool as well as the downward particle flux. This excess carbon counteracted a potential reduction in carbon sedimentation that could have been expected from patterns of nitrogen and phosphorus fluxes. Our findings highlight the potential for ocean acidification to alter partitioning and cycling of carbon and nutrients in the surface ocean but also show that impacts are temporarily variable and likely depending upon the structure of the plankton food web.Peer reviewe