Alternative Pathway Research Articles

Microbial evasion of the complement system: a continuous and evolving story.

The complement system is a fundamental part of the innate immune system that plays a key role in the battle of the human body against invading pathogens. Through its three pathways, represented by the classical, alternative, and lectin pathways, the complement system forms a tightly regulated network of soluble proteins, membrane-expressed receptors, and regulators with versatile protective and killing mechanisms. However, ingenious pathogens have developed strategies over the years to protect themselves from this complex part of the immune system. This review briefly discusses the sequence of the complement activation pathways. Then, we present a comprehensive updated overview of how the major four pathogenic groups, namely, bacteria, viruses, fungi, and parasites, control, modulate, and block the complement attacks at different steps of the complement cascade. We shed more light on the ability of those pathogens to deploy more than one mechanism to tackle the complement system in their path to establish infection within the human host.

Pseudo Four-Component Synthesis of 5,6-Dihydroindolo[2,1-a]isoquinolines.

An easy synthesis of novel highly functionalized 5,6-dihydroindolo[2,1-a]isoquinolines was developed via a pseudo four-component domino reaction of 1-aroyl-3,4-dihydroisoquinolines, terminal α,β-ynones, and malononitrile. The selective formation of this biologically relevant heterocyclic core was achieved using a one-pot approach under microwave irradiation. The formation of the same skeleton through the reaction of 5,6-dihydropyrrolo[2,1-a]isoquinolines with malonic acid dinitrile supports the proposed mechanism, involving the intermediate product of the three-component reaction. Furthermore, the disproval of an alternative reaction pathway, which involved the dimerization of malononitrile followed by three-component transformation, was demonstrated. Introducing the malononitrile dimer as a CH acid resulted in the formation of a different pyrido[3',4':4,5]pyrrolo[2,1-a]isoquinoline core. Additionally, the synthesized 5,6-dihydroindolo[2,1-a]isoquinolines were examined for their photophysical properties, revealing their attractive luminescent characteristics.

The spectrum of thrombotic microangiopathy related to monoclonal gammopathy.

Recent studies showed a high prevalence of monoclonal gammopathy (MG) in patients with thrombotic microangiopathy (TMA) aged over 50years and suggested that complement dysregulation is pivotal for the disease to develop. Here, we studied this premise in seven patients with TMA and coexisting MG. Patients with TMA on kidney biopsy and/or peripheral blood were recruited from the prospective COMPETE cohort (NCT04745195) and Limburg Renal Registry. Patients were screened for complement dysregulation, including genetics/factor H autoantibodies (FHAA) and functional ex vivo testing on microvascular endothelial cells. Seven (8%) out of 84 patients with TMA presented with a coexisting MG. MG clustered in patients aged over 50years (n/N=6/32, 19%). C4 and/or C3 levels were low in three patients, while four patients presented with normal complement levels. None of the patients carried rare variants in complement genes. Massive ex vivo C5b9 formation on the endothelium was noted in one patient; purified IgG from this patient caused massive ex vivo C5b9 formation via the alternative pathway of complement activation, pointing to complement dysregulation in the fluid phase. Kidney biopsies from other nephropathies linked to MG rarely exhibited concurrent TMA (n/N=1/27, 4%). MG clustered in patients with TMA aged over 50 years. TMA and coexisting MG represents a heterogeneous disease spectrum, including a small subset of patients who may present with complement dysregulation.

Filtration and tubular handling of EWE-hC3Nb1, a complement inhibitor nanobody, in wild type mice and a mouse model of proteinuric kidney disease.

