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

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Systematic analysis of the RGS2 degron reveals characteristics of substrate recognition by the F-box protein FBXO44

McNabb, Harrison J.; Cho, Eugene; Pitman, Mary; Rushton, Phillip S.; Mobley, David; Sjögren, Benita
Journal of Biological Chemistry.
Nov 2025
10.1016/j.jbc.2025.110757
Regulator of G protein signaling 2 (RGS2) negatively modulates signaling downstream of G protein–coupled receptors by accelerating GTP hydrolysis at Gα subunits of heterotrimeric G proteins. Decreased RGS2 levels are implicated in numerous diseases, including cardiovascular disease and asthma. Thus, identifying selective means of enhancing RGS2 protein levels would be a viable therapeutic strategy. RGS2 is rapidly degraded through the ubiquitin–proteasomal pathway, and we previously identified F-box only protein 44 (FBXO44) as the substrate recognition component of the E3 ligase responsible for facilitating RGS2 degradation. As such, the RGS2–FBXO44 interaction is a potential target for pharmacological intervention. Detailed information on the FBXO44 recognition site (degron) in RGS2 will aid in structure-based small-molecule inhibitor design, as well as in identifying additional FBXO44 targets, which would help predict possible side effects of targeting this interaction. Thus, the goal of this study was to dissect the molecular properties for FBXO44 binding of the RGS2 degron. We used a peptide array utilizing systematic residue substitution, combined with AlphaFold modeling and molecular dynamics simulations, to identify several amino acid changes that altered binding both positively and negatively. Finally, we experimentally confirmed our results in cells through coimmunoprecipitation and proteasomal inhibition, using full-length RGS2. Altogether, these results provide structural insights into RGS2–FBXO44 binding, which will aid in structure-guided drug discovery efforts. It also provides a framework for building a consensus recognition motif for FBXO44, which could aid in identifying more substrates for this understudied F-box protein.

Preclinical characterization of an active immunotherapy targeting calcitonin gene-related peptide

Boyd, Justin D.; Wang, Shixia; Lin, Hsiao-Wen; Hsieh, Yueh-Ting; Sun, Yu Shuang; Thibodeaux, Brett A.; Lu, Hanxin; Sahni, Jaya; Wiggins, Jonathan; Longo, Matthew S.; Brooks, Jeanne K.; Vroom, Madeline M.; Chang, Yi-Pin; Liu, Zhi; Ding, Shuang; Dodart, Jean-Cosme
Commun Med.
Apr 2025
10.1038/s43856-025-00870-2
Abstract **Background** The success of passive immunotherapies targeting Calcitonin gene-related peptide (CGRP) for managing migraine has prompted our efforts towards developing an active immunotherapy that induces the production of endogenous antibodies against CGRP. Achieving efficacious antibody titers via immunization could provide a more convenient and cost-effective treatment alternative to anti-CGRP monoclonal antibody (mAb) therapies. However, immunization against endogenous CGRP faces multiple challenges such as breaking immune tolerance, inducing sufficient antibody titers, and avoiding immune response-associated toxicity. **Methods** Synthetic peptide immunogens formulated in adjuvants were delivered intramuscularly. Serum samples were collected post immunization and used to measure antibody titers as well as for the isolation of antibodies specific to CGRP. Antibodies were characterized for their binding affinities and specificities. The capsaicin-induced increase in dermal blood flow model was used in rats for the assessment of the pharmacodynamic effect of immunization. **Results** Here we demonstrate that a peptide-based active immunotherapy designed to induce antibodies against CGRP promotes robust antibody titers across preclinical species. Characterization of the immune response strongly suggests that this peptide immunogen primarily stimulates a humoral response and only induced CGRP-specific antibodies. Antibodies produced by immunization are primarily IgG1 and demonstrate binding and activity potencies similar to marketed monoclonal antibodies against CGRP. Finally, immunization demonstrates in vivo efficacy in a rat pharmacodynamic model. **Conclusion** Our results strongly suggest that a peptide-based active immunotherapy against CGRP could provide an affordable and convenient therapeutic for the prevention of migraine.

