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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.

Heterotypic Assembly Mechanism Regulates CHIP E3 Ligase Activity

Das, Aniruddha; Thapa, Pankaj; Santiago, Ulises; Shanmugam, Nilesh; Banasiak, Katarzyna; Dabrowska, Katarzyna; Nolte, Hendrik; Szulc, Natalia A.; Gathungu, Rose M.; Cysewski, Dominik; Krüger, Marcus; Dadlez, Michal; Nowotny, Marcin; Camacho, Carlos J.; Hoppe, Thorsten; Pokrzywa, Wojciech
The E3 ubiquitin ligases CHIP/CHN-1 and UFD-2 team up to accelerate ubiquitin chain formation. However, it remained largely unclear how the high processivity of this E3 set is achieved. Here we studied the molecular mechanism and function of the CHN-1/UFD-2 complex in Caenorhabditis elegans. Our data show that UFD-2 binding promotes the cooperation between CHN-1 and ubiquitin-conjugating E2 enzymes by stabilizing the CHN-1 U-box dimer. The HSP-1 chaperone outcompetes UFD-2 for CHN-1 binding and promotes the auto-inhibited CHN-1 state by acting on the conserved position of the U-box domain. The interaction with UFD-2 enables CHN-1 to efficiently ubiquitinate S-Adenosylhomocysteinase (AHCY-1), an enzyme crucial for lipid metabolism. Our results define the molecular mechanism underlying the synergistic cooperation of CHN-1 and UFD-2 in substrate ubiquitylation.

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.

Molecular mimicry, genetic homology, and gene sharing proteomic “molecular fingerprints” using an EBV (Epstein-Barr virus)-derived microarray as a potential diagnostic method in autoimmune disease

Dreyfus, David H.; Farina, Antonella; Farina, Giuseppina Alessandra
Immunol Res.
Dec 2018
EBV (Epstein-Barr Virus) and other human DNA viruses are associated with autoimmune syndromes in epidemiologic studies. In this work, immunoglobulin G response to EBV-encoded proteins which share regions with human immune response proteins from the human host including ZEBRA (BZLF-1 encoded protein), BALF-2 recombinase expressed primarily during the viral lytic replication cycle, and EBNA-1 (Epstein-Barr Virus Nuclear Antigen) expressed during the viral latency cycle respectively were characterized using a laser-printed micro-array (PEPperprint.com). IgG response to conserved “A/T hooks” in EBV-encoded proteins such as EBNA-1 and the BALF-2 recombinase related to host DNA-binding proteins including RAG-1 recombinase and histones, and EBV-encoded virokines such as the IL-10 homologue BCRF-1 suggest further directions for clinical research. The author suggests that proteomic “molecular fingerprints” of the immune response to viral proteins shared with human immune response genes are potentially useful in early diagnosis and monitoring of autoantibody production and response to therapy in EBV-related autoimmune syndromes.

Regulatory T-cell deficiency leads to pathogenic bullous pemphigoid antigen 230 autoantibody and autoimmune bullous disease

Haeberle, Stefanie; Wei, Xiaoying; Bieber, Katja; Goletz, Stephanie; Ludwig, Ralf J.; Schmidt, Enno; Enk, Alexander H.; Hadaschik, Eva N.
Journal of Allergy and Clinical Immunology.
Dec 2018
Background Autoimmune bullous diseases/dermatoses (AIBDs) are severe autoantibody-mediated skin diseases. The pathogenic relevance of autoreactive CD4+ T cells for the induction of autoantibody production remains to be fully evaluated. Scurfy mice lack functional regulatory T (Treg) cells, experience spontaneous activation of autoreactive CD4+ T cells, and display severe erosive skin lesions suggestive of AIBDs. Objective We sought to determine whether AIBDs develop in Treg cell–deficient scurfy mice. Methods Histology, indirect immunofluorescence (IF) microscopy, direct IF, and ELISA were used to prove the presence of AIBDs in scurfy mice. Monoclonal autoantibodies from sera of scurfy mice were screened by using indirect IF on murine skin, and immunoprecipitation and mass spectrometry were used for target antigen identification, followed by confirmation in modified human embryonic kidney cells and murine keratinocytes. Pathogenicity was determined by injecting the autoantibody into neonatal mice and transferring scurfy CD4+ T cells into nu/nu mice. Results Autoantibodies against different known autoantigens of AIBDs spontaneously develop in scurfy mice. Histology reveals subepidermal blisters, and direct IF of skin of scurfy mice shows a predominant linear staining pattern. The mAb 20B12 shows a linear staining pattern in indirect IF, recognizes the murine hemidesmosomal protein bullous pemphigoid antigen 230 (BP230) as the target antigen, and cross-reacts with human BP230. Purified mAb 20B12 induces subepidermal blisters in neonatal mice. Transfer of scurfy CD4+ T cells is sufficient to induce antibodies with reactivity to AIBD autoantigens and subepidermal blisters in the skin of recipient T cell–deficient nu/nu mice. Conclusion We show that the absence of Treg cells leads to AIBDs by pathogenic autoantibodies targeting BP230.