Tubular activation and deposition of filtered complement proteins have been implicated in the progression of proteinuric kidney disease. The potent C3b-specific nanobody inhibitor of the alternative pathway, EWE-hC3Nb1, is likely freely filtered in the glomerulus to allow complement inhibition in the tubular lumen and may provide a novel treatment option to prevent tubulointerstitial injury. However, more information on the pharmacokinetic properties and renal tubular handling of EWE-hC3Nb1 nanobody is required for its pharmacological application in relation to kidney disease. Here, we examined the pharmacokinetic properties of free EWE-hC3Nb1 in mouse plasma and urine, following subcutaneous injection in wild-type control and podocin knock out (KO) mice with severe proteinuria. Tubular handling of filtered EWE-hC3Nb1 was assessed by immunohistochemistry (IHC) on kidney tissue from control, proteinuric mice, and KO mice deficient in the proximal tubule endocytic receptor megalin. Rapid plasma absorption and elimination of EWE-hC3Nb1 was observed in both control and proteinuric mice; however, urinary excretion of EWE-hC3Nb1 was markedly increased in proteinuric mice. Urinary EWE-hC3Nb1 excretion was amplified in megalin KO mice, and substantial accumulation of EWE-hC3Nb1 was observed in megalin-expressing renal proximal tubules by IHC. Moreover, free EWE-hC3Nb1 was found to be rapidly cleared from plasma. In conclusion, filtered EWE-hC3Nb1 is reabsorbed by a megalin-dependent process in the proximal tubules. Increased load of filtered proteins in the tubular fluid may inhibit the megalin-dependent uptake of EWE-hC3Nb1 in proteinuric mice. Treatment with EWE-hC3Nb1 may allow investigation of the effects of complement inhibition in the tubular fluid.

Spin-Crossing in the (Z)-Selective Alkyne Semihydrogenation Mechanism Catalyzed by Mo3S4 Clusters: A Density Functional Theory Exploration.

Semihydrogenation of internal alkynes catalyzed by the air-stable imidazolyl amino [Mo3S4Cl3(ImNH2)3]+ cluster selectively affords the (Z)-alkene under soft conditions in excellent yields. Experimental results suggest a sulfur-based mechanism with the formation of a dithiolene adduct through interaction of the alkyne with the bridging sulfur atoms. However, computational studies indicate that this mechanism is unable to explain the experimental outcome: mild reaction conditions, excellent selectivity toward the (Z)-isomer, and complete deuteration of the vinylic positions in the presence of CD3OD and CH3OD. An alternative mechanism that explains the experimental results is proposed. The reaction begins with the hydrogenation of two of the Mo3(μ3-S)(μ-S)3 bridging sulfurs to yield a bis(hydrosulfide) intermediate that performs two sequential hydrogen atom transfers (HAT) from the S-H groups to the alkyne. The first HAT occurs with a spin change from singlet to triplet. After the second HAT, the singlet state is recovered. Although the dithiolene adduct is more stable than the hydrosulfide species, the large energy required for the subsequent H2 addition makes the system evolve via the second alternative pathway to selectively render the (Z)-alkene with a lower overall activation barrier.

Modeling Interfacial Dynamics on Single Atom Electrocatalysts: Explicit Solvation and Potential Dependence.

ConspectusSingle atom electrocatalysts, with noble metal-free composition, maximal atom efficiency, and exceptional reactivity toward various energy and environmental applications, have become a research hot spot in the recent decade. Their simplicity and the isolated nature of the atomic structure of their active site have also made them an ideal model catalyst system for studying reaction mechanisms and activity trends. However, the state of the single atom active sites during electrochemical reactions may not be as simple as is usually assumed. To the contrary, the single atom electrocatalysts have been reported to be under greater influence from interfacial dynamics, with solvent and electrolyte ions perpetually interacting with the electrified active center under an applied electrode potential. These complexities render the activity trends and reaction mechanisms derived from simplistic models dubious.In this Account, with a few popular single atom electrocatalysis systems, we show how the change in electrochemical potential induces nontrivial variation in the free energy profile of elemental electrochemical reaction steps, demonstrate how the active centers with different electronic structure features can induce different solvation structures at the interface even for the same reaction intermediate of the simplest electrochemical reaction, and discuss the implication of the complexities on the kinetics and thermodynamics of the reaction system to better address the activity and selectivity trends. We also venture into more intriguing interfacial phenomena, such as alternative reaction pathways and intermediates that are favored and stabilized by solvation and polarization effects, long-range interfacial dynamics across the region far beyond the contact layer, and the dynamic activation or deactivation of single atom sites under operation conditions. We show the necessity of including realistic aspects (explicit solvent, electrolyte, and electrode potential) into the model to correctly capture the physics and chemistry at the electrochemical interface and to understand the reaction mechanisms and reactivity trends. We also demonstrate how the popular simplistic design principles fail and how they can be revised by including the kinetics and interfacial factors in the model. All of these rich dynamics and chemistry would remain hidden or overlooked otherwise. We believe that the complexity at an electrochemical interface is not a curse but a blessing in that it enables deeper understanding and finer control of the potential-dependent free energy landscape of electrochemical reactions, which opens up new dimensions for further design and optimization of single atom electrocatalysts and beyond. Limitations of current methods and challenges faced by the theoretical and experimental communities are discussed, along with the possible solutions awaiting development in the future.

