Effects of tacrolimus on proteinuria in Chinese and Indian patients with idiopathic membranous nephropathy: the results of machine learning study.

PURPOSE: The present study aims to explore the effects of tacrolimus on proteinuria in patients with idiopathic membranous nephropathy (IMN) and recommend an appropriate dosage schedule via machine learning method. METHODS: The Emax model was constructed to analyze the effects of tacrolimus on proteinuria in patients with IMN. Data were mined from published literature and machine learning was built up with Emax model, among which the efficacy indicator was proteinuria change rates from baseline. 463 IMN patients were included for modeling, and tacrolimus therapeutic window concentrations were 4-10 ng/ml. RESULTS: In machine learning model, the Emax from tacrolimus effecting proteinuria in IMN patients was -72.7%, the ET50 was 0.43 months, and the time to achieving 25% Emax, 50% Emax, 75% Emax, and 80% (plateau) Emax of tacrolimus on proteinuria in patients with IMN were 0.15, 0.43, 1.29, and 1.72 months, respectively. CONCLUSION: For achieving better therapeutic effects from tacrolimus on proteinuria in patients with IMN, tacrolimus concentration range need to be maintained at 4-10 ng/ml for at least 1.72 months.

The Impact of Spironolactone Co-administration on Cyclosporin Initial Dosage Optimization for Pediatric Refractory Nephrotic Syndrome.

OBJECTIVES: Cyclosporin has been used for the treatment of pediatric refractory nephrotic syndrome (PRNS). However, the narrow therapeutic window and large pharmacokinetic variability make it difficult to individualize cyclosporin administration. Meanwhile, spironolactone has been reported to affect cyclosporin metabolism in PRNS patients. This study aims to explore the initial dosage optimization of cyclosporin in PRNS based on the impact of spironolactone co-administration. METHODS: Monte Carlo simulation based on a previously established cyclosporin population pharmacokinetic model for PRNS was used to design cyclosporin dosing regimen. RESULTS: In this study, the probability of drug concentration reaching the target and the convenience of times of administration were considered comprehensively. The optimal administration regimen in PRNS without spironolactone was 6, 5, 4 and 3 mg/kg cyclosporin split into two doses for the body weight of 5-8, 8-18, 18-46 and 46-70 kg, respectively. The optimal administration regimen in PRNS with spironolactone was 4, 3, 2 mg/kg cyclosporin split into two doses for body weight of 5-14, 14-65, and 65-70 kg, respectively. CONCLUSION: The cyclosporin dosing regimen for PRNS based on Monte Carlo simulation was systematically developed and the initial dosage optimization of cyclosporin in PRNS was recommended for the first time.

The effects of a plate model on the remission and need for hypoglycemic drugs of newly diagnosed type 2 diabetes in China: A randomized trial.

To assess the effect of the plate model on the remission of diabetes and the demand for hypoglycemic drugs in China. We selected 456 participants with newly diagnosed type 2 diabetes and not required to take hypoglycemic drugs at baseline. The plate education model consists of three parts: a colored leaflet suitable for low literacy reading, regular medical visits and health education sessions. The primary outcomes were remission of diabetes and the time to first use of hypoglycemic drugs. The study was ended after 8.1 years of follow-up. The incidence of the using hypoglycemic drugs was 36.15 % in the plate model, and 75.54 % in the low-fat model (P < 0.001). The prevalence of any remission in plate model was 27.1 % (95 % CI 16.8-37.4 %) during the first 2 years, decreasing to 14.5 % (95 % CI 6.3-22.7 %) during year 4, to 10.1 % (95 % CI 4.4-15.8 %) during year 6, and to 9.6 % (95 % CI 5.3-13.9 %) during year 8, compared with 12.2 % (95 % CI 5.2-19.2 %) at year 2, 6.1 % (95 % CI 2.1-10.1 %) at year 4, 4.7 %(95 % CI 2.2-7.2 %) at year 6, and 2.6 % (95 % CI 1.1-4.2 %) at year 8 in the low-fat group. The HbA1c of plate group was significantly decreased at the endpoint (7.74 ± 0.45 % vs. 6.70 ± 0.46 %, P < 0.001). The plate model may significantly improve the remission rate of diabetes, delay the demand for diabetes drugs, more suitable for patients with low educational level, and reduce the long-term level of HbA1c. Clinical trials registry: The study was registered at ChiCTR (www.chictr.org.cn) (ChiCTR1900027097).

