SARS-CoV-2 variants evolve convergent strategies to remodel the host response.

SARS-CoV-2 variants of concern (VOCs) emerged during the COVID-19 pandemic. Here, we used unbiased systems approaches to study the host-selective forces driving VOC evolution. We discovered that VOCs evolved convergent strategies to remodel the host by modulating viral RNA and protein levels, altering viral and host protein phosphorylation, and rewiring virus-host protein-protein interactions. Integrative computational analyses revealed that although Alpha, Beta, Gamma, and Delta ultimately converged to suppress interferon-stimulated genes (ISGs), Omicron BA.1 did not. ISG suppression correlated with the expression of viral innate immune antagonist proteins, including Orf6, N, and Orf9b, which we mapped to specific mutations. Later Omicron subvariants BA.4 and BA.5 more potently suppressed innate immunity than early subvariant BA.1, which correlated with Orf6 levels, although muted in BA.4 by a mutation that disrupts the Orf6-nuclear pore interaction. Our findings suggest that SARS-CoV-2 convergent evolution overcame human adaptive and innate immune barriers, laying the groundwork to tackle future pandemics.

A proximity proteomics pipeline with improved reproducibility and throughput.

Proximity labeling (PL) via biotinylation coupled with mass spectrometry (MS) captures spatial proteomes in cells. Large-scale processing requires a workflow minimizing hands-on time and enhancing quantitative reproducibility. We introduced a scalable PL pipeline integrating automated enrichment of biotinylated proteins in a 96-well plate format. Combining this with optimized quantitative MS based on data-independent acquisition (DIA), we increased sample throughput and improved protein identification and quantification reproducibility. We applied this pipeline to delineate subcellular proteomes across various compartments. Using the 5HT2A serotonin receptor as a model, we studied temporal changes of proximal interaction networks induced by receptor activation. In addition, we modified the pipeline for reduced sample input to accommodate CRISPR-based gene knockout, assessing dynamics of the 5HT2A network in response to perturbation of selected interactors. This PL approach is universally applicable to PL proteomics using biotinylation-based PL enzymes, enhancing throughput and reproducibility of standard protocols.

Probing Protein Structural Changes in Alzheimer's Disease via Quantitative Cross-linking Mass Spectrometry.

Alzheimer's disease (AD) is a progressive neurological disorder featuring abnormal protein aggregation in the brain, including the pathological hallmarks of amyloid plaques and hyperphosphorylated tau. Despite extensive research efforts, understanding the molecular intricacies driving AD development remains a formidable challenge. This study focuses on identifying key protein conformational changes associated with the progression of AD. To achieve this, we employed quantitative cross-linking mass spectrometry (XL-MS) to elucidate conformational changes in the protein networks in cerebrospinal fluid (CSF). By using isotopically labeled cross-linkers BS3d0 and BS3d4, we reveal a dynamic shift in protein interaction networks during AD progression. Our comprehensive analysis highlights distinct alterations in protein-protein interactions within mild cognitive impairment (MCI) states. This study accentuates the potential of cross-linked peptides as indicators of AD-related conformational changes, including previously unreported site-specific binding between α-1-antitrypsin (A1AT) and complement component 3 (CO3). Furthermore, this work enables detailed structural characterization of apolipoprotein E (ApoE) and reveals modifications within its helical domains, suggesting their involvement in MCI pathogenesis. The quantitative approach provides insights into site-specific interactions and changes in the abundance of cross-linked peptides, offering an improved understanding of the intricate protein-protein interactions underlying AD progression. These findings lay a foundation for the development of potential diagnostic or therapeutic strategies aimed at mitigating the negative impact of AD.

Inhibitor of glutamine metabolism V9302 promotes ROS-induced autophagic degradation of B7H3 to enhance antitumor immunity.