Microenvironment-optimized GelMA microneedles for interstitial fluid extraction and real-time glucose detection

Microneedle (MN) patches have shown great potential for interstitial fluid (ISF) sampling and subsequent analytes detection, providing an alternative pathway for clinical diagnosis based on blood tests. However, MNs based detection is generally based on separate downstream assays, which cannot provide the detection in real-time. Specifically in the context of glucose monitoring, it is desirable to know the glucose level rapidly so as to guide the subsequent treatment in patients. Here, we designed a double layer MNs patch with the crosslinked gelatin methacryloyl (GelMA) tips loaded with glucose oxidase (GOx), whereas the substrate loaded with horseradish peroxidase (HRP), and 3,3′,5,5′-tetramethylbenzidine (TMB). The MNs tips allow for the ISF sampling and detect the glucose in situ via an enzymatic cascade reaction. We used 3D printing technology for MNs molding, which facilitate the customizable MNs design and optimization. Furthermore, we improved the detection sensitivity and accuracy by optimizing the microenvironment of the GelMA and the concentration of each enzymes. The performance of this MNs patch is validated in extracting and detecting glucose using an agarose gel based skin model. The results showed that within the glucose concentration range of 1.7–21 mmol/L, the MNs patch could accurately measure the unknown glucose concentration through the color values of red, green, and blue (RGB) obtained from scanned images. The all-in-one MNs patch with colorimetric functionality is easy to use and does not require specialized personnel or large-scale equipment support, making it highly promising for clinical translation and providing real -time blood glucose monitoring for patients.

Thrombotic microangiopathy following systemic AAV administration is dependent on anti-capsid antibodies.

BACKGROUNDSystemic administration of adeno-associated virus (AAV) can trigger life-threatening inflammatory responses, including thrombotic microangiopathy (TMA), acute kidney injury due to atypical hemolytic uremic syndrome-like complement activation, immune-mediated myocardial inflammation, and hepatic toxicity.METHODSWe describe the kinetics of immune activation following systemic AAV serotype 9 (AAV9) administration in 38 individuals following 2 distinct prophylactic immunomodulation regimens. Group 1 received corticosteroids and Group 2 received rituximab plus sirolimus in addition to steroids to prevent anti-AAV antibody formation.RESULTSGroup 1 participants had a rapid increase in immunoglobulin M (IgM) and IgG. Increase in D-dimer, decline in platelet count, and complement activation are indicative of TMA. All Group 1 participants demonstrated activation of both classical and alternative complement pathways, as indicated by depleted C4 and elevated soluble C5b-9, Ba, and Bb antigens. Group 2 patients did not have a significant change in IgM or IgG and had minimal complement activation.CONCLUSIONSThis study demonstrates that TMA in the setting of AAV gene therapy is antibody dependent (classical pathway) and amplified by the alternative complement pathway. Critical time points and interventions are identified to allow for management of immune-mediated events that impact the safety and efficacy of systemic gene therapy.

The end game(s) of photosynthetic carbon metabolism.

The year 2024 marks 70 years since the general outline of the carbon pathway in photosynthesis was published. Although several alternative pathways are now known, it is remarkable how many organisms use the reaction sequence described 70 yrs ago, which is now known as the Calvin-Benson cycle or variants such as the Calvin-Benson-Bassham cycle or Benson-Calvin cycle. However, once the carbon has entered the Calvin-Benson cycle and is converted to a 3-carbon sugar, it has many potential fates. This review will examine the last stages of photosynthetic metabolism in leaves. In land plants, this process mostly involves the production of sucrose provided by an endosymbiont (the chloroplast) to its host for use and transport to the rest of the plant. Photosynthetic metabolism also usually involves the synthesis of starch, which helps maintain respiration in the dark and enables the symbiont to supply sugars during both the day and night. Other end products made in the chloroplast are closely tied to photosynthetic CO2 assimilation. These include serine from photorespiration and various amino acids, fatty acids, isoprenoids, and shikimate pathway products. I also describe 2 pathways that can short circuit parts of the Calvin-Benson cycle. These final processes of photosynthetic metabolism play many important roles in plants.