Association of mobile phone usage time with incidence of diabetic retinopathy in type 2 diabetes: a prospective cohort study.

We prospectively analyzed the association between mobile phone usage time and the incidence of diabetic retinopathy (DR) in type 2 diabetes (T2D) among participants.We included a total of 4,371 patients with T2D among the participants. Mobile phone usage time was quantified at baseline by summing up the hours spent on mobile phone use. The types of mobile phone usage time in our study include game time, TikTok time, WeChat time, watching movies or reading time, and online shopping time. We categorized patients into four groups according to different mobile phone usage time: ≤1.5 h/day (n = 1,101), 1.6-3.5 h/day (n = 1,098), 3.6-7.5 h/day (n = 1,095), and >7.6 h/day (n = 1,077). Fundus photography was performed every year from January 2012 to January 2020. During a follow-up of 8 years, 1,119 were affected by DR, resulting in an overall incidence of 25.6%. The incidences of mild nonproliferative DR (NPDR), moderate NPDR, severe NPDR, and proliferative DR (PDR) were 10.1%, 5.1%, 5.1%, and 5.2%, respectively. In comparisons with participants in the lowest category (≤1.5 h/day), the hazard ratios (HRs) of DR were 1.19 (95% confidence interval [CI] 1.07, 1.31, p = 0.040) for 1.6-3.5 h/day, 1.60 (95% CI 1.40, 1.81, p < 0.001) for 3.6-7.5 h/day, and 1.85 (95% CI 1.61, 2.09, p < 0.001) for >7.6 h/day, respectively. Our results provide the general population with a feasible and practical alternative for the reduction of mobile phone use behavior time and new measures to prevent the occurrence of DR.

Effectiveness of restricted diet with a plate in patients with type 2 diabetes: A randomized controlled trial.

BACKGROUND: In view of the complexity of dietary and nutritional education for most patients with type 2 diabetes mellitus (T2DM), a simplified approach called the "restricted diet with a plate" or "plate model" is recommended. PURPOSE: To evaluate whether the plate model can effectively improve glycemic control and cardiovascular risk markers in type 2 diabetes mellitus (T2DM), while reducing the time devoted to education and avoiding weight gain. METHODS: The study was a randomized, multicenter, controlled study, conducted between October 2018 and October 2019, among patients with T2DM living in Nanjing. The study included 419 participants who were randomly divided into a plate group and a counting group. The plate model included three components: a low-literacy, color leaflet containing the explanation and composition of the plate model, health education, and medical visits. Patients in the counting group received health education, group medical visits, and a paper booklet containing traditional carbohydrate counting education. Primary outcomes were glycemic control and weight. RESULTS: Participants in the plate model reduced HbA1c by 0.7% in the first three months, and reduced to a greater extent at six months (1.44%), but this was not sustained, and HbA1c increased slightly over the following six months. Fasting plasma glucose (FPG) and 2-h postprandial glucose (2hPG) values were significantly reduced at the endpoint in the plate model (9.25 ± 1.72% vs. 7.44 ± 0.88%, P = 0.008; 12.07 ± 2.94 vs. 8.35 ± 1.99%; P = 0.004); however, the 2hPG values decreased most significantly. Total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) levels decreased significantly in the plate group, which occurred at six months and lasted for 12 months. In the first three months, the average weight loss in the plate group was 1.2 kg/month (95% CI 0.92-1.48), and in the fourth to twelfth months, the average weight gain was 0.21 kg/month (95% CI 0.08-0.34). There was significant difference in education time between the groups (17.3 ± 4.42 vs. 38.6 ± 12.63; P < 0.001). CONCLUSIONS: The plate model is at least as effective as the counting model over the short term for glycemic control and perhaps even better for weight and lipid control. Plate model has the potential to improve education of those with low health literacy by reducing reading demands.