Despite the enormous successes of anti-PD-1/PD-L1 immunotherapy in multiple other cancer types, the overall response rates of breast cancer remain suboptimal. Therefore, exploring additional immune checkpoint molecules for potential cancer treatment is crucial. B7H3, a T-cell coinhibitory molecule, is specifically overexpressed in breast cancer compared with normal breast tissue and benign lesions, making it an attractive therapeutic target. However, the mechanism by which B7H3 contributes to the cancer phenotype is unclear. Here we show that the expression of B7H3 is negatively related to the number of CD8+ T cells in breast tumor sites. In addition, analysis of the differentially expressed B7H3 reveals that it is inversely correlated to autophagic flux both in breast cancer cell lines and clinical tumor tissues. Furthermore, block of autophagy by bafilomycin A1 (Baf A1) increases B7H3 levels and attenuates CD8+ T cell activation, while promotion of autophagy by V9302, a small-molecule inhibitor of glutamine metabolism, decreases B7H3 expression and enhances granzyme B (GzB) production of CD8+ T cells via regulation of reactive oxygen species (ROS) accumulation. We demonstrate that combined treatment with V9302 and anti-PD-1 monoclonal antibody (mAb) enhances antitumor immunity in syngeneic mouse models. Collectively, our findings unveil the beneficial effect of V9302 in boosting antitumor immune response in breast cancer and illustrate that anti-PD-1 together with V9302 treatment may provide synergistic effects in the treatment of patients insensitive to anti-PD-1 therapy.

In-depth Site-specific Analysis of N-glycoproteome in Human Cerebrospinal Fluid and Glycosylation Landscape Changes in Alzheimer's Disease.

As the body fluid that directly interchanges with the extracellular fluid of the central nervous system (CNS), cerebrospinal fluid (CSF) serves as a rich source for CNS-related disease biomarker discovery. Extensive proteome profiling has been conducted for CSF, but studies aimed at unraveling site-specific CSF N-glycoproteome are lacking. Initial efforts into site-specific N-glycoproteomics study in CSF yield limited coverage, hindering further experimental design of glycosylation-based disease biomarker discovery in CSF. In the present study, we have developed an N-glycoproteomic approach that combines enhanced N-glycopeptide sequential enrichment by hydrophilic interaction chromatography (HILIC) and boronic acid enrichment with electron transfer and higher-energy collision dissociation (EThcD) for large-scale intact N-glycopeptide analysis. The application of the developed approach to the analyses of human CSF samples enabled identifications of a total of 2893 intact N-glycopeptides from 511 N-glycosites and 285 N-glycoproteins. To our knowledge, this is the largest site-specific N-glycoproteome dataset reported for CSF to date. Such dataset provides molecular basis for a better understanding of the structure-function relationships of glycoproteins and their roles in CNS-related physiological and pathological processes. As accumulating evidence suggests that defects in glycosylation are involved in Alzheimer's disease (AD) pathogenesis, in the present study, a comparative in-depth N-glycoproteomic analysis was conducted for CSF samples from healthy control and AD patients, which yielded a comparable N-glycoproteome coverage but a distinct expression pattern for different categories of glycoforms, such as decreased fucosylation in AD CSF samples. Altered glycosylation patterns were detected for a number of N-glycoproteins including alpha-1-antichymotrypsin, ephrin-A3 and carnosinase CN1 etc., which serve as potentially interesting targets for further glycosylation-based AD study and may eventually lead to molecular elucidation of the role of glycosylation in AD progression.

Feasibility and reproducibility of semi-automated longitudinal strain analysis: a comparative study with conventional manual strain analysis.

BACKGROUND: Conventional approach to myocardial strain analysis relies on a software designed for the left ventricle (LV) which is complex and time-consuming and is not specific for right ventricular (RV) and left atrial (LA) assessment. This study compared this conventional manual approach to strain evaluation with a novel semi-automatic analysis of myocardial strain, which is also chamber-specific. METHODS: Two experienced observers used the AutoStrain software and manual QLab analysis to measure the LV, RV and LA strains in 152 healthy volunteers. Fifty cases were randomly selected for timing evaluation. RESULTS: No significant differences in LV global longitudinal strain (LVGLS) were observed between the two methods (-21.0% ± 2.5% vs. -20.8% ± 2.4%, p = 0.230). Conversely, RV longitudinal free wall strain (RVFWS) and LA longitudinal strain during the reservoir phase (LASr) measured by the semi-automatic software differed from the manual analysis (RVFWS: -26.4% ± 4.8% vs. -31.3% ± 5.8%, p < 0.001; LAS: 48.0% ± 10.0% vs. 37.6% ± 9.9%, p < 0.001). Bland-Altman analysis showed a mean error of 0.1%, 4.9%, and 10.5% for LVGLS, RVFWS, and LASr, respectively, with limits of agreement of -2.9,2.6%, -8.1,17.9%, and -12.3,33.3%, respectively. The semi-automatic method had a significantly shorter strain analysis time compared with the manual method. CONCLUSIONS: The novel semi-automatic strain analysis has the potential to improve efficiency in measurement of longitudinal myocardial strain. It shows good agreement with manual analysis for LV strain measurement.

