Optimization of lactic acid bacterial starter culture to improve the quality and flavor characteristics of traditional Hurood.

Hurood is a traditional fermented milk product prepared by traditional Mongolian techniques of fermenting raw milk, partial degreasing, heating, whey drainage, emulsification of curd, and molding. Currently, Hurood available in the market is generally prepared by small-scale enterprises at home or in open air. Therefore, lack of standardization of bacterial starter culture leads to variation in the flavor and sensory properties of Hurood from batch to batch. In this study, we aimed to assess the best starter culture combination obtained from 37 lactic acid bacterial strains isolated from traditional Hurood. The solidification state and sensory quality were used as indexes for determining the fermentation efficiency of the bacterial starter culture combinations. The yield and texture characteristics were used to determine the optimal ratio of bacterial strains in a combination and the processing conditions for traditional Hurood production. The most optimal bacterial culture combination was observed to be NF 9-3:NF 10-4:CH 3-1 in 5:4:1 ratio and in 3% amount. The most optimal whey temperature and heating-stirring temperature were observed to be 55°C to 60°C and 85°C to 90°C, respectively. Hurood prepared with the optimal combination of bacterial strains exhibited significantly enhanced sensory quality, flavor, and contents of AA and fatty acids. Therefore, the use of optimal starter culture of lactic acid bacteria could produce Hurood with significantly superior sensory qualities, making the product more acceptable to consumers.

PADI4 Epigenetically Suppresses p21 Transcription and Inhibits Cell Apoptosis in Fibroblast-like Synoviocytes from Rheumatoid Arthritis Patients.

Rheumatoid arthritis (RA) is characterized by synovial lining hyperplasia, which involves abnormal growth of fibroblast-like synoviocytes (FLSs). This study aimed to investigate the function and molecular mechanism of peptidylarginine deiminase type 4 (PADI4) in FLSs isolated from RA patients (RA-FLSs). FLSs were isolated from RA patients and transfected with small interfering RNAs (siRNAs) or PADI4 overexpression plasmid. FLSs were treated by Adriamycin (ADR) to induce apoptosis, and apoptotic cells were detected by flow cytometry. The expression of PADI4, p53 and p21 was detected by qRT-PCR and Western blot analysis. The recruitment of PADI4 and histone H3 arginine modifications to p21 promoter was measured by chromatin immunoprecipitation. The results showed that knockdown of PADI4 promoted the apoptosis of RA-FLSs and the expression of p53 and p21. Ectopic expression of PADI4 inhibited ADR-induced apoptosis of RA-FLSs, and down-regulated the expression of p53 and p21. In RA-FLSs, global H3 citrullination (CitH3) and H3 arginine 17 methylation levels were dynamically changed by PADI4 and ADR treatment. PADI4 and H3 could bind p21 promoter region to regulate p21 expression. In conclusion, PADI4 contributes to the pathogenesis of RA by protecting FLSs from apoptosis. PADI4 suppresses p21 transcription through altering histone H3 arginine modifications on p21 promoter region. Our study provides new insight into the anti-apoptotic role of PADI4 in RA development.

Glucose-6-Phosphate Isomerase (G6PI) Mediates Hypoxia-Induced Angiogenesis in Rheumatoid Arthritis.

The higher level of Glucose-6-phosphate isomerase (G6PI) has been found in both synovial tissue and synovial fluid of rheumatoid arthritis (RA) patients, while the function of G6PI in RA remains unclear. Herein we found the enrichment of G6PI in microvascular endothelial cells of synovial tissue in RA patients, where a 3% O2 hypoxia environment has been identified. In order to determine the correlation between the high G6PI level and the low oxygen concentration in RA, a hypoxia condition (~3% O2) in vitro was applied to mimic the RA environment in vivo. Hypoxia promoted cellular proliferation of rheumatoid arthritis synovial fibroblasts (RASFs), and induced cell migration and angiogenic tube formation of human dermal microvascular endothelial cells (HDMECs), which were accompanied with the increased expression of G6PI and HIF-1α. Through application of G6PI loss-of-function assays, we confirmed the requirement of G6PI expression for those hypoxia-induced phenotype in RA. In addition, we demonstrated for the first time that G6PI plays key roles in regulating VEGF secretion from RASFs to regulate the hypoxia-induced angiogenesis in RA. Taken together, we demonstrated a novel pathway regulating hypoxia-induced angiogenesis in RA mediated by G6PI.

Growth differentiation factor 15, ischemia modified albumin and pregnancy-associated plasma protein A in patients with coronary artery disease.