SDF-1 secreted by mesenchymal stem cells promotes the migration of endothelial progenitor cells via CXCR4/PI3K/AKT pathway.

Cell-based therapeutics bring great hope in areas of unmet medical needs. Mesenchymal stem cells (MSCs) have been suggested to facilitate neovascularization mainly by paracrine action. Endothelial progenitor cells (EPCs) can migrate to ischemic sites and participate in angiogenesis. The combination cell therapy that includes MSCs and EPCs has a favorable effect on ischemic limbs. However, the mechanism of combination cell therapy remains unclear. Herein, we investigate whether stromal cell-derived factor (SDF)-1 secreted by MSCs contributes to EPC migration to ischemic sites via CXCR4/Phosphoinositide 3-Kinases (PI3K)/protein kinase B (termed as AKT) signaling pathway. First, by a "dual-administration" approach, intramuscular MSC injections were supplemented with intravenous Qdot® 525 labeled-EPC injections in the mouse model of hind limb ischemia. Then, the mechanism of MSC effect on EPC migration was detected by the transwell system, tube-like structure formation assays, western blot assays in vitro. Results showed that the combination delivery of MSCs and EPCs enhanced the incorporation of EPCs into the vasculature and increased the capillary density in mouse ischemic hind limb. The numbers of CXCR4-positive EPCs increased after incubation with MSC-conditioned medium (CM). MSCs contributed to EPC migration and tube-like structure formation, both of which were suppressed by AMD3100 and wortmannin. Phospho-AKT induced by MSC-CM was attenuated when EPCs were pretreated with AMD3100 and wortmannin. In conclusion, we confirmed that MSCs contributes to EPC migration, which is mediated via CXCR4/PI3K/AKT signaling pathway.

Neuropsychiatric Lupus Erythematosus: Future Directions and Challenges; a Systematic Review and Survey.

This study aimed to systematically review neuropsychiatric lupus erythematosus (NPSLE) and establish a simplified diagnostic criterion for NPSLE. Publications from 1994 to 2018 in the database (Wanfang data (http://www.wanfangdata.com.cn/index.html) and China National Knowledge Internet (http://www.cnki.net)) were included. In total, 284 original case reports and 24 unpublished cases were collected, and clinical parameters were analyzed. An attempt was made to develop a set of simplified diagnostic criteria for NPSLE based on cases described in the survey and literature; moreover, and pathophysiology and management guidelines were studied. The incidence rate of NPSLE was estimated to be 12.4% of SLE patients in China. A total of 408 NPSLE patients had 652 NP events, of which 91.2% affected the central nervous system and 8.8% affected the peripheral nervous system. Five signs (manifestations, disease activity, antibodies, thrombosis, and skin lesions) showed that negative and positive predictive values were more than 70%, included in the diagnostic criteria. The specificity, accuracy, and positive predictive value (PPV) of the revised diagnostic criteria were significantly higher than those of the American College of Rheumatology (ACR) criteria (χ2=13.642, 15.591, 65.010, p<0.001). The area under the curve (AUC) for revised diagnostic criteria was 0.962 (standard error=0.015, 95% confidence intervals [CI] =0.933-0.990), while the AUC for the ACR criteria was 0.900 (standard error=0.024, 95% CI=0.853-0.946). The AUC for the revised diagnostic criteria was different from that for the ACR criteria (Z=2.19, p<0.05). Understanding the pathophysiologic mechanisms leading to NPSLE is essential for the evaluation and design of effective interventions. The set of diagnostic criteria proposed here represents a simplified, reliable, and cost-effective approach used to diagnose NPSLE. The revised diagnostic criteria may improve the accuracy rate for diagnosing NPSLE compared to the ACR criteria.