Long Non-Coding RNA LINC00052 Targets miR-548p/Notch2/Pyk2 to Modulate Tumor Budding and Metastasis of Human Breast Cancer.

Abnormal expression of long non-coding RNAs (lncRNAs) is involved in many pathological processes of cancers. However, the role of lncRNA LINC00052 in breast cancer progression is still unclear. Here, LINC00052 expression was detected by in situ hybridization and quantitative real-time PCR assays. Cell Counting Kit-8, wound healing, and transwell assays were used to investigate changes in the proliferation, migration, and invasion of breast cancer cells. MiR-548p was found associated with LINC00052 or Notch2 by RNA pull-down, dual-luciferase reporter, and qRT-PCR assays. The effect of LINC00052 on lung metastasis was explored through in vivo experiments. High LINC00052 expression was observed in breast cancer tissues and cells. LINC00052 silencing inhibited the proliferation, migration, and invasion of MCF7 cells, and LINC00052 overexpression produced the opposite results. MiR-548p, a target gene of LINC00052, partially rescued the effects of LINC00052 on proliferation, migration, and invasion of MCF7. Notch2 was the target of miR-548p and LINC00052 could promote Notch2 expression. Moreover, the phosphorylation of proline-rich tyrosine kinase 2 (Pyk2), a downstream factor of Notch2, was increased by LINC00052, and a Pyk2 mutant could inhibit the cell migration and invasion induced by LINC00052 overexpression in MDA-MB-468 cells, which was similar to the function of the miR-548p mimic. We further demonstrated that LINC00052 exacerbated the metastases of breast cancer cells in vivo. Our research demonstrated that LINC00052 is highly expressed in breast cancer and promotes breast cancer proliferation, migration, and invasion via the miR-548p/Notch2/Pyk2 axis. LINC00052 could serve as a potential therapeutic target for breast cancer.

Sun-Cross Running Suture Combined with Transverse to Longitudinal Skin Closure to Correct Severe Inverted Nipple.

BACKGROUND: Inverted nipple deformity presents an unsatisfactory appearance that may induce an unpleasant sex life, but can also be associated with psychological discomfort and increased the functional problems, such as local irritation and inflammation. METHODS: Multiple techniques have been used to correct inverted nipples, but they mostly lead to different problems such as deficiency of the nerve or duct, recurrence of the inverted nipple, and hypopigmented scars in the areola. To minimize complications and maintain the stability of the reconstructed nipple, we presented a minimal incision technique that designed four 3-mm-sized horizontal microincisions, which ran a sun-cross through the periphery and the core of the nipple to push the nipple together, then a vertical suture ran longitudinal to close the transverse incision to stabilize the projection. RESULTS: This technique was performed in 71 patients classified as grade II or III of the inverted nipples, comprising 53 congenital cases and 18 patients with acquired deformity. Thirty-four patients had bilateral inverted nipples, and 37 patients had unilateral inverted nipple. During a mean follow-up period of 15 months, 70 corrected nipples remained raised without recurrence, and one nipple was found retracted at the outpatient clinic after 3 months. There were no serious complications associated with surgery regarding nipple necrosis, seven patients got temporary swelling, two patients got infected after touching water, three patients got extravasated blood, eight patients indicated that they touched scar under the nipple, and two patients reflected nipple dysesthesia. In the 15 months follow-up, the patients with Grade II nipple inversion maintained a nipple average height of 9.54 ± 0.95, and the patients with Grade III nipple inversion maintained a nipple average height of 9.19 ± 1.09, and 86.63% of patients were satisfied with their results. CONCLUSION: This is a simple, safe, effective and reliable technique that should be considered, providing sustained results over the long-term follow-up period with a high rate of stable eversion and low incidence of ischemia, necrosis, scarring and dysesthesia. The vertical scar of the transverse incision closure leads to an esthetic appearance without apparent scarring and minimizes the risk of an altered nipple sensation. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Nanovaccines Mediated Subcutis-to-Intestine Cascade for Improved Protection against Intestinal Infections.