Function and mechanism of GBP1 in the development and progression of cervical cancer

Guanylate binding protein 1 (GBP1) is the most concerned member of the GBP family, which has a series of effects such as anti-infection and anti-angiogenesis. Its role in malignant tumors including cervical cancer is still controversial. We aim to explore the effects of GBP1 on cervical cancer through bioinformatics and related experiments. In this study, we first found that GBP1 was generally expressed in cervical cancer in various online databases and was closely related to immune invasion. Secondly, we used multicolor immunofluorescence technology to verify the expression of GBP1 in cervical cancer tissues and its relationship with immune invasion, and explored its relationship with the prognosis of patients with cervical cancer. Knockdown and overexpression assays of GBP1 in vitro were used to prove GBP1 as a potential oncogene of cervical cancer, and its carcinogenicity was verified by in vivo experiment. In order to explore the potential mechanism of GBP1 in promoting cancer, RNA-seq was performed on GBP1 overexpression and knockdown expression cell lines, and GBP1 knockdown and overexpression were found to be associated with many RNA alternative splicing events, suggesting that GBP1 maybe a RNA binding protein (RBP) which affect the biological characteristics of cervical cancer cells through the alternative splicing pathway. However, the later RNA binding protein immunoprecipitation (RIP) assay proved that GBP1 was not a direct alternative splicing factor, while the co-immunoprecipitation (CoIP)-mass spectroscopy (MS) assay combined with protein protein interaction (PPI) analysis proved that 8 alternative splicing factors including Heterogeneous Nuclear Ribonucleoprotein K (HNRNPK) were interacting proteins of GBP1. Combined with the existing reports and the results of RNA-seq alternative splicing analysis, it is speculated that GBP1 may regulate the alternative splicing of CD44 protein by binding to interacting protein-HNRNPK, and thus play a role in promoting cancer in cervical cancer.

Position paper to facilitate patient access to radiopharmaceuticals: considerations for a suitable pharmaceutical regulatory framework.

Nuclear medicine has made enormous progress in the past decades. However, there are still significant inequalities in patient access among different countries, which could be mitigated by improving access to and availability of radiopharmaceuticals. This paper summarises major considerations for a suitable pharmaceutical regulatory framework to facilitate patient access to radiopharmaceuticals. These include the distinct characteristics of radiopharmaceuticals which require dedicated regulations,considering the impact of the variable complexity of radiopharmaceutical preparation, personnel requirements, manufacturing practices and quality assurance, regulatory authority interfaces, communication and training, as well as marketing authorisation procedures to ensure availability of radiopharmaceuticals. Finally, domestic and regional supply to ensure patient access via alternative regulatory pathways, including in-house production of radiopharmaceuticals, is described, and an outlook on regulatory challenges faced by new developments, such as the use of alpha emitters, is provided. All these considerations are an outcome of a dedicated Technical Meeting organised by the IAEA in 2023 and represent the views and opinions of experts in the field, not those of any regulatory authorities.

Usefulness and analytical performances of complement multiplex assay for measuring complement biomarkers in plasma

IntroductionThe complement system is involved in numerous diseases, through diverse mechanisms and degree of activation. With the emergence of complement targeting therapeutic, simple and accessible tools to evaluate the extent of complement activation are strongly needed. MethodsWe evaluated two multiplex panels, measuring complement activation fragments (C4a, C3a, C5a, Bb, Ba, sC5b9) and intact components or regulators (C1q, C2, C3, C4, C5, FD, FP, FH, FI). The specificity of each measurement was assessed by using complement proteins depleted sera and plasma collected from patients with complement deficiencies. Normal values distribution was estimated using 124 plasma samples from healthy donors and complement activation profile was assessed in plasma collected from 31 patients with various complement-mediated disorders. ResultsWe observed good inter-assay variation. All tested protein deficiencies were accurately detected. We established assay-specific reference values for each analyte. Except for C3, C4 and C4a, the majority of the measurements were in good agreement with references methods or published data. ConclusionOur study substantiates the utility of the Complement Multiplex assay as a tool for measuring complement activation and deficiencies. Quantifying complement cleavage fragments in patients exhibiting classical or alternative pathway activation allowed evaluating the activation state of the whole cascade.

