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Discover how PEPperPRINT Peptide Microarray products have been used in different fields of research.

The cellular modifier MOAG-4/SERF drives amyloid formation through charge complementation

Pras, Anita; Houben, Bert; Aprile, Francesco A.; Seinstra, Renée; Gallardo, Rodrigo; Janssen, Leen; Hogewerf, Wytse; Gallrein, Christian; De Vleeschouwer, Matthias; Mata-Cabana, Alejandro; Koopman, Mandy; Stroo, Esther; de Vries, Minke; Louise Edwards, Samantha; Kirstein, Janine; Vendruscolo, Michele; Falsone, Salvatore Fabio; Rousseau, Frederic; Schymkowitz, Joost; Nollen, Ellen A. A.
EMBO J.
Nov 2021
While aggregation-prone proteins are known to accelerate aging and cause age-related diseases, the cellular mechanisms that drive their cytotoxicity remain unresolved. The orthologous proteins MOAG-4, SERF1A, and SERF2 have recently been identified as cellular modifiers of such proteotoxicity. Using a peptide array screening approach on human amyloidogenic proteins, we found that SERF2 interacted with protein segments enriched in negatively charged and hydrophobic, aromatic amino acids. The absence of such segments, or the neutralization of the positive charge in SERF2, prevented these interactions and abolished the amyloid-promoting activity of SERF2. In protein aggregation models in the nematode worm Caenorhabditis elegans, protein aggregation and toxicity were suppressed by mutating the endogenous locus of MOAG-4 to neutralize charge. Our data indicate that MOAG-4 and SERF2 drive protein aggregation and toxicity by interactions with negatively charged segments in aggregation-prone proteins. Such charge interactions might accelerate primary nucleation of amyloid by initiating structural changes and by decreasing colloidal stability. Our study points at charge interactions between cellular modifiers and amyloidogenic proteins as potential targets for interventions to reduce age-related protein toxicity.

HSP70iQ435A to subdue autoimmunity and support anti-tumor responses

Jaishankar, Dinesh; Cosgrove, Cormac; Ramesh, Prathyaya; Mahon, James; Shivde, Rohan; Dellacecca, Emilia R.; Yang, Shiayin F.; Mosenson, Jeffrey; Guevara-Patiño, José A.; Le Poole, I. Caroline
Cell Stress and Chaperones.
Sep 2021
Developing immunosuppressive therapies for autoimmune diseases comes with a caveat that immunosuppression may promote the risk of developing other conditions or diseases. We have previously shown that biolistic delivery of an expression construct encoding inducible HSP70 (HSP70i) with one amino acid modification in the dendritic cell (DC) activating moiety 435–445 (HSP70iQ435A) to mouse skin resulted in significant immunosuppressive activity of autoimmune vitiligo, associated with fewer tissue infiltrating T cells. To prepare HSP70iQ435A as a potential therapeutic for autoimmune vitiligo, in this study we evaluated whether and how biolistic delivery of HSP70iQ435A in mice affects anti-tumor responses. We found that HSP70iQ435A in fact supports anti-tumor responses in melanoma-challenged C57BL/6 mice. Biolistic delivery of the HSP70iQ435A-encoding construct to mice elicited significant anti-HSP70 titers, and anti-HSP70 IgG and IgM antibodies recognize surface-expressed and cytoplasmic HSP70i in human and mouse melanoma cells. A peptide scan revealed that the anti-HSP70 antibodies recognize a specific C-terminal motif within the HSP70i protein. The antibodies elicited surface CD107A expression among mouse NK cells, representative of antibody-mediated cellular cytotoxicity (ADCC), supporting the concept, that HSP70iQ435A-encoding DNA elicits a humoral response to the stress protein expressed selectively on the surface of melanoma cells. Thus, besides limiting autoimmunity and inflammation, HSP70iQ435A elicits humoral responses that limit tumor growth and may be used in conjunction with immune checkpoint inhibitors to not only control tumor but to also limit adverse events following tumor immunotherapy.

