Differential expression of pepsinogen isozymogens in a patient with Barrett esophagus

Microarray expression profile analysis of mRNAs and long non-coding RNAs in pulmonary tuberculosis with different traditional Chinese medicine syndromes

Background

Combination chemotherapy with Western anti-tuberculosis (TB) drugs is the mainstay of TB treatment. Chinese herbal medicines with either heat clearing and detoxifying effects or nourishing Yin and reducing fire effects have been used to treat TB based on the Traditional Chinese Medicine (TCM) syndromes of TB patients. This study analyzed the expression profiles of long non-coding RNAs (lncRNAs) and mRNAs in TB patients with different TCM syndromes.

Methods

TB patients were classified as pulmonary Yin deficiency (PYD) syndrome, hyperactivity of fire due to Yin deficiency (HFYD) syndrome, and deficiency of Qi and Yin (DQY) syndrome. Total RNA from 44 TB patients and healthy controls was extracted and hybridized with a human lncRNA microarray containing 30586 lncRNAs and 26109 mRNAs probes. Bioinformatics analyses, including gene ontology (GO) and pathways, were performed. Related clinical data were also analyzed.

Results

Differentially expressed mRNAs and lncRNAs were identified (fold change >2, and P < 0.05) in PYD (634 mRNAs and 566 lncRNAs), HFYD (47 mRNAs and 55 lncRNAs), and DQY (63 mRNAs and 60 lncRNAs) patients. The most enriched pathways were the hippo signaling pathway (P = 0.000164) and the protein digestion and absorption pathway (P = 5.89017E-05). Clinical analyses revealed that the lipid indexes of TB patients were abnormal and that the triglyceride concentration was significantly higher in DQY patients (P = 0.0252). Our study is the first to acquire the microarray expression profiles of lncRNAs and mRNAs and analyze pathway enrichment in PYD, HFYD, and DQY patients with TB.

Conclusions

Our analyses of the expression profiles of lncRNAs and mRNAs may represent a novel method to explore the biological essence of TCM syndromes of TB.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-016-1436-y) contains supplementary material, which is available to authorized users.

Local Synthesis of Pepsin in Barrett's Esophagus and the Role of Pepsin in Esophageal Adenocarcinoma

OBJECTIVE

Despite widespread use of proton pump inhibitors (PPIs), the incidence of esophageal adenocarcinoma (EAC) continues to rise. PPIs reduce reflux acidity, but only transiently inactivate gastric enzymes. Nonacid reflux, specifically nonacid pepsin, contributes to carcinogenesis in the larynx. Given the carcinogenic potential of pepsin and inefficacy of PPIs to prevent EAC, the presence and effect of pepsin in the esophagus should be investigated.

METHODS

Normal and Barrett's biopsies from 8 Barrett's esophagus patients were collected for pepsin analysis via Western blot and reverse transcriptase-polymerase chain reaction (RT-PCR). Human esophageal cells cultured from healthy patients were treated with pepsin (0.01-1 mg/mL; 1-20 hours), acid (pH 4)±pepsin (5 minutes); real-time RT-PCR, ELISA, and cell migration were assayed.

RESULTS

Pepsin was detected in all 8 Barrett's and 4 of 8 adjacent normal specimens. Pepsinogen mRNA was observed in 22 Barrett's, but not in normal adjacent samples. Pepsin induced PTSG2 (COX-2) and IL-1β expression and cell migration in vitro.

CONCLUSIONS

Pepsin is synthesized by metaplastic, Barrett's esophageal mucosa. Nonacid pepsin increases metrics of tumorigenicity in esophageal epithelial cells in vitro. These findings implicate refluxed and locally synthesized pepsin in development and progression of EAC and, in part, explain the inefficacy of PPIs in the prevention of EAC.

Progastriscin: structure, function, and its role in tumor progression

Progastricsin (PGC) is a major seminal plasma protein having aspartyl proteinases-like activity and showing close sequence similarity to pepsins. PGC is also present as zymogen in gastric mucosa. In this article, we have reviewed all important features of PGC. Furthermore, we have compared all features of PGC with those of different aspartyl proteinases. The complete amino acid sequence of PGC reveals that it is composed of 374 residues (gastricsin moiety of 331 residues and the activation segment of 43 residues). The gene of human PGC is located at single locus on chromosome 6, whereas the human pepsinogen genetic locus is polymorphic and codes for at least three distinct polypeptide sequences on chromosome 11. The major useful function of PGC includes production of pro-antimicrobial substance in seminal plasma. The crystal structure of human PGC is known, which shows that it is quite similar to that of porcine pepsinogen. The tertiary structure of PGC is comprised of commonly bilobal structure with a large active-site cleft between the lobes. Two aspartate residues in the center of the cleft, namely Asp32 and Asp215, function as catalytic residues. The sequence and structural features of PGC indicate that it is diverged from its pepsinogen ancestor in the early phase of the evolution of gastric aspartyl proteinases. Our detailed review of PGC structure, function and activation mechanism will also be of interest to cancer biologists as well as gastroenterologists.

High-performance liquid chromatography: purification and chromatographic behaviour of molecular variants of pepsinogen A from human urine

By combining conventional DEAE chromatography with high-performance liquid chromatography on Sephacryl S-200 HR and Mono-Q columns, we have been able to isolate and fractionate human pepsinogen A (PGA) isozymogens from large amounts of urine. This method of fractionation is simple and allows one to obtain pepsinogen in a native non-denatured conformation. The isozymogens are homogeneous by electrophoretic and chromatographic criteria; this was confirmed by N-terminal amino acid sequencing. Purified PGA-3 and PGA-5 can be converted into an additional, more anionic, isoform on incubation at 37 degrees C. This isoform exists not only in vitro but also in vivo. The net negative charge of the PGA isozymogens is in the order PGA-5 less than deamidated PGA-5 less than PGA-3 less than deamidated PGA-3. Surprisingly, the elution order on the Mono-Q column was PGA-5/PGA-3/deamidated PGA-5/deamidated PGA-3. We have performed molecular modelling on PGA to investigate this phenomenon in terms of surface charge (not net charge) of the proteins. The model provides evidence that (1) only a fraction of the protein surface interacts with the support and (2) regions of localized charge at the protein surface may allow portions of the external surface to dominate chromatographic behaviour, resulting in a steering of the proteins with respect to the oppositely charged matrix. Pepsinogens may serve as model proteins for elucidating some of the variables that determine the chromatographic behaviour of proteins on ion-exchange columns.

Human pepsinogen C (progastricsin) polymorphism: evidence for a single locus located at 6p21.1-pter

A series of six clones containing the entire human pepsinogen C gene (PGC) was identified in a cosmid vector library by using cDNA and oligonucleotide probes. The 10.7-kb PGC gene includes nine exons and exhibits a high degree of sequence identity (60%) with the functionally related pepsinogen A genes. The predicted amino acid sequence was identical with the partial amino-terminal and carboxyl-terminal sequences of purified pepsinogen C. An informative restriction fragment length polymorphism was detected with several restriction enzymes and involved an insertion or deletion of 100 bp of intron sequence located between exons 7 and 8. Evidence that there is only a single PGC gene in humans is presented. The PGC gene and the prolactin gene were regionally localized to 6p21.1-pter by analysis of mouse X human somatic cell hybrids.