A tumor-binding antibody with cross-reactivity to viral antigens

Campa, Michael J.; Gottlin, Elizabeth B.; Wiehe, Kevin; Patz, Edward F.
Cancer Immunol Immunother.
Feb 2025
10.1007/s00262-025-03975-8
**Background** We previously identified in non-small cell lung cancer (NSCLC) patients an autoantibody to complement factor H (CFH) that is associated with non-metastatic disease and longer time to progression in patients with stage I disease. A recombinant human antibody, GT103, was cloned from single B cells isolated from patients with the autoantibody. GT103 inhibits tumor growth and establishes an antitumor microenvironment. The anti-CFH autoantibody and GT103 recognize the epitope PIDNGDIT within the SCR19 domain of CFH. Here, we asked if this autoantibody could have originally arisen as a humoral response to a similar epitope in a viral protein from a prior infection. **Methods** Homologous viral peptides with high sequence identity to the core PIDNGDIT epitope sequence were identified and synthesized. NSCLC patient plasma containing anti-CFH autoantibodies were assayed by ELISA against these peptides. GT103 was assayed on a 4345-peptide pathogen microarray. **Results** Epitopes similar to the GT103 epitope are present in several viruses, including human metapneumovirus-1 (HMPV-1) that contains a sequence within attachment glycoprotein G that differs by one amino acid. Anti-CFH autoantibodies in NSCLC patient plasma weakly bound to an HMPV-1 peptide containing the epitope. GT103 cross-reacted with multiple viral epitopes on a peptide microarray, with the top hits being peptides in the human endogenous retrovirus-K polymerase (HERV-K pol) protein and measles hemagglutinin glycoprotein. GT103 bound the viral HMPV-1, HERV-K pol, and measles epitope peptides but with lower affinity compared to the GT103 epitope peptide. **Conclusion** These findings suggest that memory B cells against a viral target could have affinity matured to produce an antibody that recognizes a similar epitope on tumor cells and exhibits antitumor properties.

Anti-allodynic effect of intrathecal antibodies against macrophage-inducible C-type lectin in spinal nerve ligation model in rat

Kang, Dong Ho; Kim, Woong Mo; Bae, Hong Beom; Yang, Jihoon; Choi, Jeong Il
Heliyon.
Nov 2024
10.1016/j.heliyon.2024.e40694
*Introduction* Macrophage-inducible C-type lectin (Mincle) has emerged as a potential contributor to neuropathic pain induction and neuroinflammatory responses within the spinal cord. Moreover, evidence suggests a close association between toll-like receptor (TLR) and Mincle expression in myeloid cells. This study evaluated the effectiveness of Mincle antibodies in neuropathic pain and identified the epitope of these antibodies. In addition, the mode of interaction between Mincle and TLR inhibition was explored using isobolographic analysis. *Methods* Three different Mincle antibodies and a specific TLR4 inhibitor (TAK-242) were intrathecally administered, and mechanical allodynia was evaluated using the von Frey test in a rat model of spinal nerve ligation (SNL). Isobolographic analysis was conducted on the effect of combination of TAK-242 and Mincle Ab. Microarray analysis examined the specific region of Mincle targeted by the antibodies. *Results* All Mincle antibodies and TAK-242 significantly alleviated mechanical allodynia in a dose-dependent manner. However, the maximal possible effects (MPE) produced by the antibodies ranged widely from 37.1% to 91.8%, comparable to that of TAK-242 (88.7%). The combination of TAK-242 and the antibody with the highest MPE resulted in an additive interaction for their anti-allodynic effects. Epitope mapping revealed that each antibody targeted the extracellular domain, with epitope lengths ranging from 5 to 15 amino acids. *Conclusions* The current study demonstrates the anti-allodynic effect of Mincle antibodies and additive interaction with TLR4 inhibition in spinal nerve ligation model, suggesting the potential of blocking of Mincle signaling with its antibodies as a novel treatment strategy for neuropathic pain.