Neuropsychiatric lupus erythematosus: future directions and challenges; a systematic review and survey

This study aimed to systematically review neuropsychiatric lupus erythematosus (NPSLE) and establish a simplified diagnostic criterion for NPSLE. Publications from 1994 to 2018 in the database (Wanfang data (http://www.wanfangdata.com.cn/index.html) and China National Knowledge Internet (http://www.cnki.net)) were included. In total, 284 original case reports and 24 unpublished cases were collected, and clinical parameters were analyzed. An attempt was made to develop a set of simplified diagnostic criteria for NPSLE based on cases described in the survey and literature; moreover, and pathophysiology and management guidelines were studied. The incidence rate of NPSLE was estimated to be 12.4% of SLE patients in China. A total of 408 NPSLE patients had 652 NP events, of which 91.2% affected the central nervous system and 8.8% affected the peripheral nervous system. Five signs (manifestations, disease activity, antibodies, thrombosis, and skin lesions) showed that negative and positive predictive values were more than 70%, included in the diagnostic criteria. The specificity, accuracy, and positive predictive value (PPV) of the revised diagnostic criteria were significantly higher than those of the American College of Rheumatology (ACR) criteria (χ2=13.642, 15.591, 65.010, p<0.001). The area under the curve (AUC) for revised diagnostic criteria was 0.962 (standard error=0.015, 95% confidence intervals [CI] =0.933-0.990), while the AUC for the ACR criteria was 0.900 (standard error=0.024, 95% CI=0.853-0.946). The AUC for the revised diagnostic criteria was different from that for the ACR criteria (Z=2.19, p<0.05). Understanding the pathophysiologic mechanisms leading to NPSLE is essential for the evaluation and design of effective interventions. The set of diagnostic criteria proposed here represents a simplified, reliable, and cost-effective approach used to diagnose NPSLE. The revised diagnostic criteria may improve the accuracy rate for diagnosing NPSLE compared to the ACR criteria.

Long noncoding RNA ABHD11-AS1 promote cells proliferation and invasion of colorectal cancer via regulating the miR-1254-WNT11 pathway.

The purpose of our study was to investigate the effects of the long noncoding RNA (lncRNA) ABHD11-AS1 on colorectal cancer (CRC) progression and further explore its possible underlying mechanisms. In the study, we found that ABHD11-AS1 was highly expressed in CRC tissues and cell lines. High ABHD11-AS1 expression was correlated with poor overall survival of patients with CRC. ABHD11-AS1 knockdown reduced CRC cell proliferation, in vitro invasion, and in vivo tumor growth. Investigation of the underlying mechanism showed that ABHD11-AS1 could act as a molecular sponge of miR-1254, and WNT11 was a downstream target of miR-1254 in CRC. Moreover, there was a negative association between ABHD11-AS1 expression (or WNT11) and miR-1254 in CRC tissues. The rescue assays showed that WNT11 overexpression partially rescued the effects of ABHD11-AS1 inhibition on CRC progression. Thus, we demonstrated that ABHD11-AS1 promotes CRC progression through the miR-1254-WNT11 pathway, which provides a new insight into the therapeutic strategies for CRC.

In-depth analysis of secretome and N-glycosecretome of human hepatocellular carcinoma metastatic cell lines shed light on metastasis correlated proteins.

Cancer cell metastasis is a major cause of cancer fatality. But the underlying molecular mechanisms remain incompletely understood, which results in the lack of efficient diagnosis, therapy and prevention approaches. Here, we report a systematic study on the secretory proteins (secretome) and secretory N-glycoproteins (N-glycosecretome) of four human hepatocellular carcinoma (HCC) cell lines with different metastatic potential, to explore the molecular mechanism of metastasis and supply the clues for effective measurement of diagnosis and therapy. Totally, 6242 unique gene products (GPs) and 1637 unique N-glycosites from 635 GPs were confidently identified. About 4000 GPs on average were quantified in each of the cell lines, 1156 of which show differential expression (p<0.05). Ninety-nine percentage of the significantly altered proteins were secretory proteins and proteins correlated to cell movement were significantly activated with the increasing of metastatic potential of the cell lines. Twenty-three GPs increased both in the secretome and the N-glycosecretome were chosen as candidates and verified by western blot analysis, and 10 of them were chosen for immunohistochemistry (IHC) analysis. The cumulative survival rates of the patients with candidate (FAT1, DKK3) suggested that these proteins might be used as biomarkers for HCC diagnosis. In addition, a comparative analysis with the published core human plasma database (1754 GPs) revealed that there were 182 proteins not presented in the human plasma database but identified by our studies, some of which were selected and verified successfully by western blotting in human plasma.

