The l-isoaspartate modification within protein fragments in the aging lens can promote protein aggregation.

Transparency in the lens is accomplished by the dense packing and short-range order interactions of the crystallin proteins in fiber cells lacking organelles. These features are accompanied by a lack of protein turnover, leaving lens proteins susceptible to a number of damaging modifications and aggregation. The loss of lens transparency is attributed in part to such aggregation during aging. Among the damaging post-translational modifications that accumulate in long-lived proteins, isomerization at aspartate residues has been shown to be extensive throughout the crystallins. In this study of the human lens, we localize the accumulation of l-isoaspartate within water-soluble protein extracts primarily to crystallin peptides in high-molecular weight aggregates and show with MS that these peptides are from a variety of crystallins. To investigate the consequences of aspartate isomerization, we investigated two αA crystallin peptides 52LFRTVLDSGISEVR65 and 89VQDDFVEIH98, identified within this study, with the l-isoaspartate modification introduced at Asp58 and Asp91, respectively. Importantly, whereas both peptides modestly increase protein precipitation, the native 52LFRTVLDSGISEVR65 peptide shows higher aggregation propensity. In contrast, the introduction of l-isoaspartate within a previously identified anti-chaperone peptide from water-insoluble aggregates, αA crystallin 66SDRDKFVIFL(isoAsp)VKHF80, results in enhanced amyloid formation in vitro The modification of this peptide also increases aggregation of the lens chaperone αB crystallin. These findings may represent multiple pathways within the lens wherein the isomerization of aspartate residues in crystallin peptides differentially results in peptides associating with water-soluble or water-insoluble aggregates. Here the eye lens serves as a model for the cleavage and modification of long-lived proteins within other aging tissues.

Combining high-throughput MALDI-TOF mass spectrometry and isoelectric focusing gel electrophoresis for virtual 2D gel-based proteomics.

The virtual two-dimensional gel electrophoresis/mass spectrometry (virtual 2D gel/MS) technology combines the premier, high-resolution capabilities of 2D gel electrophoresis with the sensitivity and high mass accuracy of mass spectrometry (MS). Intact proteins separated by isoelectric focusing (IEF) gel electrophoresis are imaged from immobilized pH gradient (IPG) polyacrylamide gels (the first dimension of classic 2D-PAGE) by matrix-assisted laser desorption/ionization (MALDI) MS. Obtaining accurate intact masses from sub-picomole-level proteins embedded in 2D-PAGE gels or in IPG strips is desirable to elucidate how the protein of one spot identified as protein 'A' on a 2D gel differs from the protein of another spot identified as the same protein, whenever tryptic peptide maps fail to resolve the issue. This task, however, has been extremely challenging. Virtual 2D gel/MS provides access to these intact masses. Modifications to our matrix deposition procedure improve the reliability with which IPG gels can be prepared; the new procedure is described. Development of this MALDI MS imaging (MSI) method for high-throughput MS with integrated 'top-down' MS to elucidate protein isoforms from complex biological samples is described and it is demonstrated that a 4-cm IPG gel segment can now be imaged in approximately 5min. Gel-wide chemical and enzymatic methods with further interrogation by MALDI MS/MS provide identifications, sequence-related information, and post-translational/transcriptional modification information. The MSI-based virtual 2D gel/MS platform may potentially link the benefits of 'top-down' and 'bottom-up' proteomics.

Development and application of a quantitative multiplexed small GTPase activity assay using targeted proteomics.

Small GTPases are a family of key signaling molecules that are ubiquitously expressed in various types of cells. Their activity is often analyzed by western blot, which is limited by its multiplexing capability, the quality of isoform-specific antibodies, and the accuracy of quantification. To overcome these issues, a quantitative multiplexed small GTPase activity assay has been developed. Using four different binding domains, this assay allows the binding of up to 12 active small GTPase isoforms simultaneously in a single experiment. To accurately quantify the closely related small GTPase isoforms, a targeted proteomic approach, i.e., selected/multiple reaction monitoring, was developed, and its functionality and reproducibility were validated. This assay was successfully applied to human platelets and revealed time-resolved coactivation of multiple small GTPase isoforms in response to agonists and differential activation of these isoforms in response to inhibitor treatment. This widely applicable approach can be used for signaling pathway studies and inhibitor screening in many cellular systems.

The Longitudinal Analysis of Convergent Antibody VDJ Regions in SARS-CoV-2-Positive Patients Using RNA-Seq.