Parenteral vaccines typically can prime systemic humoral immune response, but with limited effects on cellular and mucosal immunity. Here, a subcutis-to-intestine cascade for navigating nanovaccines to address this limitation is proposed. This five-step cascade includes lymph nodes targeting, uptaken by dendritic cells (DCs), cross-presentation of antigens, increasing CCR9 expression on DCs, and driving CD103+ DCs to mesenteric lymph nodes, in short, the LUCID cascade. Specifically, mesoporous silica nanoparticles are encapsulated with antigen and adjuvant toll-like receptor 9 agonist cytosine-phosphate-guanine oligodeoxynucleotides, and further coated by a lipid bilayer containing all-trans retinoic acid. The fabricated nanovaccines efficiently process the LUCID cascade to dramatically augment cellular and mucosal immune responses. Importantly, after being vaccinated with Salmonella enterica serovar Typhimurium antigen-loaded nanovaccine, the mice generate protective immunity against challenge of S. Typhimurium. These findings reveal the efficacy of nanovaccines mediated subcutis-to-intestine cascade in simultaneously activating cellular and mucosal immune responses against mucosal infections.

Enhanced resistance to soybean cyst nematode in transgenic soybean via host-induced silencing of vital Heterodera glycines genes.

Soybean cyst nematode (SCN, Heterodera glycines Ichinohe) is the most economically damaging pathogen affecting soybean production worldwide. Host-induced gene silencing provides a promising approach to confer resistance to plant parasitic nematodes. In the present study, we produced stable transgenic soybean plants individually harboring the inverted repeats of three essential H. glycines genes, Hg-rps23, Hg-snb1, and Hg-cpn1, and evaluated their resistance to SCN infection. Molecular characterization confirmed the stable integration of the hairpin double stranded (ds) RNA in host plants. Inoculation assays with SCN race 3 showed significant reduction of female index (FI, 11.84 ~ 17.47%) on the roots of T4 transgenic plants, with 73.29 ~ 81.90% reduction for the three RNA interference (RNAi) constructs, compared to non-transformed plants (NT, 65.43%). Enhanced resistance to SCN race 3 was further confirmed in subsequent generations (T5) of transgenic soybean. Moreover, when inoculated with SCN race 4 which was considered highly virulent to most of soybean germplasms and varieties, transgenic soybean plants also exhibited reduced FIs (9.96 ~ 23.67%) and increased resistance, relative to the NT plants (46.46%). Consistently, significant down-regulation in transcript levels of the Hg-rps23, Hg-snb1, Hg-cpn1 genes were observed in the nematodes feeding on the transgenic roots, suggesting a broad-spectrum resistance mediated by the host-mediated silencing of vital H. glycines genes. There were no significant differences in morphological traits between transgenic and NT soybean plants under conditions with negligible SCN infection. In summary, our results demonstrate the effectiveness of host-induced silencing of essential H. glycines genes to enhance broad-spectrum SCN resistance in stable transgenic soybean plants, without negative consequences on the agronomic performance.

Early detect left ventricular subclinical myocardial dysfunction in patients with systemic lupus erythematosus by a left ventricular pressure-strain loop.

OBJECTIVE: Noninvasive myocardial work (MW) is a new technology which is based on strain after considering the load influence on myocardial deformation. We aimed to investigate the feasibility of quantitatively assessing left ventricular myocardial work (LVMW) in patients with systemic lupus erythematosus (SLE) using a left ventricular pressure-strain loop (LVPSL). METHODS: 76 patients with SLE were included in the study (A), further divided into two subgroups according to the presence of lupus nephritis (LN). Global longitudinal strain (GLS), peak strain dispersion (PSD), global myocardial work index (GWI), global constructive work (GCW), global wasted work (GWW), and global work efficiency (GWE) were obtained. RESULTS: 1: Patients with SLE demonstrated a significantly reduced GWE and GLS compared with control group, GWW and PSD were increased, above changes were more pronounced in patients with LN. There was no significant difference in GWI and GCW. 2: Receiver operating characteristic (ROC) analysis demonstrated that GWE was the most powerful tool for detecting myocardial insufficiency early in SLE patients, and the area under the curve (AUC) was 0.804, and was superior to GLS (AUC = 0.707). GWE remains the best indicator of subclinical myocardial injury in patients with LN. The AUC was 0.910, and the best cutoff point was 96.5% (sensitivity 83.3%, specificity 73.3%). CONCLUSIONS: LVPSL can be used to noninvasively assess changes in MW in patients with SLE. Noninvasive GWE is a more sensitive index than GLS to detect subclinical myocardial injury early in SLE patients. This is a potential valuable clinical tool to assist in the early-find myocardial damage.