Reassessing the need for carbon dioxide removal: moral implications of alternative climate target pathways

Abstract Non-technical summary Scenarios compatible with the Paris agreement's temperature goal of 1.5 °C involve carbon dioxide removal measures – measures that actively remove CO2 from the atmosphere – on a massive scale. Such large-scale implementations raise significant ethical problems. Van Vuuren et al. (2018), as well as the current IPCC scenarios, show that reduction in energy and or food demand could reduce the need for such activities. There is some reluctance to discuss such societal changes. However, we argue that policy measures enabling societal changes are not necessarily ethically problematic. Therefore, they should be discussed alongside techno-optimistic approaches in any kind of discussions about how to respond to climate change. Technical summary The 1.5 °C goal has given impetus to carbon dioxide removal (CDR) measures, such as bioenergy combined with carbon capture and storage, or afforestation. However, land-based CDR options compete with food production and biodiversity protection. Van Vuuren et al. (2018) looked at alternative pathways including lifestyle changes, low-population projections, or non-CO2 greenhouse gas mitigation, to reach the 1.5 °C temperature objective. Underlined by the recently published IPCC AR6 WGIII report, they show that demand-side management measures are likely to reduce the need for CDR. Yet, policy measures entailed in these scenarios could be associated with ethical problems themselves. In this paper, we therefore investigate ethical implications of four alternative pathways as proposed by Van Vuuren et al. (2018). We find that emission reduction options such as lifestyle changes and reducing population, which are typically perceived as ethically problematic, might be less so on further inspection. In contrast, options associated with less societal transformation and more techno-optimistic approaches turn out to be in need of further scrutiny. The vast majority of emission reduction options considered are not intrinsically ethically problematic; rather everything rests on the precise implementation. Explicitly addressing ethical considerations when developing, advancing, and using integrated assessment scenarios could reignite debates about previously overlooked topics and thereby support necessary societal discourse. Social media summary Policy measures enabling societal changes are not necessarily as ethically problematic as commonly presumed and reduce the need for large-scale CDR.

De-stabilizing innate immunity in COVID-19: effects of its own positive feedback and erratic viraemia on the alternative pathway of complement.

Complement provides powerful, fast responses in the human circulation to SARS-CoV-2 (COVID-19 virus) infection of the lower respiratory tract. COVID-19 effects were investigated in a revised human in silico Mass Action model of complement's alternative pathway (AP) responses. Bursts of newly circulating virions increased the fission of Complement protein C3 into C3a and C3b via stimulation of the lectin pathway or inhibited complement factor H. Viral reproduction sub-models incorporated smoothly exponential or step-wise exponential growth. Starting complement protein concentrations were drawn randomly from published normal male or female ranges and each infection model run for 10 days. C3 and factor B (FB) syntheses driven by Lectin Pathway stimulation led to declining plasma C3 and increasing FB concentrations. The C3-convertase concentration, a driver of viral elimination, could match viral growth over three orders of magnitude but near-complete exhaustion of circulating C3 was more prevalent with step-wise than with 'smooth' increases in viral stimulation. C3 exhaustion could be prolonged. Type 2 Diabetes and hypertension led to greatly increased peak C3-convertase concentrations, as did short-term variability of COVID-19 viraemia, pulmonary capillary clotting and secondary acidosis. Positive feedback in the AP greatly extends its response range at the expense of stability.

Selective induction of Rab9-dependent alternative mitophagy using a synthetic derivative of isoquinoline alleviates mitochondrial dysfunction and cognitive deficits in Alzheimer's disease models.

