Patient-Oriented Perspective on Chemokine Receptor Expression and Function in Glioma

Gliomas are severe brain malignancies, with glioblastoma (GBM) being the most aggressive one. Despite continuous efforts for improvement of existing therapies, overall survival remains poor. Over the last years, the implication of chemokines and their receptors in GBM development and progression has become more evident. Recently, large amounts of clinical data have been made available, prompting us to investigate chemokine receptors in GBM from a still-unexplored patient-oriented perspective. This study aims to highlight and discuss the involvement of chemokine receptors—CCR1, CCR5, CCR6, CCR10, CX3CR1, CXCR2, CXCR4, ACKR1, ACKR2, and ACKR3—most abundantly expressed in glioma patients based on the analysis of publicly available clinical datasets. Given the strong intratumoral heterogeneity characterizing gliomas and especially GBM, receptor expression was investigated by glioma molecular groups, by brain region distribution, emphasizing tissue-specific receptor functions, and by cell type enrichment. Our study constitutes a clinically relevant and patient-oriented guide that recapitulates the expression profile and the complex roles of chemokine receptors within the highly diversified glioma landscape. Additionally, it strengthens the importance of patient-derived material for development and precise amelioration of chemokine receptor-targeting therapies.

Theranostics – present and future

Theragnostics in nuclear medicine constitute an essential element of precision medicine. This notion integrates radionuclide diagnostics procedures and radionuclide therapies using appropriate radiopharmaceutics and treatment targeting specific biological pathways or receptors. The term theragnostics should also include another aspect of treatment: not only whether a given radioisotopic drug can be used, but also in what dose it ought to be used. Theragnostic procedures also allow predicting the effects of treatment based on the assessment of specific receptor density or the metabolic profile of neoplastic cells. The future of theragnostics depends not only on the use of new radiopharmaceuticals, but also on new gamma cameras. Modern theragnostics already require unambiguous pharmacokinetic and pharmacodynamic measurements based on absolute values. Only dynamic studies provide such a possibility. The introduction of the dynamic total-body PET-CT will enable this type of measurements characterizing metabolic processes and receptor expression on the basis of Patlak plot.

Neutralising antibody activity against SARS-CoV-2 variants, including Omicron, in an elderly cohort vaccinated with BNT162b2

SARS-CoV-2 variants threaten the effectiveness of tools we have developed to mitigate against serious COVID-19. This is especially true in clinically vulnerable sections of society including the elderly. Using sera from BNT162b2 (Pfizer-BioNTech) vaccinated individuals aged between 70 and 89 (vaccinated with two doses 3-weeks apart) we examined the neutralising antibody (nAb) response to wildtype SARS-CoV-2. Between 3 and 20-weeks post 2nd dose, nAb titres dropped 4.9-fold to a median titre of 21.3 (ND80) with 21.6% of individuals having no detectable nAbs at the later time point. Experiments examining the neutralisation of twenty-one different SARS-CoV-2 variant spike proteins confirmed a significant potential for antigenic escape, especially for the Omicron (BA.1), Beta (B.1.351), Delta (B.1.617.2), Theta (P.3), C.1.2 and B.1.638 variants. Interestingly, however, the recently-emerged sub-lineage AY.4.2 was more efficiently neutralised than parental Delta pseudotypes. Combining pseudotype neutralisation with specific receptor binding domain (RBD) ELISAs we confirmed that changes to position 484 in the spike RBD were predominantly responsible for SARS-CoV-2 nAb escape, although the effect of spike mutations is both combinatorial and additive. Lastly, using sera from the same individuals boosted with a 3rd dose of BNT162b2 we showed that high overall levels of neutralising antibody titre can provide significant levels of cross-protection against Omicron. These data provide evidence that SARS-CoV-2 neutralising antibodies wane over time and that antigenically variable SARS-CoV-2 variants are circulating, highlighting the importance of ongoing surveillance and booster programmes. Furthermore, they provide important data to inform risk assessment of new SARS-CoV-2 variants, such as Omicron, as they emerge.

TLT-1, a Potential Regulator of Inflammatory Pathogenesis in Obesity and Non-Alcoholic Fatty Liver Disease (NAFLD)