Lamotrigine attenuates cerebral ischemia-induced cognitive impairment and decreases ß-amyloid and phosphorylated tau in the hippocampus in rats.

Lamotrigine (LTG) has shown benefits in animal models of cerebral ischemia, but the mechanism involved was not fully studied. This study was carried out to examine the effects of LTG on cognitive dysfunction, ß-amyloid1-42 accumulation, and tau protein hyperphosphorylation in the hippocampus of ischemic rats. Transient ischemic stroke was induced by middle cerebral artery occlusion. The Morris water maze test was used to evaluate the cognitive function of rats. We found that LTG significantly attenuated ischemia-induced cognitive deficits and decreased neuronal injury in the hippocampal CA1 zone. Moreover, LTG reduced ß-amyloid1-42 and phosphorylated tau (AT8) in the hippocampus after ischemia. These results suggested that the cognition-protective effects of LTG after cerebral ischemia might involve inhibition of toxic ß-amyloid accumulation and tau hyperphosphorylation in the hippocampus.

[Preliminary analysis of bitter substances in spica of Prunella vulgaris].

Volatile oil components and the contents and types of amino acid in spica of Prunella vulgaris were analysed by GC-MS and amino acid analyzer. Esters, fatty acids, aromatic hydrocarbon, ketone and several alcohol compounds were identified by mass spectrum comparison. In these ingredients, beta-ionone smelled aroma of cedar, raspberry, nerolidol showed weak sweet soft orange blossom flavor, neroli tasted sweet and fresh, nerolidol tasted sweet with light aroma of wood, hexadecanal showed a weak aroma of flowers and wax, alpha-sinensal had rich and fresh sweet orange flavor. To some extent, these types of aromatic substances can affect the taste of herbal tea or decoction made of Spica Prunellae. Among amino acids detected, natural amino acids accounted for a larger proportion, and those natural amino acids showed bitterness, slight bitterness, sourness (freshness), sweetness, slight sweetness, sourness (slight freshness). The results indicated that bitter and slightly bitter amino acids have the greatest impacts on the sense of Spica Prunellae.

N-glycoproteome analysis of the secretome of human metastatic hepatocellular carcinoma cell lines combining hydrazide chemistry, HILIC enrichment and mass spectrometry.

Cancer cell metastasis is a major cause of cancer death. Unfortunately, the underlying molecular mechanisms remain unknown, which results in the lack of efficient diagnosis, therapy and prevention approaches. Nevertheless, the dysregulation of the cancer cell secretome is known to play key roles in tumor transformation and progression. The majority of proteins in the secretome are secretory proteins and membrane-released proteins, and, mostly, the glycosylated proteins. Until recently, few studies have explored protein N-glycosylation changes in the secretome, although protein glycosylation has received increasing attention in the study of tumor development processes. Here, the N-glycoproteins in the secretome of two human hepatocellular carcinoma (HCC) cell lines with low (MHCC97L) or high (HCCLM3) metastatic potential were investigated with a in-depth characterization of the N-glycosites by combining two general glycopeptide enrichment approaches, hydrazide chemistry and zwitterionic hydrophilic interaction chromatography (zic-HILIC), with mass spectrometry analysis. A total of 1,213 unique N-glycosites from 611 N-glycoproteins were confidently identified. These N-glycoproteins were primarily localized to the extracellular space and plasma membrane, supporting the important role of N-glycosylation in the secretory pathway. Coupling label-free quantification with a hierarchical clustering strategy, we determined the differential regulation of several N-glycoproteins that are related to metastasis, among which AFP, DKK1, FN1, CD151 and TGFß2 were up-regulated in HCCLM3 cells. The inclusion of the well-known metastasis-related proteins AFP and DKK1 in this list provides solid supports for our study. Further western blotting experiments detecting FN1 and FAT1 confirmed our discovery. The glycoproteome strategy in this study provides an effective means to explore potential cancer biomarkers.

N-linked glycoproteome profiling of human serum using tandem enrichment and multiple fraction concatenation.