Severe acute respiratory syndrome-related coronavirus-2 (SARS-CoV-2) is an ongoing pandemic that continues to evolve and reinfect individuals. To understand the convergent antibody responses that evolved over the course of the pandemic, we evaluated the immunoglobulin repertoire of individuals infected by different SARS-CoV-2 variants for similarity between patients. We utilized four public RNA-seq data sets collected between March 2020 and March 2022 from the Gene Expression Omnibus (GEO) in our longitudinal analysis. This covered individuals infected with Alpha and Omicron variants. In total, from 269 SARS-CoV-2-positive patients and 26 negative patients, 629,133 immunoglobulin heavy-chain variable region V(D)J sequences were reconstructed from sequencing data. We grouped samples based on the SARS-CoV-2 variant type and/or the time they were collected from patients. Our comparison of patients within each SARS-CoV-2-positive group found 1011 common V(D)Js (same V gene, J gene and CDR3 amino acid sequence) shared by more than one patient and no common V(D)Js in the noninfected group. Taking convergence into account, we clustered based on similar CDR3 sequence and identified 129 convergent clusters from the SARS-CoV-2-positive groups. Within the top 15 clusters, 4 contain known anti-SARS-CoV-2 immunoglobulin sequences with 1 cluster confirmed to cross-neutralize variants from Alpha to Omicron. In our analysis of longitudinal groups that include Alpha and Omicron variants, we find that 2.7% of the common CDR3s found within groups were also present in more than one group. Our analysis reveals common and convergent antibodies, which include anti-SARS-CoV-2 antibodies, in patient groups over various stages of the pandemic.

Sulfonyl fluoride-based prosthetic compounds as potential 18F labelling agents.

Nucleophilic incorporation of [(18)F]F(-) under aqueous conditions holds several advantages in radiopharmaceutical development, especially with the advent of complex biological pharmacophores. Sulfonyl fluorides can be prepared in water at room temperature, yet they have not been assayed as a potential means to (18)F-labelled biomarkers for PET chemistry. We developed a general route to prepare bifunctional 4-formyl-, 3-formyl-, 4-maleimido- and 4-oxylalkynl-arylsulfonyl [(18)F]fluorides from their sulfonyl chloride analogues in 1:1 mixtures of acetonitrile, THF, or tBuOH and Cs[(18)F]F/Cs(2)CO(3(aq.)) in a reaction time of 15 min at room temperature. With the exception of 4-N-maleimide-benzenesulfonyl fluoride (3), pyridine could be used to simplify radiotracer purification by selectively degrading the precursor without significantly affecting observed yields. The addition of pyridine at the start of [(18)F]fluorination (1:1:0.8 tBuOH/Cs(2)CO(3(aq.))/pyridine) did not negatively affect yields of 3-formyl-2,4,6-trimethylbenzenesulfonyl [(18)F]fluoride (2) and dramatically improved the yields of 4-(prop-2-ynyloxy)benzenesulfonyl [(18)F]fluoride (4). The N-arylsulfonyl-4-dimethylaminopyridinium derivative of 4 (14) can be prepared and incorporates (18)F efficiently in solutions of 100 % aqueous Cs(2)CO(3) (10 mg mL(-1)). As proof-of-principle, [(18)F]2 was synthesised in a preparative fashion [88(±8) % decay corrected (n=6) from start-of-synthesis] and used to radioactively label an oxyamino-modified bombesin(6-14) analogue [35(±6) % decay corrected (n=4) from start-of-synthesis]. Total preparation time was 105-109 min from start-of-synthesis. Although the (18)F-peptide exhibited evidence of proteolytic defluorination and modification, our study is the first step in developing an aqueous, room temperature (18)F labelling strategy.

Talimogene laherparepvec upregulates immune-cell populations in non-injected lesions: findings from a phase II, multicenter, open-label study in patients with stage IIIB-IVM1c melanoma.