Efficient identification of genomic insertions and flanking regions through whole-genome sequencing in three transgenic soybean events.

Genomic insertions and flanking regions of transgenes in host genomes constitute a critical component of precise molecular characterization and event-specific detection, which are required in the development and assessment for regulatory approval of genetically modified (GM) crops. Previously, we reported three transgenic soybean events harboring the inverted repeats of the soybean mosaic virus NIb (nuclear inclusion b) gene, exhibiting significantly enhanced resistance to multiple Potyvirus strains. To facilitate safety assessment and event-specific detection, we identified the transgene insertion sites and flanking sequences of the events L120, L122, and L123 using whole-genome sequencing. More than 14.48 Gb sequence data (13 × coverage) were generated using the Illumina HiSeq Xten platform for each event. The sequence reads corresponding to boundaries of inserted T-DNA, and associated native flanking sequences were identified by bioinformatic comparison with the soybean reference genome (Wm82.a2.v1) and the transformation vector sequence. The results indicated that two T-DNA insertions occurred in L120, on Chr07 and Chr13, while L122 and L123 showed single insertions, on Chr02 and Chr06, respectively. Based on the flanking sequences of the inserted T-DNA, the event-specific detection for each event was established using specific PCR primers, and PCR amplification followed by sequencing of PCR products further confirmed the putative insertion loci and flanking regions in the transgenic lines. Our results demonstrate the efficacy and robustness of whole-genome sequencing in identifying the genomic insertions and flanking regions in GM crops. Moreover, the characterization of insertion loci and the establishment of event-specific detection will facilitate the application and development of broad-spectrum virus-resistant transgenic soybean cultivars.

Elastin-like polypeptide and γ-zein fusions significantly increase recombinant protein accumulation in soybean seeds.

Soybean seeds are an ideal host for the production of recombinant proteins because of their high content of proteins, long-term stability of seed proteins under ambient conditions, and easy establishment of efficient purification protocols. In this study, a polypeptide fusion strategy was applied to explore the capacity of elastin-like polypeptide (ELP) and γ-zein fusions in increasing the accumulation of the recombinant protein in soybean seeds. Transgenic soybean plants were generated to express the γ-zein- or ELP-fused green fluorescent protein (GFP) under the control of the soybean seed-specific promoter of ß-conglycinin alpha subunit (BCSP). Significant differences were observed in the accumulation of zein-GFP and GFP-ELP from that of the unfused GFP in transgenic soybean seeds based on the total soluble protein (TSP), despite the low-copy of T-DNA insertions and similar expression at the mRNA levels in selected transgenic lines. The average levels of zein-GFP and GFP-ELP accumulated in immature seeds of these transgenic lines were 0.99% and 0.29% TSP, respectively, compared with 0.07% TSP of the unfused GFP. In mature soybean seeds, the accumulation of zein-GFP and GFP-ELP proteins was 1.8% and 0.84% TSP, an increase of 3.91- and 1.82-fold, respectively, in comparison with that of the unfused GFP (0.46% TSP). Confocal laser scanning analysis showed that both zein-GFP and GFP-ELP were abundantly deposited in many small spherical particles of transgenic seeds, while there were fewer such florescence signals in the same cellular compartments of the unfused GFP-expressing seeds. Despite increased recombinant protein accumulation, there were no significant changes in the total protein and oil content in seeds between the transgenic and non-transformed plants, suggesting the possible presence of threshold limits of total protein accumulation in transgenic soybean seeds. Overall, our results indicate that γ-zein and ELP fusions significantly increased the accumulation of the recombinant protein, but exhibited no significant influence on the total protein and oil content in soybean seeds.