Rationale: Promotion of mitophagy is considered a promising strategy for the treatment of neurodegenerative diseases including Alzheimer's disease (AD). The development of mitophagy-specific inducers with low toxicity and defined molecular mechanisms is essential for the clinical application of mitophagy-based therapy. The aim of this study was to investigate the potential of a novel small-molecule mitophagy inducer, ALT001, as a treatment for AD. Methods: ALT001 was developed through chemical optimization of an isoquinolium scaffold, which was identified from a chemical library screening using a mitophagy reporter system. In vitro and in vivo experiments were conducted to evaluate the potential of ALT001 as a mitophagy-targeting therapeutic agent and to investigate the molecular mechanisms underlying ALT001-induced mitophagy. The therapeutic effect of ALT001 was assessed in SH-SY5Y cells expressing mutant APP and mouse models of AD (5×FAD and PS2APP) by analyzing mitochondrial dysfunction and cognitive defects. Results: ALT001 specifically induces mitophagy both in vitro and in vivo but is nontoxic to mitochondria. Interestingly, we found that ALT001 induces mitophagy through the ULK1-Rab9-dependent alternative mitophagy pathway independent of canonical mitophagy pathway regulators such as ATG7 and PINK1. Importantly, ALT001 reverses mitochondrial dysfunction in SH-SY5Y cells expressing mutant APP in a mitophagy-dependent manner. ALT001 induces alternative mitophagy in mice and restores the decreased mitophagy level in a 5×FAD AD model mouse. In addition, ALT001 reverses mitochondrial dysfunction and cognitive defects in the PS2APP and 5×FAD AD mouse models. AAV-mediated silencing of Rab9 in the hippocampus further confirmed that ALT001 exerts its therapeutic effect through alternative mitophagy. Conclusion: Our results highlight the therapeutic potential of ALT001 for AD via alleviation of mitochondrial dysfunction and indicate the usefulness of the ULK1-Rab9 alternative mitophagy pathway as a therapeutic target.

Cost-effectiveness analysis of upadacitinib as a treatment option for patients with rheumatoid arthritis in the Kingdom of Saudi Arabia

Aim To evaluate cost-effectiveness of upadacitinib (targeted synthetic-disease modifying anti-rheumatic drug [ts-DMARD]) as first-line (1 L) treatment versus current treatment among patients with rheumatoid arthritis (RA) in the Kingdom of Saudi Arabia (KSA), who had an inadequate response to prior conventional-synthetic (csDMARDs) and/or biologic-DMARDs (bDMARDs). Methods This Excel-based model included patients with moderate (Disease Activity Score [DAS28]: >3.2 to ≤5.1) or severe RA (DAS28 > 5.1). Cost-effectiveness of current treatment (1 L: adalimumab-originator/biosimilar; second-line (2 L): other bDMARDs/tofacitinib) was compared against a new treatment involving two scenarios (1 L: upadacitinib, 2 L: adalimumab-biosimilar [scenario-1]/adalimumab-originator [scenario-2]) for a 10-year time-horizon from societal perspective. Model outcomes included direct and indirect costs, quality-adjusted life-years (QALYs), hospitalization days, number of orthopedic surgeries, and incremental cost-utility ratio (ICUR) per QALY. Results With the current pathway, estimated total societal costs for 100 RA patients over 10-year period were Saudi Riyal (SAR) 50,450,354 (United States dollars [USD] 13,453,428) (moderate RA) and SAR50,013,945 (USD13,337,052) (severe RA). New pathway (scenario-1) showed that in patients with moderate-to-severe RA, upadacitinib led to higher QALY gain (+8.99 and +15.63) at lower societal cost (cost difference: -SAR2,023,522 [-USD539,606] and -SAR3,373,029 [-USD899,474], respectively). Thus, as 1 L, upadacitinib projects “dominant” ICUR per QALY over current pathway. Moreover, in alternate pathway (scenario-2), upadacitinib also projects “dominant” ICUR per QALY for patient with severe RA (QALY gain: +15.63; cost difference: -SAR 164,536 [-USD43,876]). However, moderate RA was associated with additional cost of SAR1,255,696 (USD334,852) for improved QALY (+8.99) over current pathway (ICUR per QALY: SAR139,742 [USD37,264]). Both scenarios resulted in reduced hospitalization days (scenario-1: −14.83 days; scenario-2: −11.41 days) and number of orthopedic surgeries (scenario-1: −8.36; scenario-2: −6.54) for moderate-to-severe RA over the current treatment pathway. Conclusion Upadacitinib as 1 L treatment in moderate-to-severe RA can considerably reduce healthcare resource burden in KSA, majorly due to reduced drug administration/monitoring/hospitalization/surgical and indirect costs.