Serum Peptide Immunoglobulin G Autoantibody Response in Patients with Different Central Nervous System Inflammatory Demyelinating Disorders

Lee, Hye Lim; Park, Jin-Woo; Seok, Jin Myoung; Jeon, Mi Young; Kim, Hojin; Lim, Young-Min; Shin, Ha Young; Kang, Sa-Yoon; Kwon, Oh-Hyun; Lee, Sang-Soo; Seok, Hung Youl; Min, Ju-Hong; Lee, Sung-Hyun; Kim, Byung-Jo; Kim, Byoung Joon
Diagnostics.
Jul 2021
Previous efforts to discover new surrogate markers for the central nervous system (CNS) inflammatory demyelinating disorders have shown inconsistent results; moreover, supporting evidence is scarce. The present study investigated the IgG autoantibody responses to various viral and autoantibodies-related peptides proposed to be related to CNS inflammatory demyelinating disorders using the peptide microarray method. We customized a peptide microarray containing more than 2440 immobilized peptides representing human and viral autoantigens. Using this, we tested the sera of patients with neuromyelitis optica spectrum disorders (NMOSD seropositive, n = 6; NMOSD seronegative, n = 5), multiple sclerosis (MS, n = 5), and myelin-oligodendrocyte glycoprotein antibody-associated disease (MOGAD, n = 6), as well as healthy controls (HC, n = 5) and compared various peptide immunoglobulin G (IgG) responses between the groups. Among the statistically significant peptides based on the pairwise comparisons of IgG responses in each disease group to HC, cytomegalovirus (CMV)-related peptides were most clearly distinguishable among the study groups. In particular, the most significant differences in IgG response were observed for HC vs. MS and HC vs. seronegative NMOSD (p = 0.064). Relatively higher IgG responses to CMV-related peptides were observed in patients with MS and NMOSD based on analysis of the customized peptide microarray.

Nutrient transceptors physically interact with the yeast S6/protein kinase B homolog, Sch9, a TOR kinase target

Zhang, Zhiqiang; Cottignie, Ines; Van Zeebroeck, Griet; Thevelein, Johan M.
Biochem J.
Jan 2021
Multiple starvation-induced, high-affinity nutrient transporters in yeast function as receptors for activation of the protein kinase A (PKA) pathway upon re-addition of their substrate. We now show that these transceptors may play more extended roles in nutrient regulation. The Gap1 amino acid, Mep2 ammonium, Pho84 phosphate and Sul1 sulfate transceptors physically interact in vitro and in vivo with the PKA-related Sch9 protein kinase, the yeast homolog of mammalian S6 protein kinase and protein kinase B. Sch9 is a phosphorylation target of TOR and well known to affect nutrient-controlled cellular processes, such as growth rate. Mapping with peptide microarrays suggests specific interaction domains in Gap1 for Sch9 binding. Mutagenesis of the major domain affects the upstart of growth upon the addition of L-citrulline to nitrogen-starved cells to different extents but apparently does not affect in vitro binding. It also does not correlate with the drop in L-citrulline uptake capacity or transceptor activation of the PKA target trehalase by the Gap1 mutant forms. Our results reveal a nutrient transceptor–Sch9–TOR axis in which Sch9 accessibility for phosphorylation by TOR may be affected by nutrient transceptor–Sch9 interaction under conditions of nutrient starvation or other environmental challenges.

Mus81-Mms4 endonuclease is an Esc2-STUbL-Cullin8 mitotic substrate impacting on genome integrity

Waizenegger, Anja; Urulangodi, Madhusoodanan; Lehmann, Carl P.; Reyes, Teresa Anne Clarisse; Saugar, Irene; Tercero, José Antonio; Szakal, Barnabas; Branzei, Dana
The Mus81-Mms4 nuclease is activated in G2/M via Mms4 phosphorylation to allow resolution of persistent recombination structures. However, the fate of the activated phosphorylated Mms4 remains unknown. Here we find that Mms4 is engaged by (poly)SUMOylation and ubiquitylation and targeted for proteasome degradation, a process linked to the previously described Mms4 phosphorylation cycle. Mms4 is a mitotic substrate for the SUMO-Targeted Ubiquitin ligase Slx5/8, the SUMO-like domain-containing protein Esc2, and the Mms1-Cul8 ubiquitin ligase. In the absence of these activities, phosphorylated Mms4 accumulates on chromatin in an active state in the next G1, subsequently causing abnormal processing of replication-associated recombination intermediates and delaying the activation of the DNA damage checkpoint. Mus81-Mms4 mutants that stabilize phosphorylated Mms4 have similar detrimental effects on genome integrity. Overall, our findings highlight a replication protection function for Esc2-STUbL-Cul8 and emphasize the importance for genome stability of resetting phosphorylated Mms4 from one cycle to another.