Discovery of a novel highly specific, fully human PSCA antibody and its application as an antibody-drug conjugate in prostate cancer

Chu, Xiaojie; Shin, Seungmin; Baek, Du-San; Zhang, Liyong; Conard, Alex; Shi, Megan; Kim, Ye-Jin; Adams, Cynthia; Hines, Maggie; Liu, Xianglei; Chen, Chuan; Sun, Zehua; Jelev, Dontcho V.; Mellors, John W.; Dimitrov, Dimiter S.; Li, Wei
mAbs.
Aug 2024
10.1080/19420862.2024.2387240
Prostate stem cell antigen (PSCA) is expressed in all stages of prostate cancer, including in advanced androgen-independent tumors and bone metastasis. PSCA may associate with prostate carcinogenesis and lineage plasticity in prostate cancer. PSCA is also a promising theranostic marker for a variety of other solid tumors, including pancreatic adenocarcinoma and renal cell carcinoma. Here, we identified a novel fully human PSCA antibody using phage display methodology. The structure-based affinity maturation yielded a high-affinity binder, F12, which is highly specific and does not bind to 6,000 human membrane proteins based on a membrane proteome array assay. F12 targets PSCA amino acids 63–69 as tested by the peptide scanning microarray, and it cross-reacts with the murine PSCA. IgG1 F12 efficiently internalizes into PSCA-expressing tumor cells. The antimitotic reagent monomethyl auristatin E (MMAE)-conjugated IgG1 F12 (ADC, F12-MMAE) exhibits dose-dependent efficacy and specificity in a human prostate cancer PC-3-PSCA xenograft NSG mouse model. This is a first reported ADC based on a fully human PSCA antibody and MMAE that is characterized in a xenograft murine model, which warrants further optimizations and investigations in additional preclinical tumor models, including prostate and other solid tumors.

Antigen-Heterologous Vaccination Regimen Triggers Alternate Antibody Targeting in SARS-CoV-2-DNA-Vaccinated Mice

Frische, Anders; Krogfelt, Karen Angeliki; Fomsgaard, Anders; Lassaunière, Ria
Vaccines.
Feb 2024
10.3390/vaccines12030218
An in-depth analysis of antibody epitopes following vaccination with different regimens provides important insight for developing future vaccine strategies. B-cell epitopes conserved across virus variants may be ideal targets for vaccine-induced antibodies and therapeutic drugs. However, challenges lie in identifying these key antigenic regions, and directing the immune system to target them. We previously evaluated the immunogenicity of two candidate DNA vaccines encoding the unmodified spike protein of either the SARS-CoV-2 Index strain or the Beta variant of concern (VOC). As a follow-on study, we characterized here the antibody binding profiles of three groups of mice immunized with either the DNA vaccine encoding the SARS-CoV-2 Index strain spike protein only, the Beta VOC spike protein only, or a combination of both as an antigen-heterologous prime-boost regimen. The latter induced an antibody response targeting overlapping regions that were observed for the individual vaccines but with additional high levels of antibody directed against epitopes in the SD2 region and the HR2 region. These heterologous-vaccinated animals displayed improved neutralization breadth. We believe that a broad-focused vaccine regimen increases neutralization breadth, and that the in-depth analysis of B-cell epitope targeting used in this study can be applied in future vaccine research.

Influenza‐associated thrombotic thrombocytopenic purpura: A report of two cases and a brief review of the literature

Onkarappa Mangala, Yashvin; Sweeney, Joseph D.
Vox Sanguinis.
Nov 2021
10.1111/vox.13227
Background and Objectives Thrombotic thrombocytopenic purpura (TTP) is often preceded by a recent history of an acute infection and influenza is the most implicated virus. Materials and Methods We identified two cases of TTP, which were preceded by influenza between 2010 and 2021. In one patient, we epitope mapped the binding specificity of antibodies using an overlapping peptide approach of the stalk protein of Influenza B and the cysteine-rich spacer domain (CRSD) of ADAMTS13. A literature search was performed for reports of influenza-associated TTP over the period 1980–2021. Results Two patients were identified in which TTP was preceded by influenza, one Influenza A and the other Influenza B. Epitope mapping of the latter’s plasma identified target epitopes in both the stalk protein of Influenza B and CRSD of ADAMTS13. The literature review revealed only seven case reports, all but one from Europe or Asia and associated with Influenza A. Severe ADAMTS13 deficiency was demonstrated in only four cases. Conclusion We report the first small case series of influenza-associated TTP. Moreover, it is the first case implicating Influenza B and a mechanism favouring polyclonal B-cell proliferation rather than molecular mimicry as the stimulus to form anti-ADAMTS13 auto-antibodies is suggested.