Background: Obesity, a nationwide health issue, has related medical costs ranging between $147-210 billion per year in United States and has been associated with a 3.5-fold increased risk of developing NAFLD. In obesity, platelets work in a pleotropic manner with vascular and immune cells to amplify the chronic inflammatory process. Interestingly, studies have demonstrated that platelet numbers and reactivity are increased in obese individuals. The emerging role of activated platelets during obesity induced inflammation introduces the novel concept of platelet targeted therapeutic interventions. Kopec et al, further supports the idea that the mechanism underlying the progression of obesity lies in a platelet mediated pro-inflammatory state, illustrating that there is extravascular fibrin(ogen) deposition, macrophages and inflammatory cytokines within white adipose tissue and liver of mice on western diet. Kopec et al uses a fibrinogen mutant mouse (Fiby390-396 ) which lacks the binding motif for Mac-1 and inhibits the ligand interaction with leukocytes, diminishing inflammation, reducing macrophage counts, reducing weight, protects mice from NAFLD and glucose dysmetabolism. Taken together, all evidence points towards a platelet/fibrinogen/leukocyte pathophysiological mechanism underlying the development of obesity. TREM-Like Transcript-1 (TLT-1) is a platelet specific receptor found in the a-granules of platelets and released to the surface upon platelet activation. TLT-1 is a type 1 receptor that, like the integrin a2bb3, binds fibrinogen and facilitates platelet aggregation . However, although TLT-1 may assist in clot formation and hemostasis to arrest bleeding in a non-inflammatory/nonimmune mediated setting, TLT-1's main association is with regulating inflammatory-derived bleeding. This is demonstrated by increased hemorrhage after inflammatory treatments such as lipopolysaccharide LPS in the treml1 -/- mice as compared to controls. Considering the emerging evidence in support of a platelet-fibrinogen receptor ligand interaction as a key mechanism underlying the development of obesity and that TLT-1, a platelet specific receptor binds fibrinogen and mediates leukocyte trafficking, our laboratory set out to determine whether TLT-1 could be implicated as the main culprit underlying this mechanism. When placed on a western diet, treml1 -/-mice are more prone to weight gain, based on these finding we hypothesize that: The TLT-1/Fibrinogen molecular interaction regulates metabolic inflammation in obesity Aims: Evaluate the effects of western diet on obesity and NAFLD in the treml1 -/- mouse model Methods: TLT-1 (treml1 -/-) - apolipoprotein E (apoe -/-) double null (AT-DKO;n=11) mice and control apoe +/-/treml1 +/- littermate controls (AT-Hets;n=20) were fed western diet for 20 weeks. Plasma samples were collected for adipokine, glucose, insulin, liver enzyme and lipid profiling. Mouse were perfused, liver and adipose tissue were collected for histological analysis. Results: Overall AT-DKO mice gained more weight compared to AT-Hets (12.94±1.90 vs 8.51±1.70 grams p=0.02). Plasma analysis demonstrates that the AT-DKO have higher levels of TNF-a (0.54±0.60 vs 0.118±0.17 pg/ml p=0.03), and IL-10 (2.50±1.40 vs 1.50±2.10 pg/ml p=0.004) compared to littermate controls. Histological analysis of livers illustrates increased lipid vacuoles and inflammatory foci in the AT-DKO mice as compared to controls, while preliminary data is not significant for these differences, liver damage in the AT-DKO was significantly greater as demonstrated by increased AST levels (166.21±91.00 vs 102±68.10 U/L p=0.02). Moreover, the AT-DKO mice had higher levels of ALT, direct bilirubin, cholesterol, pai-1 , triglycerides and lower IL-6 and Adiponectin (Table 1 data not significant). These findings suggest that in the absence of TLT-1 these mice are more prone to liver disfunction , hyperlipidemia and inflammatory alterations. Conclusions: Mutant AT-DKO mice are more prone to obesity and NAFLD compared to littermate controls, suggesting that TLT-1, a platelet gene, plays a surprising role in metabolism. Further investigation could adjudicate TLT-1 administration as a potential therapeutic intervention for prevention and amelioration of Obesity and related pathologies. The current state of this project will be reported here. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

Lipidation of Class IV CdiA Effector Proteins Promotes Target Cell Recognition during Contact-Dependent Growth Inhibition

Contact-dependent growth inhibition (CDI) is a common form of interbacterial competition in which cells use CdiA effectors to deliver toxic proteins into their neighbors. CdiA recognizes target bacteria through specific receptor molecules on the cell surface.

Unconventional Actions of Glycoprotein Hormone Subunits: A Comprehensive Review

The glycoprotein hormones (GPH) are heterodimers composed of a common α subunit and a specific β subunit. They act by activating specific leucine-rich repeat G protein-coupled receptors. However, individual subunits have been shown to elicit responses in cells devoid of the receptor for the dimeric hormones. The α subunit is involved in prolactin production from different tissues. The human chorionic gonadotropin β subunit (βhCG) plays determinant roles in placentation and in cancer development and metastasis. A truncated form of the thyrotropin (TSH) β subunit is also reported to have biological effects. The GPH α- and β subunits are derived from precursor genes (gpa and gpb, respectively), which are expressed in most invertebrate species and are still represented in vertebrates as GPH subunit paralogs (gpa2 and gpb5, respectively). No specific receptor has been found for the vertebrate GPA2 and GPB5 even if their heterodimeric form is able to activate the TSH receptor in mammals. Interestingly, GPA and GPB are phylogenetically and structurally related to cysteine-knot growth factors (CKGF) and particularly to a group of antagonists that act independently on any receptor. This review article summarizes the observed actions of individual GPH subunits and presents the current hypotheses of how these actions might be induced. New approaches are also proposed in light of the evolutionary relatedness with antagonists of the CKGF family of proteins.