Isobaric Labeling Strategy Utilizing 4-Plex N,N-Dimethyl Leucine (DiLeu) Tags Reveals Proteomic Changes Induced by Chemotherapy in Cerebrospinal Fluid of Children with B-Cell Acute Lymphoblastic Leukemia.

The use of mass spectrometry for protein identification and quantification in cerebrospinal fluid (CSF) is at the forefront of research efforts to identify and explore biomarkers for the early diagnosis and prognosis of neurologic disorders. Here we implemented a 4-plex N,N-dimethyl leucine (DiLeu) isobaric labeling strategy in a longitudinal study aiming to investigate protein dynamics in children with B-cell acute lymphoblastic leukemia (B-cell ALL) undergoing chemotherapy. The temporal profile of CSF proteome during chemotherapy treatment at weeks 5, 10-14, and 24-28 highlighted many differentially expressed proteins, such as neural cell adhesion molecule, neuronal growth regulator 1, and secretogranin-3, all of which play important roles in neurodegenerative diseases. A total of 63 proteins were significantly altered across all of the time points investigated. The most over-represented biological processes from gene ontology analysis included platelet degranulation, complement activation, cell adhesion, fibrinolysis, neuron projection, regeneration, and regulation of neuron death. We expect that results from this and future studies will provide a means to monitor neurotoxicity and develop strategies to prevent central nervous system injury in response to chemotherapy in children.

Mass Defect-Based DiLeu Tagging for Multiplexed Data-Independent Acquisition.

The unbiased selection of peptide precursors makes data-independent acquisition (DIA) an advantageous alternative to data-dependent acquisition (DDA) for discovery proteomics, but traditional multiplexed quantification approaches employing mass difference labeling or isobaric tagging are incompatible with DIA. Here, we describe a strategy that permits multiplexed quantification by DIA using mass defect-based N,N-dimethyl leucine (mdDiLeu) tags and high-resolution tandem mass spectrometry (MS2) analysis. Millidalton mass differences between mdDiLeu isotopologues produce fragment ion multiplet peaks separated in mass by as little as 5.8 mDa, enabling up to 4-plex quantification in DIA MS2 spectra. Quantitative analysis of yeast samples displayed comparable accuracy and precision for MS2-based DIA and MS1-based DDA methods. Multiplexed DIA analysis of cerebrospinal fluid revealed the dynamic proteome changes in Alzheimer's disease, demonstrating its utility for discovery of potential clinical biomarkers. We show that the mdDiLeu tagging approach for multiplexed DIA is a viable methodology for investigating proteome changes, particularly for low-abundance proteins, in different biological matrices.

Enhanced tolerance to Phytophthora root and stem rot by over-expression of the plant antimicrobial peptide CaAMP1 gene in soybean.

BACKGROUND: Antimicrobial peptides play important roles in both plant and animal defense systems. Moreover, over-expression of CaAMP1 (Capsicum annuum antimicrobial protein 1), an antimicrobial protein gene isolated from C. annuum leaves infected with Xanthomonas campestris pv. vesicatoria, confers broad-spectrum resistance to hemibiotrophic bacterial and necrotrophic fungal pathogens in Arabidopsis. Phytophthora root and stem rot (PRR), caused by the fungus Phytophthora sojae, is one of the most devastating diseases affecting soybean (Glycine max) production worldwide. RESULTS: In this study, CaAMP1 was transformed into soybean by Agrobacterium-mediated genetic transformation. Integration of the foreign gene in the genome of transgenic soybean plants and its expression at the translation level were verified by Southern and western blot analyses, respectively. CaAMP1 over-expression (CaAMP1-OX) lines inoculated with P. sojae race 1 exhibited enhanced and stable PRR tolerance through T2-T4 generations compared with the wild-type Williams 82 plants. Gene expression analyses in the transgenic plants revealed that the expression of salicylic acid-dependent, jasmonic acid-dependent, and plant disease resistance genes (R-genes) were significantly up-regulated after P. sojae inoculation. CONCLUSIONS: These results indicate that CaAMP1 over-expression can significantly enhance PRR tolerance in soybean by eliciting resistance responses mediated by multiple defense signaling pathways. This provides an alternative approach for developing soybean varieties with improved tolerance against soil-borne pathogenic PRR.

