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

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Binding epitope for recognition of human TRPM4 channel by monoclonal antibody M4M

Wei, Shunhui; Behn, Julian; Poore, Charlene Priscilla; Low, See Wee; Nilius, Bernd; Fan, Hao; Liao, Ping
Sci Rep.
Nov 2022
10.1038/s41598-022-22077-4
Abstract Mouse monoclonal antibody M4M was recently designed to block human TRPM4 channel. The polypeptide for generating M4M is composed of peptide A1 between the transmembrane segment 5 (S5) and the pore, and a second peptide A2 between the pore and the transmembrane segment 6 (S6). Using peptide microarray, a 4-amino acid sequence EPGF within the A2 was identified to be the binding epitope for M4M. Substitution of EPGF with other amino acids greatly reduced binding affinity. Structural analysis of human TRPM4 structure indicates that EPGF is located externally to the channel pore. A1 is close to the EPGF binding epitope in space, albeit separated by a 37-amino acid peptide. Electrophysiological study reveals that M4M could block human TRPM4, but with no effect on rodent TRPM4 which shares a different amino acid sequence ERGS for the binding motif. Our results demonstrate that M4M is a specific inhibitor for human TRPM4.

Targeting FLT3 by new-generation antibody-drug-conjugate in combination with kinase inhibitors for treatment of AML

Roas, Maike; Vick, Binje; Kasper, Marc-André; Able, Marina; Polzer, Harald; Gerlach, Marcus; Kremmer, Elisabeth; Hecker, Judith S.; Schmitt, Saskia; Stengl, Andreas; Waller, Verena; Hohmann, Natascha; Festini, Moreno; Ludwig, Alexander Edmund; Rohrbacher, Lisa; Herold, Tobias; Subklewe, Marion; Götze, Katharina S.; Hackenberger, Christian P.R.; Schumacher, Dominik; Helma-Smets, Jonas; Jeremias, Irmela; Leonhardt, Heinrich; Spiekermann, Karsten
Aug 2022
10.1182/blood.2021015246
Fms like tyrosine kinase 3 (FLT3) is often overexpressed or constitutively activated by internal tandem duplication (ITD) and tyrosine kinase domain (TKD) mutations in acute myeloid leukemia (AML). Despite the use of receptor tyrosine kinase inhibitors (TKI) in FLT3-ITD positive AML, the prognosis of patients is still poor and further improvement of therapy is required. Targeting FLT3 independent of mutations by antibody‑drug‑conjugates (ADCs) is a promising strategy for AML therapy. Here, we report the development and preclinical characterization of a novel FLT3‑targeting ADC, 20D9-ADC, which was generated by applying the innovative P5 conjugation technology. In vitro, 20D9‑ADC mediated potent cytotoxicity to Ba/F3 cells expressing transgenic FLT3 or FLT3-ITD, to AML cell lines and to FLT3-ITD positive patient derived xenograft AML cells. In vivo, 20D9‑ADC treatment led to a significant tumor reduction and even durable complete remission in AML xenograft models. Further, 20D9‑ADC demonstrated no severe hematotoxicity in in vitro colony formation assays using concentrations that were cytotoxic in AML cell line treatment. The combination of 20D9-ADC with the TKI midostaurin showed strong synergy in vitro and in vivo, leading to reduction of aggressive AML cells below the detection limit. Our data indicate that targeting FLT3 with an advanced new-generation ADC is a promising and potent antileukemic strategy, especially when combined with FLT3-TKI in FLT3‑ITD positive AML.

A heterotypic assembly mechanism regulates CHIP E3 ligase activity

Das, Aniruddha; Thapa, Pankaj; Santiago, Ulises; Shanmugam, Nilesh; Banasiak, Katarzyna; Dąbrowska, Katarzyna; Nolte, Hendrik; Szulc, Natalia A; Gathungu, Rose M; Cysewski, Dominik; Krüger, Marcus; Dadlez, Michał; Nowotny, Marcin; Camacho, Carlos J; Hoppe, Thorsten; Pokrzywa, Wojciech
The EMBO Journal.
Aug 2022
10.15252/embj.2021109566
CHIP (C‐terminus of Hsc70‐interacting protein) and its worm ortholog CHN‐1 are E3 ubiquitin ligases that link the chaperone system with the ubiquitin‐proteasome system (UPS). CHN‐1 can cooperate with UFD‐2, another E3 ligase, to accelerate ubiquitin chain formation; however, the basis for the high processivity of this E3s set has remained obscure. 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. However, HSP70/HSP‐1 chaperone outcompetes UFD‐2 for CHN‐1 binding, thereby promoting a shift to the autoinhibited CHN‐1 state by acting on a conserved residue in its U‐box domain. The interaction with UFD‐2 enables CHN‐1 to efficiently ubiquitylate and regulate S‐adenosylhomocysteinase (AHCY‐1), a key enzyme in the S‐adenosylmethionine (SAM) regeneration cycle, which is essential for SAM‐dependent methylation. Our results define the molecular mechanism underlying the synergistic cooperation of CHN‐1 and UFD‐2 in substrate ubiquitylation.