The Potential Role of Human NME1 in Neuronal Differentiation of Porcine Mesenchymal Stem Cells: Application of NB-hNME1 as a Human NME1 Suppressor

Cho, Jin Hyoung; Ju, Won Seok; Seo, Sang Young; Kim, Bo Hyun; Kim, Ji-Su; Kim, Jong-Geol; Park, Soon Ju; Choo, Young-Kug
Int J Mol Sci.
Nov 2021
10.3390/ijms222212194
This study aimed to investigate the effects of the human macrophage (MP) secretome in cellular xenograft rejection. The role of human nucleoside diphosphate kinase A (hNME1), from the secretome of MPs involved in the neuronal differentiation of miniature pig adipose tissue-derived mesenchymal stem cells (mp AD-MSCs), was evaluated by proteomic analysis. Herein, we first demonstrate that hNME1 strongly binds to porcine ST8 alpha-N-acetyl-neuraminide alpha-2,8-sialyltransferase 1 (pST8SIA1), which is a ganglioside GD3 synthase. When hNME1 binds with pST8SIA1, it induces degradation of pST8SIA1 in mp AD-MSCs, thereby inhibiting the expression of ganglioside GD3 followed by decreased neuronal differentiation of mp AD-MSCs. Therefore, we produced nanobodies (NBs) named NB-hNME1 that bind to hNME1 specifically, and the inhibitory effect of NB-hNME1 was evaluated for blocking the binding between hNME1 and pST8SIA1. Consequently, NB-hNME1 effectively blocked the binding of hNME1 to pST8SIA1, thereby recovering the expression of ganglioside GD3 and neuronal differentiation of mp AD-MSCs. Our findings suggest that mp AD-MSCs could be a potential candidate for use as an additive, such as an immunosuppressant, in stem cell transplantation.

Human Antibody Domains and Fragments Targeting Neutrophil Elastase as Candidate Therapeutics for Cancer and Inflammation-Related Diseases

Chu, Xiaojie; Sun, Zehua; Baek, Du-San; Li, Wei; Mellors, John W.; Shapiro, Steven D.; Dimitrov, Dimiter S.
Int J Mol Sci.
Oct 2021
10.3390/ijms222011136
Neutrophil elastase (NE) is a serine protease released during neutrophil maturation. High levels of NE are related to lung tissue damage and poor prognosis in cancer; thus, NE is a potential target for therapeutic immunotherapy for multiple lung diseases and cancers. Here, we isolate and characterize two high-affinity, specific, and noncompetitive anti-NE antibodies Fab 1C10 and VH 1D1.43 from two large phage-displayed human Fab and VH libraries. After fusion with human IgG1 Fc, both of them (VH-Fc 1D1.43 and IgG1 1C10) inhibit NE enzymatic activity with VH-Fc 1D1.43 showing comparable inhibitory effects to that of the small molecule NE inhibitor SPCK and IgG1 1C10 exhibiting even higher (2.6-fold) activity than SPCK. Their epitopes, as mapped by peptide arrays combined with structural modeling, indicate different mechanisms for blocking NE activity. Both VH-Fc and IgG1 antibodies block NE uptake by cancer cells and fibroblast differentiation. VH-Fc 1D1.43 and IgG1 1C10 are promising for the antibody-based immunotherapy of cancer and inflammatory diseases.

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
10.1007/s12192-021-01229-x
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.