A quantum mechanical approach to the oxidation mechanism of graphene oxide (GO)

Elucidation of the reaction mechanism concerning the oxidation above the face and at the edge of a large, oxidized graphene (GO) cluster, namely C80H22O, by molecular oxygen in the first excited state (1Δg) was achieved with quantum mechanical calculations using the ONIOM two-layer method. Oxidation on the face of the aforementioned cluster leads to the formation of an ozone molecule, whereas oxygen molecule attack at the edge of the oxidized graphene surface either launches an ozonide —a five-membered ring species— formation during its outward approach or an 1,3-dioxetane —a four-membered ring species— production along its inward invasion. A detailed examination of the proposed pathways suggests that the ozonide formation should overcome almost one and a half times an adiabatic energy barrier with respect to the ozone production and is strongly exergonic by up to −50.1 kcal mol−1, supporting the experimental findings that both compounds are critically involved in the explosive deoxygenation of GO. On the other hand, the 1,3-dioxetane alternative pathway is considered even more exergonic, although it requires an overwhelming adiabatic energy barrier of 29.8 kcal mol−1 to accomplish its target.

Deciphering the impacts of modulating the Wnt-planar cell polarity (PCP) pathway on alveolar repair.

Many adult lung diseases involve dysregulated lung repair. Deciphering the molecular and cellular mechanisms that govern intrinsic lung repair is essential to develop new treatments to repair/regenerate the lungs. Aberrant Wnt signalling is associated with lung diseases including emphysema, idiopathic pulmonary fibrosis and pulmonary arterial hypertension but how Wnt signalling contributes to these diseases is still unclear. There are several alternative pathways that can be stimulated upon Wnt ligand binding, one of these is the Planar Cell Polarity (PCP) pathway which induces actin cytoskeleton remodelling. Wnt5a is known to stimulate the PCP pathway and this ligand is of particular interest in regenerative lung biology because of its association with lung diseases and its role in the alveolar stem cell niche. To decipher the cellular mechanisms through which Wnt5a and the PCP pathway affect alveolar repair we utilised a 3-D ex-vivo model of lung injury and repair, the AIR model. Our results show that Wnt5a specifically enhances the alveolar epithelial progenitor cell population following injury and surprisingly, this function is attenuated but not abolished in Looptail (Lp) mouse lungs in which the PCP pathway is dysfunctional. However, Lp tracheal epithelial cells show reduced stiffness and Lp alveolar epithelial cells are less migratory than wildtype (WT), indicating that Lp lung epithelial cells have a reduced capacity for repair. These findings provide important mechanistic insight into how Wnt5a and the PCP pathway contribute to lung repair and indicate that these components of Wnt signalling may be viable targets for the development of pro-repair treatments.

Modulation of Aβ 16-22 aggregation by glucose.

The self-assembly of amyloid-beta (Aβ) peptides into fibrillar structures in the brain is a signature of Alzheimer's disease. Recent studies have reported correlations between Alzheimer's disease and type-2 diabetes. Structurally, hyperglycemia induces covalent protein crosslinkings by advanced glycation end products (AGE), which can affect the stability of Aβ oligomers. In this work, we leverage physics-based coarse-grained molecular simulations to probe alternate thermodynamic pathways that affect peptide aggregation propensities at varying concentrations of glucose molecules. Similar to previous experimental reports, our simulations show a glucose concentration-dependent increase in Aβ aggregation rates, without changes in the overall secondary structure content. We discovered that glucose molecules prefer partitioning onto the aggregate-water interface at a specific orientation, resulting in a loss of molecular rotational entropy. This effectively hastens the aggregation rates, as peptide self-assembly can reduce the available surface area for peptide-glucose interactions. This work introduces a new thermodynamic-driven pathway, beyond chemical cross-linking, that can modulate Aβ aggregation.

Complement in ANCA vasculitis, insights on pathophysiology and targeted therapies

Antineutrophil cytoplasmic antibody (ANCA) associated vasculitis (AAV) is a debilitating disease with the potential to cause significant morbidity and mortality if not treated. The pathogenesis of this disease is not understood, though emerging evidence suggests that alternative complement pathway system is involved. C5a, mediates several pro-inflammatory effects through its receptor C5aR. Avacopan, targets C5a by preventing it from binding to its receptor C5aR. Complement dysregulation, imbalance between regulatory activity of Factor H and stimulation by Factor H related proteins, has been identified as a new mechanism of disease.