IFx-Hu2.0 phase I first in human study for unresectable melanoma for an intralesional “in-situ vaccine” approach.

Markowitz, Joseph; Shamblott, Michael; Brohl, Andrew Scott; Sarnaik, Amod; Eroglu, Zeynep; Khushalani, Nikhil I.; Chen, Pei-Ling; De-Aquino, Deanryan B.; Sondak, Vernon K.; Tarhini, Ahmad A.; Kim, Youngchul; Pilon-Thomas, Shari
Jun 2022
10.1200/JCO.2022.40.16_suppl.e21542
e21542 Background: Many melanoma patients do not respond to anti-PD1 therapy due to lack of antigen specific responses. IFx-Hu2.0 (plasmid DNA encoding the streptococcal membrane protein, Emm55, contained within a cationic polymer) primes innate and antigen dependent responses in murine/equine melanoma models to produce an environment needed for checkpoint inhibitor efficacy. We describe the first in human study utilizing IFx-Hu2.0 in unresectable melanoma – NCT03655756. Methods: Melanoma patients (unresectable stage III/IV) had cutaneous lesions injected with IFx-Hu2.0 to test safety and feasibility. Patients were refractory to standard of care (anti-PD1, BRAF/MEK) or did not wish these treatments. 1-3 lesions (> 3 mm – 0.1 mg/0.2 mL) were injected, pre/post treatment biopsies obtained, and the primary endpoint of 5/6 patients without dose limiting toxicity (DLT) was assessed at 28 days. Retreatment was permitted. ≥2 lesions were needed: one for injection and uninjected lesion for biopsy. Tissue samples were analyzed for mRNA profiles, antigen responses (PEPperPRINT assay), and multiplex immunofluorescence (markers: CD3, CD8, FOXP3, PD1, PDL1, SOX10, DAPI). Results: The primary endpoint was met in 6 evaluable patients out of 7 enrolled. Observed toxicities included: G1-2 Injection site reactions – 5/7; G1 Bleeding – 1/7; G1-2 Pain – 2/7, G1 Lymphopenia – 1/7, G1 Pruritis – 1/7; with no ≥ G3 toxicities related to study drug observed. One G5 toxicity (Clostridium septicum infection 20 days post injection) was deemed unlikely related to study drug. 5/6 patients received 1 cycle prior to post-protocol immune-based therapy. One treatment naïve patient retreated once with IFx-Hu2.0 required no additional therapy > 9 months. Available paired tissue and plasma sampling revealed increased T cell infiltration into treated lesions, increase in IgM and IgG epitope recognition to melanoma associated antigens in the plasma (detected by PEPperPRINT assay), an increase in mRNA associated with innate immune responses in the injected lesion (CXCL13, LAG3, CXCL11, CXCL10, ICOS) and an adaptive immune response (IL-12, HLA-DRB5, WNT4, CD3D, Arg I) in uninjected lesions associated with downregulation of known melanoma antigens. Of 4 anti-PD1 refractory patients, three patients had clinical benefit to post-protocol retreatment with anti-PD1 based therapy (Stable Disease (SD) lasting > 2 years followed by surgical resection, Partial Response (PR) lasting > 9 months, PR subsequently surgical resected and rendered no evidence of disease). Conclusions: In this pilot study, intralesional IFx-Hu2.0 demonstrated a favorable safety profile. These data support encouraging immunological correlative responses and further study of IFx-Hu2.0 as a priming agent to enhance or restore sensitivity to immune checkpoint inhibitor therapy in melanoma. Clinical trial information: NCT03655756.