Nanomedicines based on nanoscale metal-organic frameworks for cancer immunotherapy.

Cancer immunotherapy, with an aim to enhance host immune responses, has been recognized as a promising therapeutic treatment for cancer. A diversity of immunomodulatory agents, including tumor-associated antigens, adjuvants, cytokines and immunomodulators, has been explored for their ability to induce a cascading adaptive immune response. Nanoscale metal-organic frameworks (nMOFs), a class of crystalline-shaped nanomaterials formed by the self-assembly of organic ligands and metal nodes, are attractive for cancer immunotherapy because they feature tunable pore size, high surface area and loading capacity, and intrinsic biodegradability. In this review we summarize recent progress in the development of nMOFs for cancer immunotherapy, including cancer vaccine delivery and combination of in situ vaccination with immunomodulators to reverse immune suppression. Current challenges and future perspectives for rational design of nMOF-based cancer immunotherapy are also discussed.

High-Resolution Enabled 5-plex Mass Defect-Based N, N-Dimethyl Leucine Tags for Quantitative Proteomics.

A mass defect-based labeling strategy provides high accuracy as an MS1-centric quantification method, avoiding the ratio compression that affects isobaric label-based reporter ion quantification. We have developed cost-effective 5-plex mass defect N, N-dimethyl leucine (mdDiLeu) tags for quantification of various biological samples with increased multiplexing at a given resolving power afforded by the addition of mass difference isotopologues. The combination of mass difference and mass defect produces two labeled peak clusters separated by 5 Da in MS1 spectra that are detected as five isotopic peaks at high resolution with mass differences of 15, 17, and 18 mDa per tag. Synthesis of each of the 5-plex mdDiLeu tags is accomplished by a single straightforward reaction step, making it accessible to any lab. To demonstrate 5-plex mdDiLeu for quantitative proteomics, we perform proof-of-principle experiments of mdDiLeu-labeled Saccharomyces cerevisiae lysate digest on an Orbitrap Fusion Lumos mass spectrometer.

HOTMAQ: A Multiplexed Absolute Quantification Method for Targeted Proteomics.

Absolute quantification in targeted proteomics is challenging due to a variety of factors, including low specificity in complex backgrounds, limited analytical throughput, and wide dynamic range. To address these problems, we developed a hybrid offset-triggered multiplex absolute quantification (HOTMAQ) strategy that combines cost-effective mass difference and isobaric tags to enable simultaneous construction of an internal standard curve in the MS1 precursor scan, real-time identification of peptides at the MS2 level, and mass offset-triggered accurate quantification of target proteins in synchronous precursor selection (SPS)-MS3 spectra. This approach increases the analytical throughput of targeted quantitative proteomics by up to 12-fold. The HOTMAQ strategy was employed to verify candidate protein biomarkers in preclinical Alzheimer's disease with high accuracy. The greatly enhanced throughput and quantitative performance, paired with sample flexibility, makes HOTMAQ broadly applicable to targeted peptidomics, proteomics, and phosphoproteomics.

Electrophilic probes for deciphering substrate recognition by O-GlcNAc transferase.

O-linked ß-N-acetylglucosamine (O-GlcNAc) transferase (OGT) is an essential human glycosyltransferase that adds O-GlcNAc modifications to numerous proteins. However, little is known about the mechanism with which OGT recognizes various protein substrates. Here we report on GlcNAc electrophilic probes (GEPs) to expedite the characterization of OGT-substrate recognition. Data from mass spectrometry, X-ray crystallization, and biochemical and radiolabeled kinetic assays support the application of GEPs to rapidly report the impacts of OGT mutations on protein substrate or sugar binding and to discover OGT residues crucial for protein recognition. Interestingly, we found that the same residues on the inner surface of the N-terminal domain contribute to OGT interactions with different protein substrates. By tuning reaction conditions, a GEP enables crosslinking of OGT with acceptor substrates in situ, affording a unique method to discover genuine substrates that weakly or transiently interact with OGT. Hence, GEPs provide new strategies to dissect OGT-substrate binding and recognition.