Angioedema and Fatty Acids

Angioedema is a life-threatening emergency event that is associated with bradykinin and histamine-mediated cascades. Although bradykinin-mediated angioedema currently has specific therapeutic options, angioedema is sometimes intractable with current treatments, especially histamine-mediated angioedema, suggesting that some other mediators might contribute to the development of angioedema. Fatty acids are an essential fuel and cell component, and act as a mediator in physiological and pathological human diseases. Recent updates of studies revealed that these fatty acids are involved in vascular permeability and vasodilation, in addition to bradykinin and histamine-mediated reactions. This review summarizes each fatty acid’s function and the specific receptor signaling responses in blood vessels, and focuses on the possible pathogenetic role of fatty acids in angioedema.

α1-nAchR-Mediated Signaling Through Lipid Raft Is Required for Nicotine-Induced NLRP3 Inflammasome Activation and Nicotine-Accelerated Atherosclerosis

BackgroundNicotine exerts direct effects on multiple cell types in the cardiovascular system by associating with its high-affinity nicotinic acetylcholine receptors (nAchRs). Lipid raft is a membrane microdomain that recruits various receptors and signaling molecules for coordinating cellular immune response and many others signaling processes. Here, we aim to identify the essential role of lipid raft in mediating nicotine-triggered inflammatory and nicotine-accelerated atherosclerosis, and to figure out the specific receptor of nicotine-induced Nod-like receptor protein 3 (NLRP3) inflammasome activation in macrophage.Methods and ResultsApoE–/– mice were fed with a high-fat diet to build atherosclerosis model. Methyl-β-cyclodextrin was used to interrupt intact lipid raft. We confirmed that nicotine triggered NLRP3 inflammasome activation and induced macrophage migration into atherosclerotic plaque, thus accelerated atherosclerosis in apoE–/– mice fed with a high-fat diet. Mechanically, nicotine increased the expression of α1-nAChR and stimulated the accumulation of α1-nAChR in lipid raft, leading to NLRP3 inflammasome activation in macrophage. Conversely, silencing of α1-nAChR in macrophage sufficiently blocked the pro-inflammasome activation effect of nicotine, indicating that α1-nAChR was the specific receptor for nicotine in triggering NLRP3 inflammasome in macrophage. Furthermore, both the destruction of lipid raft by methyl-β-cyclodextrin and the interference of lipid raft clustering by silencing acid sphingomyelinase reversed nicotine-induced NLRP3 inflammasome activation by reducing the accumulation of α1-nAChR in lipid raft in macrophage, suggesting lipid raft–mediated accumulation of α1-nAChR was the key event in regulating the pro-inflammatory effects of nicotine in macrophage. Importantly, nicotine-induced NLRP3 inflammasome activation and macrophage migration into atherosclerotic plaque were reversed by methyl-β-cyclodextrin, making a significant improvement for atherosclerosis in apoE–/– mice fed with a high-fat diet.Conclusionα1-nAChR-mediated signaling through lipid raft is required for NLRP3 inflammasome activation and pro-atherosclerotic property of nicotine.

Analysing Parallel Strategies to Alter the Host Specificity of Bacteriophage T7

The recognition and binding of host bacteria by bacteriophages is most often enabled by a highly specific receptor–ligand type of interaction, with the receptor-binding proteins (RBPs) of phages being the primary determinants of host specificity. Specifically modifying the RBPs could alter or extend the host range of phages otherwise exhibiting desired phenotypic properties. This study employed two different strategies to reprogram T7 phages ordinarily infecting commensal K12 Escherichia coli strains to infect pathogen-associated K1-capsule-expressing strains. The strategies were based on either plasmid-based homologous recombination or bacteriophage recombineering using electroporated DNA (BRED). Our work pursued the construction of two genetic designs: one replacing the gp17 gene of T7, the other replacing gp11, gp12, and gp17 of T7 with their K1F counterparts. Both strategies displayed successful integration of the K1F sequences into the T7 genome, detected by PCR screening. Multiple methods were utilised to select or enrich for chimeric phages incorporating the K1F gp17 alone, including trxA, host-specificity, and CRISPR-Cas-based selection. Irrespective of the selection method, the above strategy yielded poorly reproducible phage propagation on the new host, indicating that the chimeric phage was less fit than the wild type and could not promote continual autonomous reproduction. Chimeric phages obtained from BRED incorporating gp11-12 and gp17, however, all displayed infection in a 2-stage pattern, indicating the presence of both K1F and T7 phenotypes. This study shows that BRED can be used as a tool to quickly access the potential of new RBP constructs without the need to engineer sustainably replicating phages. Additionally, we show that solely repurposing the primary RBP is, in some cases, insufficient to produce a viable chimeric phage.

Viruses Like Sugars: How to Assess Glycan Involvement in Viral Attachment

The first step of viral infection requires interaction with the host cell. Before finding the specific receptor that triggers entry, the majority of viruses interact with the glycocalyx. Identifying the carbohydrates that are specifically recognized by different viruses is important both for assessing the cellular tropism and for identifying new antiviral targets. Advances in the tools available for studying glycan–protein interactions have made it possible to identify them more rapidly; however, it is important to recognize the limitations of these methods in order to draw relevant conclusions. Here, we review different techniques: genetic screening, glycan arrays, enzymatic and pharmacological approaches, and surface plasmon resonance. We then detail the glycan interactions of enterovirus D68 and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), highlighting the aspects that need further clarification.