N-linked glycosylation is an important protein posttranslational modification that is involved in numerous biological processes. Different methods, including chemical reaction and affinity interaction, have been developed to enrich glycosylated peptides or proteins from biological systems. However, due to the common occurrence of low glycosites occupancy in proteins and the low efficiency of enrichment approaches, only a small fraction of protein glycosites have been reported. In this study, we combined the glycopeptide enrichment strategy for broad analysis of human serum N-glycoproteins using a tandem enrichment method coupling lectin affinity capture with HILIC. This strategy was applied to profile the human serum N-linked glycoproteome, and it resulted in 32 and 14% more N-glycosites than could be identified with the common lectin affinity capture or HILIC approaches, respectively. With an additional dimension of glycopeptides separation using high-pH reversed phase liquid chromatography or off-gel electrophoresis, the number of identified glycosites was increased by 3.1-fold and 1.8-fold, respectively. These results demonstrate that tandem enrichment methods, especially when followed by high-pH reversed-phase prefractionation, can greatly improve the power of N-glycoproteome analysis. In total, 615 N-glycosites from 312 glycoproteins (protein group) were mapped using high-accuracy mass spectrometry.

Comparison and optimization of strategies for a more profound profiling of the sialylated N-glycoproteomics in human plasma using metal oxide enrichment.

Glycosylation is an important posttranslational modification of proteins and plays a crucial role in both cellular functions and secretory pathways. Sialic acids (SAs), a family of nine-carbon-containing acidic monosaccharides, often terminate the glycan structures of cell surface molecules and secreted glycoproteins and perform an important role in many biological processes. Hence, a more profound profiling of the sialylated glycoproteomics may improve our knowledge of this modification and its effects on protein functions. Here, we systematically investigated different strategies to enrich the SA proteins in human plasma using a newly developed technology that utilizes titanium dioxide for sialylated N-glycoproteomics profiling by mass spectrometry. Our results showed that using a combination of a filter-aided sample preparation method, TiO2 chromatography, multiple enzyme digestion, and two-dimensional reversed-phase peptide fractionation led to a more profound profiling of the SA proteome. In total, 982 glycosylation sites in 413 proteins were identified, among which 37.8% were newly identified, to establish the largest database of sialic acid containing proteins from human plasma.

A highly efficient and visualized method for glycan enrichment by self-assembling pyrene derivative functionalized free graphene oxide.

Protein glycosylation plays key roles in many biological processes, such as cell growth, differentiation, and cell-cell recognition. Therefore, global structure profiling of glycans is very important for investigating the biological significance and roles of glycans in disease occurrence and development. Mass spectrometry (MS) is currently the most powerful technique for structure analysis of oligosaccharides, but the limited availability of glycan/glycoproteins from natural sources restricts the wide adoption of this technique in large-scale glycan profiling. Though various enrichment methods have been developed, most methods relay on the weak physical affinity between glycans and adsorbents that yields insufficient enrichment efficiency. Furthermore, the lack of monitoring the extent/completeness of enrichment may lead to incomplete enrichment unless repeated sample loading and prolonged incubation are adopted, which limits sample handling throughput. Here, we report a rapid, highly efficient, and visualized approach for glycan enrichment using 1-pyrenebutyryl chloride functionalized free graphene oxide (PCGO). In this approach, glycan capturing is achieved by reversible covalent bond formation between the hydroxyl groups of glycans and the acyl chloride groups on graphene oxide (GO) introduced by π-π stacking of 1-pyrenebutyryl chloride on the GO surface. The multiple hydroxyl groups of glycans lead to cross-linking and self-assembly of free PCGO sheets into visible aggregation within 30 s, therefore achieving simple visual monitoring of the enrichment process. Improved enrichment efficiency is achieved by the large specific surface area of free PCGO and heavy functionalization of highly active 1-pyrenebutyryl chloride. Application of this method in enrichment of standard oligosaccharides or N-glycans released from glycoproteins results in remarkably increased MS signal intensity (approximately 50 times), S/N, and number of glycoform identified.