BACKGROUND: Growth differentiation factor 15 (GDF-15), ischemia modified albumin (IMA) might aid in the early diagnosis and risk stratification of patients with coronary artery disease (CAD), while pregnancy associated plasma protein-A (PAPP-A) can serve as a useful marker of vulnerable plaques and acute coronary syndrome (ACS). We sought to determine serum levels of GDF-15, IMA, PAPP-A and evaluate their diagnostic value in different types of CAD. METHODS: We detected serum levels of GDF-15, IMA and PAPP-A in 348 patients with CAD and 205 controls. Levels of high-sensitivity C reactive protein, creatine kinase isoenzyme MB, and high-sensitivity cardiac troponin-T, which represent biomarkers of inflammation, damage or necrosis, were also evaluated. RESULTS: There were significant differences of GDF-15, IMA and PAPP-A in patients with CAD compared with the controls, where GDF-15 seemed to be associated with severity of CAD. GDF-15 demonstrated a sensitivity of 84.0% and specificity of 84.8% for diagnosis of UAP, while the negative predictive value was 87.4%. The sensitivity and specificity, negative predictive value of IMA in the diagnosis of UAP were 70.0%, 69.5%, and 70.0%, respectively. PAPP-A had the lowest sensitivity and negative predictive value compared with other markers. CONCLUSIONS: GDF-15 demonstrated a significant improvement in earlier prediction and assessment of overall patient risk of UAP comparing to IMA and PAPP-A.

Proteins related to the functions of fibroblast-like synoviocytes identified by proteomic analysis.

OBJECTIVES: It is well known that the fibroblast-like synoviocytes (FLS) play a key role in pathogenesis of rheumatoid arthritis (RA). This study was performed to separate the differentially expressed proteins of FLS from the patients with RA or osteoarthritis (OA) by two-dimensional electrophoresis (2-DE), and found proteins associated with the functions of FLS by mass spectrometry (MS). METHODS: Total proteins were extracted and quantified from the primary cultured FLS from patients of RA (n=8) or OA (n=6). Proteins were separated by high-resolution 2-DE, and identified the differentially expressed proteins by MS. Western blot analyses was used to validated the expression of candidate proteins. The mRNA of these proteins was detected by semi-quantitative fluorescent PCR. RESULTS: There are 1147 protein spots from RA and 1324 protein spots from OA showed on 2-DE graphs, respectively. We have selected 84 protein spots for MS analysis, and 27 protein spots were successfully identified. We have found that protein isoaspartyl methyltransferase (PIMT) and pirin (iron-binding nuclear protein, PIR) with lower expression in RA, and thioredoxin 1(Trx-1) only expressed in RA may be associated with functions of FLS. Western Blot confirmed the expression of PIMT and pirin lower in RA, and Trx-1 expressed only in RA. The results of semi-quantitative fluorescent PCR are also consistent with 2-DE graphs. CONCLUSIONS: PIMT, pirin and Trx-1 affect the functions of FLS in some style and can be the drug targets of RA.

Diagnostic value of glucose-6-phosphate isomerase in rheumatoid arthritis.

BACKGROUND: Although glucose-6-phosphate isomerase (G6PI), anti-G6PI antibodies and G6PI-containing immune complexes (G6PI-CIC) have proved high expression in patients with rheumatoid arthritis (RA), comprehensive evaluation of the G6PI-derived markers, G6PI antigen, anti-G6PI Abs, G6PI-CIC and G6PI mRNA, in the diagnosis of RA remains necessary. METHODS: We measured G6PI antigen, anti-G6PI Abs, C1q/G6PI-CIC as well as anti-cyclic citrullinated peptide antibodies (anti-CCP Abs) in serum and concomitantly synovial fluid (SF) by ELISA in RA, other rheumatic diseases and healthy controls. The G6PI mRNA expression in peripheral blood mononuclear cells (PBMCs) was assessed with real-time PCR. RESULTS: As compared with non-RA patients, RA patients had increased levels of G6PI antigen, anti-G6PI Abs, C1q/G6PI-CIC and G6PI mRNA expression in sera or PBMCs, and increased levels of G6PI and C1q/G6PI-CIC in SF. The serum G6PI levels in RA patients positively correlated with anti-G6PI Abs, C1q/G6PI-CIC, G6PI mRNA, anti-CCP Abs, RF, CRP and ESR, respectively. The area under curve analyses demonstrated that serum G6PI had the best discriminating power for RA and active RA followed by C1q/G6PI-CIC, anti-G6PI Abs and G6PI mRNA. The simultaneous use of serum G6PI and anti-CCP Abs assays in the form of either of them tested positive gave improved sensitivities of 88.1% for RA and 95.8% for active RA. CONCLUSIONS: Despite the elevated expression of all G6PI-derived markers in RA, the serum G6PI has the best discriminating power among the four G6PI-derived markers. The serum G6PI determination either alone or in combination with anti-CCP Abs improves the diagnosis of RA.