Generation and characterization of monoclonal antibodies that recognize human and murine supervillin protein isoforms

Smith, Tara C.; Saul, Richard G.; Barton, Elisabeth R.; Luna, Elizabeth J.
PLoS ONE.
Oct 2018
10.1371/journal.pone.0205910
Supervillin isoforms have been implicated in cell proliferation, actin filament-based motile processes, vesicle trafficking, and signal transduction. However, an understanding of the roles of these proteins in cancer metastasis and physiological processes has been limited by the difficulty of obtaining specific antibodies against these highly conserved membrane-associated proteins. To facilitate research into the biological functions of supervillin, monoclonal antibodies were generated against the bacterially expressed human supervillin N-terminus. Two chimeric monoclonal antibodies with rabbit Fc domains (clones 1E2/CPTC-SVIL-1; 4A8/CPTC-SVIL-2) and two mouse monoclonal antibodies (clones 5A8/CPTC-SVIL-3; 5G3/CPTC-SVIL-4) were characterized with respect to their binding sites, affinities, and for efficacy in immunoblotting, immunoprecipitation, immunofluorescence microscopy and immunohistochemical staining. Two antibodies (1E2, 5G3) recognize a sequence found only in primate supervillins, whereas the other two antibodies (4A8, 5A8) are specific for a more broadly conserved conformational epitope(s). All antibodies function in immunoblotting, immunoprecipitation and in immunofluorescence microscopy under the fixation conditions identified here. We also show that the 5A8 antibody works on immunohistological sections. These antibodies should provide useful tools for the study of mammalian supervillins.

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
10.1371/journal.pgen.1007622
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
10.1002/adma.201801632
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.

Reductionist Approach in Peptide-Based Nanotechnology

Gazit, Ehud
Annu. Rev. Biochem..
Jun 2018
10.1146/annurev-biochem-062917-012541
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.

A Trifunctional Linker for Purified 3D Assembled Peptide Structure Arrays

Mattes, Daniela S.; Rentschler, Simone; Foertsch, Tobias C.; Münch, Stephan W.; Loeffler, Felix F.; Nesterov-Mueller, Alexander; Bräse, Stefan; Breitling, Frank
Small Methods.
Feb 2018
10.1002/smtd.201700205
Microarrays are an important tool in modern research that allow the rapid screening of many different interactions simultaneously. Peptide arrays, which bear different peptides arranged in separate spots, permit high-throughput screening to investigate linear and cyclic binding sites. To study conformational or discontinuous binding sites, protein arrays are the major choice. However, the tremendous costs for the generation of high-density protein arrays of high purity restrict progress in protein research. Therefore, peptide-based arrays, which can mimic assembled peptide structures, have an enormous potential. Here, a method is presented to create such structures in the array format as an alternative to protein arrays. A trifunctional linker is developed with an azide, a protected alkyne, and a carboxyl group, which can react with two or three different peptides. Due to the spatial proximity, the peptides interact and can form an assembled peptide structure. As a proof of concept, assembled peptide structures are demonstrated on beads and on a polymer surface and the approach can be validated via matrix-assisted laser desorption/ionization spectrometry. Furthermore, a multistep transfer of peptide arrays is shown, generating purified assembled peptide structure arrays in high density.

Characterization of a sandwich ELISA for the quantification of all human periostin isoforms

Gadermaier, Elisabeth; Tesarz, Manfred; Suciu, Andreea Ana-Maria; Wallwitz, Jacqueline; Berg, Gabriela; Himmler, Gottfried
J Clin Lab Anal.
Feb 2018
10.1002/jcla.22252
Background Periostin (osteoblast-specific factor OSF-2) is a secreted protein occurring in seven known isoforms, and it is involved in a variety of biological processes in osteology, tissue repair, oncology, cardiovascular and respiratory systems or allergic manifestations. To analyze functional aspects of periostin, or the ability of periostin as potential biomarker in physiological and pathological conditions, there is the need for a precise, well-characterized assay that detects periostin in peripheral blood. Methods In this study the development of a sandwich ELISA using monoclonal and affinity-purified polyclonal anti-human periostin antibodies was described. Antibodies were characterized by mapping of linear epitopes with microarray technology, and by analyzing cross-reactive binding to human periostin isoforms with western blot. The assay was validated according to ICH/EMEA guidelines. Results The monoclonal coating antibody binds to a linear epitope conserved between the isoforms. The polyclonal detection antibody recognizes multiple conserved linear epitopes. Therefore, the periostin ELISA detects all known human periostin isoforms. The assay is optimized for human serum and plasma and covers a calibration range between 125 and 4000 pmol/L for isoform 1. Assay characteristics, such as precision (intra-assay: ≤3%, inter-assay: ≤6%), spike-recovery (83%-106%), dilution linearity (95%-126%), as well as sample stability meet the standards of acceptance. Periostin levels of apparently healthy individuals are 864±269 pmol/L (serum) and 817±170 pmol/L (plasma) respectively. Conclusion This ELISA is a reliable and accurate tool for determination of all currently known periostin isoforms in human healthy and diseased samples.

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