Potential therapeutic antibodies targeting specific adiponectin isoforms in rheumatoid arthritis

Lee, Yeon-Ah; Hahm, Dae-Hyun; Kim, Jung Yeon; Sur, Bonjun; Lee, Hyun Min; Ryu, Chun Jeih; Yang, Hyung-In; Kim, Kyoung Soo
Arthritis Res Ther.
Oct 2018
Background Different adiponectin isoforms appear to be differentially involved in the pathogenesis of various diseases. The purpose of this study was to generate monoclonal antibodies (mAbs) specific to different adiponectin isoforms and investigate whether these mAbs have potential as therapeutic agents for such diseases. Methods Hybridoma cells producing monoclonal antibodies were generated and screened using enzyme-linked immunosorbent assay and Western blotting for the production of mAbs recognizing human adiponectin isoforms. Results The mAb from hybridoma clone KH7–41 recognized both the middle molecular weight (MMW) (hexamer) and low molecular weight (LMW) (trimer) isoforms of adiponectin in human serum, whereas the KH7–33 mAb detected only MMW (hexamer) adiponectin. The KH4–8 clone recognized both the high molecular weight (HMW) (multimer) and MMW adiponectin isoforms. However, in mouse and rat sera, the abovementioned antibodies recognized only the MMW isomer. These mAbs also recognized adiponectin in various human tissues, such as lung, kidney, and adipose tissues, although the three mAbs had different staining intensities. The mAb from clone KH4–8 effectively inhibited increases in interleukin-6 (IL-6) and IL-8 expression in recombinant adiponectin-stimulated human osteoblasts and human umbilical vein endothelial cells. Also, the mAbs KH7–33 and KH4–8 significantly ameliorated rheumatic symptoms in a collagen-induced arthritis mouse model. This result suggests that these mAb treatments may ameliorate adiponectin-mediated inflammatory response. Conclusions mAbs against human adiponectin isomers can potentially be developed as therapeutic antibodies to target specific detrimental isoforms of adiponectin while maintaining the functions of beneficial isoforms.

Interaction of the Warsaw breakage syndrome DNA helicase DDX11 with the replication fork-protection factor Timeless promotes sister chromatid cohesion

Cortone, Giuseppe; Zheng, Ge; Pensieri, Pasquale; Chiappetta, Viviana; Tatè, Rosarita; Malacaria, Eva; Pichierri, Pietro; Yu, Hongtao; Pisani, Francesca M.
PLoS Genet.
Oct 2018
Establishment of sister chromatid cohesion is coupled to DNA replication, but the underlying molecular mechanisms are incompletely understood. DDX11 (also named ChlR1) is a super-family 2 Fe-S cluster-containing DNA helicase implicated in Warsaw breakage syndrome (WABS). Herein, we examined the role of DDX11 in cohesion establishment in human cells. We demonstrated that DDX11 interacts with Timeless, a component of the replication fork-protection complex, through a conserved peptide motif. The DDX11-Timeless interaction is critical for sister chromatid cohesion in interphase and mitosis. Immunofluorescence studies further revealed that cohesin association with chromatin requires DDX11. Finally, we demonstrated that DDX11 localises at nascent DNA by SIRF analysis. Moreover, we found that DDX11 promotes cohesin binding to the DNA replication forks in concert with Timeless and that recombinant purified cohesin interacts with DDX11 in vitro. Collectively, our results establish a critical role for the DDX11-Timeless interaction in coordinating DNA replication with sister chromatid cohesion, and have important implications for understanding the molecular basis of WABS.