Rapid response to pandemic threats: immunogenic epitope detection of pandemic pathogens for diagnostics and vaccine development using peptide microarrays

Heiss, Kirsten; Heidepriem, Jasmin; Fischer, Nico; Weber, Laura K; Dahlke, Christine; Jaenisch, Thomas; Loeffler, Felix F
J. Proteome Res..
Sep 2020
Emergence and re-emergence of pathogens bearing the risk of becoming a pandemic threat are on the rise. Increased travel and trade, growing population density, changes in urbanization, and climate have a critical impact on infectious disease spread. Currently, the world is confronted with the emergence of a novel coronavirus SARS-CoV-2, responsible for yet more than 500 000 deaths globally. Outbreaks caused by viruses such as SARS-CoV-2, HIV, Ebola, influenza, and Zika have increased over the last decade, underlining the urgent need for a rapid development of diagnostics and vaccines. Hence, the rational identification of biomarkers for diagnostic measures on the one hand, and antigenic targets for vaccine development on the other, are of utmost importance. Peptide microarrays can display large numbers of putative target proteins translated into overlapping linear (and cyclic) peptides. Using these highly diverse libraries, covering tens of thousands of peptides, allow for the in-depth analysis of antibody signatures in a multiplexed, high-throughput fashion. In this review, we highlight synthesis platforms that facilitate fast and highly flexible generation of high-density peptide microarrays. We further outline the multifaceted applications of these peptide array platforms for the development of serological tests and vaccines, to quickly encounter pandemic threats.

Fibrinogen interaction with complement C3: a potential therapeutic target to reduce thrombosis risk

King, Rhodri J.; Schuett, Katharina; Tiede, Christian; Jankowski, Vera; John, Vicky; Trehan, Abhi; Simmons, Katie; Ponnambalam, Sreenivasan; Storey, Robert F.; Fishwick, Colin W.G.; McPherson, Michael J.; Tomlinson, Darren C.; Ajjan, Ramzi A.
Haematologica.
Apr 2020
Complement C3 binds fibrinogen and compromises fibrin clot lysis thereby enhancing thrombosis risk. We investigated the role of fibrinogen-C3 interaction as a novel therapeutic target to reduce thrombosis risk by analysing: i) consistency in the fibrinolytic properties of C3, ii) binding sites between fibrinogen and C3 and iii) modulation of fibrin clot lysis by manipulating fibrinogen-C3 interactions. Purified fibrinogen and C3 from the same individuals (n=24) were used to assess inter-individual variability in the anti-fibrinolytic effects of C3. Microarray screening and molecular modelling evaluated C3 and fibrinogen interaction sites. Novel synthetic conformational proteins, termed Affimers, were used to modulate C3-fibrinogen interaction and fibrinolysis. C3 purified from patients with type 1 diabetes showed enhanced prolongation of fibrinolysis compared with healthy control protein [195±105 and 522±166 seconds, respectively (p=0.04)], with consistent effects but a wider range (5-51% and 5-18% lysis prolongation, respectively). Peptide microarray screening identified 2 potential C3-fibrinogen interactions sites within fibrinogen β chain (residues 424-433, 435-445). One fibrinogen-binding Affimer was isolated that displayed sequence identity with C3 in an exposed area of the protein. This Affimer abolished C3-induced prolongation of fibrinolysis (728±25.1 seconds to 632±23.7 seconds, p=0.005) and showed binding to fibrinogen in the same region that is involved in C3-fibrinogen interactions. Moreover, it shortened plasma clot lysis of patients with diabetes, cardiovascular disease or controls by 7-11%. C3 binds fibrinogen β-chain and disruption of fibrinogen-C3 interaction using Affimer proteins enhances fibrinolysis, which represents a potential novel target tool to reduce thrombosis in high risk individuals.