BACKGROUND: Talimogene laherparepvec (T-VEC), an oncolytic virus, was designed to selectively replicate in and lyse tumor cells, releasing tumor-derived antigen to stimulate a tumor-specific immune response. METHODS: In this phase II study in patients with unresectable stage IIIB-IV melanoma, we evaluated non-injected lesions to establish whether baseline or change in intratumoral CD8+ T-cell density (determined using immunohistochemistry) correlated with T-VEC clinical response. RESULTS: Of 112 enrolled patients, 111 received ≥1 dose of T-VEC. After a median follow-up of 108.0 weeks, objective/complete response rates were 28%/14% in the overall population and 32%/18% in patients with stage IIIB-IVM1a disease. No unexpected toxicity occurred. Baseline and week 6 change from baseline CD8+ T-cell density results were available for 91 and 65 patients, respectively. Neither baseline nor change in CD8+ T-cell density correlated with objective response rate, changes in tumor burden, duration of response or durable response rate. However, a 2.4-fold median increase in CD8+ T-cell density in non-injected lesions from baseline to week 6 was observed. In exploratory analyses, multiparameter immunofluorescence showed that after treatment there was an increase in the proportion of infiltrating CD8+ T-cells expressing granzyme B and checkpoint markers (programmed death-1, programmed death-ligand 1 (PD-L1) and cytotoxic T-lymphocyte antigen-4) in non-injected lesions, together with an increase in helper T-cells. Consistent with T-cell infiltrate, we observed an increase in the adaptive resistance marker PD-L1 in non-injected lesions. CONCLUSIONS: This study indicates that T-VEC induces systemic immune activity and alters the tumor microenvironment in a way that will likely enhance the effects of other immunotherapy agents in combination therapy. TRIAL REGISTRATION NUMBER: NCT02366195.

Time-Dependent Measurement of Nrf2-Regulated Antioxidant Response to Ionizing Radiation Toward Identifying Potential Protein Biomarkers for Acute Radiation Injury.

PURPOSE: Potential acute exposure to ionizing radiation in nuclear or radiological accidents presents complex mass casualty scenarios that demand prompt triage and treatment decisions. Due to delayed symptoms and varied response of radiation victims, there is an urgent need to develop robust biomarkers to assess the extent of injuries in individuals. EXPERIMENTAL DESIGN: The transcription factor Nrf2 is the master of redox homeostasis and there is transcriptional evidence of Nrf2-dependent antioxidant response activation upon radiation. The biomarker potential of Nrf2-dependent downstream target enzymes is investigated by measuring their response in bone marrow extracted from C57Bl/6 and C3H mice of both genders for up to 4 days following 6 Gy total body irradiation using targeted MS. RESULTS: Overall, C57Bl/6 mice have a stronger proteomic response than C3H mice. In both strains, male mice have more occurrences of upregulation in antioxidant enzymes than female mice. For C57Bl/6 male mice, three proteins show elevated abundances after radiation exposure: catalase, superoxide dismutase 1, and heme oxygenase 1. Across both strains and genders, glutathione S-transferase Mu 1 is consistently decreased. CONCLUSIONS AND CLINICAL RELEVANCE: This study provides the basis for future development of organ-specific protein biomarkers used in diagnostic blood test for radiation injury.

Biodistribution, shedding, and transmissibility of the oncolytic virus talimogene laherparepvec in patients with melanoma.

BACKGROUND: Talimogene laherparepvec (T-VEC) is an intralesionally delivered, modified herpes simplex virus type-1 oncolytic immunotherapy. The biodistribution, shedding, and potential transmission of T-VEC was systematically evaluated during and after completion of therapy in adults with advanced melanoma. METHODS: In this phase 2, single-arm, open-label study, T-VEC was administered into injectable lesions initially at 106 plaque-forming units (PFU)/mL, 108 PFU/mL 21 days later, and 108 PFU/mL every 14 (±3) days thereafter. Injected lesions were covered with occlusive dressings for ≥1 week. Blood, urine, and swabs from exterior of occlusive dressings, surface of injected lesions, oral mucosa, anogenital area, and suspected herpetic lesions were collected throughout the study. Detectable T-VEC DNA was determined for each sample type; infectivity was determined for all swabs with detectable T-VEC DNA. FINDINGS: Sixty patients received ≥1 dose of T-VEC. During cycles 1-4, T-VEC DNA was detected in blood (98·3% of patients, 36·7% of samples), urine (31·7% of patients, 3·0% of samples) and swabs from injected lesions (100% of patients, 57·6% of samples), exterior of dressings (80% of patients,19·5% of samples), oral mucosa (8·3% of patients, 2·5% of samples), and anogenital area (8·0% of patients, 1·1% of samples). During the safety follow-up period, T-VEC DNA was only detected on swabs from injected lesions (14% of patients, 5.8% of samples). T-VEC DNA was detected in 4/37 swabs (3/19 patients) of suspected herpetic lesions. Among all samples, only those from the surface of injected lesions tested positive for infectivity (8/740 [1·1%]). Three close contacts reported signs and symptoms of suspected herpetic origin; however, no lesions had detectable T-VEC DNA. INTERPRETATION: Using current guidelines, T-VEC can be administered safely to patients with advanced melanoma and is unlikely to be transmitted to close contacts with appropriate use of occlusive dressings. FUND: This study was funded by Amgen Inc.: ClinicalTrials.gov, NCT02014441.