Non-invasive immunoPET imaging of PD-L1 using anti-PD-L1-B11 in breast cancer and melanoma tumor model

Bansal, Aditya; Pandey, Mukesh K.; Barham, Whitney; Liu, Xin; Harrington, Susan M.; Lucien, Fabrice; Dong, Haidong; Park, Sean S.; DeGrado, Timothy R.
Nuclear Medicine and Biology.
May 2021
10.1016/j.nucmedbio.2021.05.004
Introduction Immunotherapy targeting PD-1/PD-L1 immune checkpoint inhibition (ICI) is efficacious in various solid and hematologic malignancies. However, the response rate to PD-1/PD-L1 therapy is only 15–35%. To obtain optimal clinical response to ICI therapies, a reliable assessment of tumor PD-L1 expression is needed to select appropriate patients, and a non-invasive imaging-based assessment of PD-L1 expression is critically needed. Although radiolabeled PET probes based on PD-L1 targeted therapeutic antibodies (e.g. atezolizumab) have shown encouraging results, there is concern that residual therapeutic antibody may compete for binding with the radiotracer thereby compromising imaging studies that follow treatment. Methods and results In this study, we used novel anti-PD-L1-B11 clone antibody known to bind to a different epitope of PD-L1 than the therapeutic antibodies to avoid potential saturation effects. The anti-PD-L1-B11 clone was radiolabeled with zirconium-89 and evaluated to detect PD-L1 expression in various in vitro and in vivo cancer model systems in comparison with [89Zr]Zr-DFO-NCS-atezolizumab. In vitro binding parameters of anti-PD-L1-B11 were like those of atezolizumab. [89Zr]Zr-DFO-NCS-anti-PD-L1-B11 clone showed favorable properties to [89Zr]Zr-DFO-NCS-atezolizumab in an in vivo breast cancer tumor model system with higher uptake in PD-L1 expressing tumors. Conclusion Our data demonstrates that [89Zr]Zr-DFO-NCS-anti-PD-L1-B11 exhibits excellent imaging properties for the assessment PD-L1 expression. The independent binding site of anti-PD-L1-B11 relative to therapeutic anti-PD-L1 antibodies may be advantageous for anti-PD-L1 therapy monitoring.

Analysis of chronic inflammatory lesions of the colon for BMMF Rep antigen expression and CD68 macrophage interactions

Bund, Timo; Nikitina, Ekaterina; Chakraborty, Deblina; Ernst, Claudia; Gunst, Karin; Boneva, Boyana; Tessmer, Claudia; Volk, Nadine; Brobeil, Alexander; Weber, Achim; Heikenwalder, Mathias; Zur Hausen, Harald; de Villiers, Ethel-Michele
Proc Natl Acad Sci U S A.
Mar 2021
10.1073/pnas.2025830118
Consumption of Eurasian bovine meat and milk has been associated with cancer development, in particular with colorectal cancer (CRC). In addition, zoonotic infectious agents from bovine products were proposed to cause colon cancer (zur Hausen et al., 2009). Bovine meat and milk factors (BMMF) are small episomal DNA molecules frequently isolated from bovine sera and milk products, and recently, also from colon cancer (de Villiers et al., 2019). BMMF are bioactive in human cells and were proposed to induce chronic inflammation in precancerous tissue leading to increased radical formation: for example, reactive oxygen and reactive nitrogen species and elevated levels of DNA mutations in replicating cells, such as cancer progenitor cells (zur Hausen et al., 2018). Mouse monoclonal antibodies against the replication (Rep) protein of H1MSB.1 (BMMF1) were used to analyze BMMF presence in different cohorts of CRC peritumor and tumor tissues and cancer-free individuals by immunohistochemistry and Western blot. BMMF DNA was isolated by laser microdissection from immunohistochemistry-positive tissue regions. We found BMMF Rep protein present specifically in close vicinity of CD68+ macrophages in the interstitial lamina propria adjacent to CRC tissues, suggesting the presence of local chronic inflammation. BMMF1 (modified H1MSB.1) DNA was isolated from the same tissue regions. Rep and CD68+ detection increased significantly in peritumor cancer tissues when compared to tissues of cancer-free individuals. This strengthens previous postulations that BMMF function as indirect carcinogens by inducing chronic inflammation and DNA damage in replicating cells, which represent progress to progenitor cells for adenoma (polyps) formation and cancer.

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