Combinatorial Synthesis of Macromolecular Arrays by Microchannel Cantilever Spotting (µCS)

Atwater, Jordyn; Mattes, Daniela S.; Streit, Bettina; von Bojničić-Kninski, Clemens; Loeffler, Felix F.; Breitling, Frank; Fuchs, Harald; Hirtz, Michael
Adv. Mater..
Aug 2018
Surface-bound microarrays of multiple oligo- and macromolecules (e.g., peptides, DNA) offer versatile options in biomedical applications like drug screening, DNA analysis, or medical diagnostics. Combinatorial syntheses of these molecules in situ can save significant resources in regard to processing time and material use. Furthermore, high feature densities are needed to enable high-throughput and low sample volumes as generally regarded in combinatorial chemistry. Here, a scanning-probe-lithography-based approach for the combinatorial in situ synthesis of macromolecules is presented in microarray format. Feature sizes below 40 µm allow for the creation of high-density arrays with feature densities of 62 500 features per cm2. To demonstrate feasibility of this approach for biomedical applications, a multiplexed array of functional protein tags (HA- and FLAG-tag) is synthesized, and selective binding of respective epitope recognizing antibodies is shown. This approach uses only small amounts of base chemicals for synthesis and can be further parallelized, therefore, opening up a route to flexible, highly dense, and cost-effective microarrays.

Autism-specific maternal autoantibodies produce behavioral abnormalities in an endogenous antigen-driven mouse model of autism

Jones, Karen L.; Pride, Michael C.; Edmiston, Elizabeth; Yang, Mu; Silverman, Jill L.; Crawley, Jacqueline N.; Van de Water, Judy
Mol Psychiatry.
Jun 2018
Immune dysregulation has been noted consistently in individuals with autism spectrum disorder (ASD) and their families, including the presence of autoantibodies reactive to fetal brain proteins in nearly a quarter of mothers of children with ASD versus <1% in mothers of typically developing children. Our lab recently identified the peptide epitope sequences on seven antigenic proteins targeted by these maternal autoantibodies. Through immunization with these peptide epitopes, we have successfully created an endogenous, antigen-driven mouse model that ensures a constant exposure to the salient autoantibodies throughout gestation in C57BL/6J mice. This exposure more naturally mimics what is observed in mothers of children with ASD. Male and female offspring were tested using a comprehensive sequence of behavioral assays, as well as measures of health and development highly relevant to ASD. We found that MAR-ASD male and female offspring had significant alterations in development and social interactions during dyadic play. Although 3-chambered social approach was not significantly different, fewer social interactions with an estrous female were noted in the adult male MAR-ASD animals, as well as reduced vocalizations emitted in response to social cues with robust repetitive self-grooming behaviors relative to saline treated controls. The generation of MAR-ASD-specific epitope autoantibodies in female mice prior to breeding created a model that demonstrates for the first time that ASD-specific antigen-induced maternal autoantibodies produced alterations in a constellation of ASD-relevant behaviors.

Reductionist Approach in Peptide-Based Nanotechnology

Gazit, Ehud
Annu. Rev. Biochem..
Jun 2018
The formation of ordered nanostructures by molecular self-assembly of proteins and peptides represents one of the principal directions in nanotechnology. Indeed, polyamides provide superior features as materials with diverse physical properties. A reductionist approach allowed the identification of extremely short peptide sequences, as short as dipeptides, which could form well-ordered amyloid-like β-sheet-rich assemblies comparable to supramolecular structures made of much larger proteins. Some of the peptide assemblies show remarkable mechanical, optical, and electrical characteristics. Another direction of reductionism utilized a natural noncoded amino acid, α-aminoisobutryic acid, to form short superhelical assemblies. The use of this exceptional helix inducer motif allowed the fabrication of single heptad repeats used in various biointerfaces, including their use as surfactants and DNA-binding agents. Two additional directions of the reductionist approach include the use of peptide nucleic acids (PNAs) and coassembly techniques. The diversified accomplishments of the reductionist approach, as well as the exciting future advances it bears, are discussed.

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