On‐Chip Neo‐Glycopeptide Synthesis for Multivalent Glycan Presentation

Mende, Marco; Tsouka, Alexandra; Heidepriem, Jasmin; Paris, Grigori; Mattes, Daniela S.; Eickelmann, Stephan; Bordoni, Vittorio; Wawrzinek, Robert; Fuchsberger, Felix F.; Seeberger, Peter H.; Rademacher, Christoph; Delbianco, Martina; Mallagaray, Alvaro; Loeffler, Felix F
Chem. Eur. J..
Apr 2020
Single glycan–protein interactions are often weak, such that glycan binding partners commonly utilize multiple, spatially defined binding sites to enhance binding avidity and specificity. Current array technologies usually neglect defined multivalent display. Laser-based array synthesis technology allows for flexible and rapid on-surface synthesis of different peptides. By combining this technique with click chemistry, neo-glycopeptides were produced directly on a functionalized glass slide in the microarray format. Density and spatial distribution of carbohydrates can be tuned, resulting in well-defined glycan structures for multivalent display. The two lectins concanavalin A and langerin were probed with different glycans on multivalent scaffolds, revealing strong spacing-, density-, and ligand-dependent binding. In addition, we could also measure the surface dissociation constant. This approach allows for a rapid generation, screening, and optimization of a multitude of multivalent scaffolds for glycan binding.

The Myc tag monoclonal antibody 9E10 displays highly variable epitope recognition dependent on neighboring sequence context

Schüchner, Stefan; Behm, Christian; Mudrak, Ingrid; Ogris, Egon
Sci. Signal..
Jan 2020
Epitope tags are short, linear antibody recognition sequences that enable detection of tagged fusion proteins by antibodies. Epitope tag position and neighboring sequences potentially affect its recognition by antibodies, and such context-dependent differences in tag binding may have a wide-ranging effect on data interpretation. We tested by Western blotting six antibodies that recognize the c-Myc epitope tag, including monoclonal antibodies 9E10, 4A6, 9B11, and 71D10 and polyclonal antibodies 9106 and A-14. All displayed context-dependent differences in their ability to detect N- or C-terminal Myc-tagged proteins. In particular, clone 9E10, the most cited Myc-tag antibody, displayed high context-dependent detection variability, whereas others, notably 4A6 and 9B11, showed much less context sensitivity in their detection of Myc-tagged proteins. The very high context sensitivity of 9E10 was further substantiated by peptide microarray analyses. We conclude that recently developed, purpose-made monoclonal antibodies specific for Myc have much more uniform reactivity in diverse assays and are much less context sensitive than is the legacy antibody 9E10.

Immunity to Influenza is dependent on MHC II polymorphism: study with 2 HLA transgenic strains

Luckey, David; Weaver, Eric A.; Osborne, Douglas G.; Billadeau, Daniel D.; Taneja, Veena
Sci Rep.
Dec 2019
Major histocompatibility complex II (MHC II) molecules are involved in antigen presentation and the development of a functional adaptive immune response. Evolutionary selection for MHC molecules that effectively clear infectious agents provides an advantage to humans. However, certain class II molecules are associated with autoimmune diseases. In this study we infected autoimmune-susceptible DRB1*0401.AEo and non-susceptible *0402.AEo mice with H1N1 influenza and determined clearance and protective immunity to H3N2 virus. *0401 mice generated a robust TLR-triggered immune response and cleared H1N1 influenza virus infection. After vaccination and challenge with H1N1, *0401 mice, when challenged with H3N2, generated cross-protective immunity to heterosubtypic H3N2 influenza strain whereas *0402 mice cleared the H1N1 infection but did not generate cross-protective immunity against the H3N2 influenza strain. The intracellular trafficking route of MHCII revealed that *0401 molecules traffic through the late endosome/lysosomes while *0402 molecules traffic into early endosomes. This suggested that trafficking of MHCII could affect the functional output of the innate immune response and clearance of viral infections. Also, DRB1*0401 mice live longer than HLA-DRB1*0402 mice. The study provides a potential hypothesis for evolutionary selection of *0401 molecule, even though it is associated with autoreactivity, which may be dependent on the availability of peptide repertoire of self-antigens.