Comprehensive characterization of the N-glycosylation status of CD44s by use of multiple mass spectrometry-based techniques.

The CD44 family are type-1 transmembrane glycoproteins which are important in mediating the response of cells to their microenvironment, including regulation of growth, survival, differentiation, and motility. All these important functions have been reported to be regulated by N-glycosylation; however, little is known about this process. In the CD44 family, the most prolific isoform is CD44 standard type (CD44s). In this work, an integrated strategy combining stable isotope labeling, chemical derivatization, hydrophilic-interaction liquid chromatographic (HILIC) separation, and mass spectrometric (MS) identification was used to perform a comprehensive qualitative and quantitative survey of the N-glycosylation of recombinant CD44s. Specifically, the occupation ratios of the N-glycosites were first determined by MS with (18)O labeling; the results revealed five glycosites with different occupation ratios. Next, N-glycans were profiled by chemical derivatization and exoglycosidase digestion, followed by MALDI-TOF-MS and HILIC-ESI-MS-MS analysis. Interestingly, the quantitative analysis showed that non-sialylated, fucosylated complex-type glycans dominated the N-glycans of CD44s. Furthermore, the site-specific N-glycan distributions profiled by LC-ESI-MS(E) indicated that most glycosites bore complex-type glycans, except for glycosite N100, which was occupied by high-mannose-type N-glycans. This is the first comprehensive report of the N-glycosylation of CD44s. Figure Strategies for characterization of the N-glycosylation status of CD44s.

Characterization of glycoprotein digests with hydrophilic interaction chromatography and mass spectrometry.

A new hydrophilic interaction chromatography (HILIC) column packed with amide 1.7 µm sorbent was applied to the characterization of glycoprotein digests. Due to the impact of the hydrophilic carbohydrate moiety, glycopeptides were more strongly retained on the column and separated from the remaining nonglycosylated peptides present in the digest. The glycoforms of the same parent peptide were also chromatographically resolved and analyzed using ultraviolet and mass spectrometry detectors. The HILIC method was applied to glyco-profiling of a therapeutic monoclonal antibody and proteins with several N-linked and O-linked glycosylation sites. For characterization of complex proteins with multiple glycosylation sites we utilized 2D LC, where RP separation dimension was used for isolation of glycopeptides and HILIC for resolution of peptide glycoforms. The analysis of site-specific glycan microheterogeneity was illustrated for the CD44 fusion protein.

High-throughput antibody generation using multiplexed immunization and immunogen array analysis.

In this work, the authors developed a new screening approach using multiplexed immunization and immunogen array analysis to improve the efficiency of antibody screening for high-throughput antibody generation. The immunogen array is based on a 96-well format in which different immunogens and negative as well as positive controls are immobilized in each well, thus making it possible to screen hundreds of antibody candidates simultaneously. To demonstrate this approach, a model of 4 mixed immunogens immunization was employed. In total, 675 antibody candidates were screened before and after established antibody hybridomas in parallel with immunogen arrays and enzyme-linked immunosorbent assay. The signal intensity, specificity, and cross-reactivity of produced antibody candidates were analyzed using a hierarchical cluster algorithm to track the characteristics of antibody candidates during antibody generation, which might reduce the number of false-positive and false-negative binding of antibodies. Moreover, 4 monoclonal antibodies that were produced successfully recognized their corresponding target antigens.

Application of open tubular capillary columns coated with zirconium phosphonate for enrichment of phosphopeptides.

A new approach utilizing open tubular capillary columns coated with zirconium phosphonate (ZrP-OTCC) for enrichment of phosphopeptides is described. The experimental conditions: interior diameter, length of capillary and flow rate was optimized using tryptic digest of alpha-casein (a phosphoprotein) as a model sample. The ZrP-OTCC was demonstrated to tolerate urea, sodium dodecyl sulphate (SDS), and NaCl. Further experimental results show that the ZrP-OTCC can trap the phosphopeptides even at the concentration of alpha-casein as low as 10(-8)M. This column has also been successfully coupled online with nano-liquid chromatography for enrichment and then separation of phosphopeptides from a complex sample, and finally analyzed the phosphopeptides by mass spectrometry (MS).