Probing peptide sequences on their ability to generate affinity sites in molecularly imprinted polymers

Piletska, Elena V; Guerreiro, Antonio; Mersiyanova, Margarita; Cowen, Todd; Canfarotta, Francesco; Piletsky, Stanislav S.; Karim, Kal; Piletsky, Sergey A.
Langmuir.
Dec 2019
An array of 4000 defined and addressable tripeptides on a polymer-coated glass slide is used to synthesize molecularly imprinted polymer (MIP) nanoparticles. This work is undertaken to systematically probe the impact of the peptide sequence on the ability to generate affinity MIPs. The polymer affinity is assessed by measuring the fluorescence of bound MIP nanoparticles at each peptide spot on the surface after washing the array to remove any low-affinity polymer. The generic composition commonly used in the preparation of MIPs against proteins seems to be equally suitable for imprinting hydrophobic and hydrophilic tripeptides. The amino acids frequently contributing to the formation of high-affinity MIPs include T, F, D, N, Y, W, and P. The amino acids that rarely contribute to the formation of high-affinity interactions with MIPs are G, V, A, L, I, and M. These observations are confirmed by computational modeling. The basic technique proposed here may be applicable in optimizing polymer compositions for the production of high-affinity MIPs or, more specifically, for the selection of appropriate amino acid sequences when peptide epitopes are used instead of whole protein imprinting.

Diagnostic Profiling of the Human Public IgM Repertoire With Scalable Mimotope Libraries

Pashov, Anastas; Shivarov, Velizar; Hadzhieva, Maya; Kostov, Victor; Ferdinandov, Dilyan; Heintz, Karen-Marie; Pashova, Shina; Todorova, Milena; Vassilev, Tchavdar; Kieber-Emmons, Thomas; Meza-Zepeda, Leonardo A.; Hovig, Eivind
Front. Immunol..
Dec 2019
Specific antibody reactivities are routinely used as biomarkers, but the antibody repertoire reactivity (igome) profiles are still neglected. Here, we propose rationally designed peptide arrays as efficient probes for these system level biomarkers. Most IgM antibodies are characterized by few somatic mutations, polyspecificity, and physiological autoreactivity with housekeeping function. Previously, probing this repertoire with a set of immunodominant self-proteins provided a coarse analysis of the respective repertoire profiles. In contrast, here, we describe the generation of a peptide mimotope library that reflects the common IgM repertoire of 10,000 healthy donors. In addition, an appropriately sized subset of this quasi-complete mimotope library was further designed as a potential diagnostic tool. A 7-mer random peptide phage display library was panned on pooled human IgM. Next-generation sequencing of the selected phage yielded 224,087 sequences, which clustered in 790 sequence clusters. A set of 594 mimotopes, representative of the most significant sequence clusters, was shown to probe symmetrically the space of IgM reactivities in patients’ sera. This set of mimotopes can be easily scaled including a greater proportion of the mimotope library. The trade-off between the array size and the resolution can be explored while preserving the symmetric sampling of the mimotope sequence and reactivity spaces. BLAST search of the non-redundant protein database with the mimotopes sequences yielded significantly more immunoglobulin J region hits than random peptides, indicating a considerable idiotypic connectivity of the targeted igome. The proof of principle predictors for random diagnoses was represented by profiles of mimotopes. The number of potential reactivity profiles that can be extracted from this library is estimated at more than 1070. Thus, a quasi-complete IgM mimotope library and a scalable representative subset thereof are found to address very efficiently the dynamic diversity of the human public IgM repertoire, providing informationally dense and structurally interpretable IgM reactivity profiles.

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