Comparative proteomics analysis provides new insights into the haustorium development of Taxillus chinensis (DC.) Danser

Background Loranthus (Taxillus chinensis) is an important medicinal and parasitic plant that attacks other plants for living. To reveal the mechanisms of haustorium development, we employed an iTRAQ proteomics-based approach to identify differentially abundant proteins (DAPs) of fresh seeds (CK), baby (FB), and adult haustoria (FD). Results A total of 563 and 785 DAPs were successfully quantified in the early/later developmental stage, respectively. Pathway enrichment analysis indicated that the DAPs mainly associated with metabolic pathways, ribosome, phenylpropanoid biosynthesis and photosynthesis. In the meantime, DAPs associated with phytohormone signaling pathway changed markedly. Furthermore, we evaluated the contents change of phytohormone during the haustoria development. These results indicated that phytohormone is very important for haustorium development. qRT-PCR validation showed that the mRNA expression levels were consistent with the protein variation, suggesting that our result were reliable. Conclusions To the best of our knowledge, this is the first haustoria proteomes of loranthus, and our findings will improve our understanding of the molecular mechanism of haustoria development.

Comparative iTRAQ proteomics identified proteins associated with sperm maturation between yak and cattleyak epididymis

Background During maturation, spermatozoa acquire motility and fertilizing capacity as they transit through the epididymis. In recent years, two-dimensional gel electrophoresis has been employed in proteomics studies conducted in rat, boar and human. However, there has not been a complete information regarding the proteins associated with sperm maturation in the epididymis. In this study, we employed iTRAQ proteomics to investigate proteins associated with sperm maturation between yak and cattleyak epididymis. Results After a successful sampling and protein extraction, the iTRAQ coupled with LC-MS/MS mass spectrometry and bioinformatics analysis were performed. We identified 288 differentially abundant proteins (DAPs) between yak and cattleyak epididymis; 151 were up-regulated while 137 were down-regulated in cattleyak relative to yak. Gene Ontology analysis identified that down-regulated DAPs in cattleyak were mostly enriched in the acetylation of protein component, along with negative and positive regulatory activities. iTRAQ proteomics data showed that the top up-regulated DAPs were mainly enriched in cell communication, cell adhesion, cytoskeleton organization, stress response, post-translational modifications and metabolic functions while the down-regulated DAPs were predominantly associated with sperm maturation, long-term sperm storage, sperm forward motility, sperm-oocyte fusion and regulatory functions. Conclusion These results provide insight into the molecular mechanisms underlying male cattleyak sterility.

Identification of targets of JS-K against HBV-positive human hepatocellular carcinoma HepG2.2.15 cells with iTRAQ proteomics

JS-K, a nitric oxide-releasing diazeniumdiolates, is effective against various tumors. We have discovered that JS-K was effective against Hepatitis B virus (HBV)-positive HepG2.2.15 cells. This study used iTRAQ to identify differentially expressed proteins following JS-K treatment of HepG2.2.15 cells. Silenced Transgelin (shTAGLN-2.15) cells were constructed, and the cell viability was analyzed by the CCK8 assay after treatment with JS-K. There were 182 differentially expressed proteins in JS-K treated-HepG2.2.15 cells; 73 proteins were up-regulated and 109 proteins were down-regulated. These proteins were categorized according to GO classification. KEGG enrichment analysis showed that Endocytosis, Phagosome and Proteoglycans were the most significant pathways. RT-PCR confirmed that the expression levels of TAGLN, IGFBP1, SMTN, SERPINE1, ANXA3, TMSB10, LGALS1 and KRT19 were significantly up-regulated, and the expression levels of C5, RBP4, CHKA, SIRT5 and TRIM14 were significantly down-regulated in JS-K treated-HepG2.2.15 cells. Western blotting confirmed the increased levels of USP13 and TAGLN proteins in JS-K treated-HepG2.2.15 cells. Molecular docking revealed the binding of JS-K to TAGLN and shTAGLN-2.15 cells were resistant to JS-K cytotoxicity, suggesting that TAGLN could be an important target in JS-K anti-HBV-positive liver cancer cells. These proteomic findings could shed new insights into mechanisms underlying the effect of JS-K against HBV-related HCC.

Elevated Serum FGG Levels Prognosticate and Promote the Disease Progression in Prostate Cancer

Castration-resistant prostate cancer (CRPC) threatens the health of men in general and no effective therapeutics currently exists for the treatment of CRPC. It is therefore of great importance to find a novel molecule that can be a biomarker and a therapeutic target for CRPC. First, we found that the serum fibrinogen gamma (FGG) levels in patients with CRPC were significantly higher than those with localized prostate cancer (PCa) through iTRAQ proteomics and ELISA experiments. Immunohistochemistry, quantitative real-time polymerase chain reaction and western blot also showed an increase of FGG expression in CRPC tissues and cells. Then we proved the proliferation, invasion and migration ability of CRPC cells were significantly reduced after FGG knockdown. The number of apoptotic cells increased at least sixfold after FGG silencing, and was observed in conjunction with an upregulation of p53, caspase 3, clea-caspase 3, and Bax, and a downregulation of Bcl2 and survivin. FGG knockdown in DU145 cells resulted in smaller xenografts than control cells in a mouse model. and we established that FGG is modulated by IL-6 which was increased in CRPC patients via phosphorylation of STAT3. The data suggests that FGG may be a potential therapeutic target and prognostic marker for CRPC.

Combination of RNA-Seq transcriptomics and iTRAQ proteomics reveal the mechanism involved in fresh-cut yam yellowing

The aim of this study was to examine the regulation of transcriptomics and proteomics related to the yellowing of fresh-cut yams after storage. The comparison of yellow fresh-cut yam (YFY) vs. white fresh-cut yam (control) revealed 6894 upregulated and 6800 downregulated differentially expressed genes along with 1277 upregulated and 677 downregulated differentially expressed proteins. The results showed that the total carotenoids, flavonoids, and bisdemethoxycurcumin in YFY were higher than in the control due to the significant up-regulation of critical genes in the carotenoid biosynthesis pathway, flavonoid biosynthesis pathway, and stilbenoid, diarylheptanoid, and gingerol biosynthesis pathway. In addition, the tricarboxylic acid cycle and phenylpropanoid biosynthesis were both enhanced in YFY compared to the control, providing energy and precursors for the formation of yellow pigments. The results suggest that the synthesis of yellow pigments is regulated by critical genes, which might explain the yellowing of fresh-cut yam after storage.

iTRAQ-based proteomic profiling reveals protein alterations after traumatic brain injury and supports thyroxine as a potential treatment

Traumatic brain injury (TBI) is a primary cause of disability and death across the world. Previously, RNA analysis was widely used to study the pathophysiological mechanisms underlying TBI; however, the relatively low correlation between the transcriptome and proteome revealed that RNA transcription abundance does not reliably predict protein abundance, which led to the emergence of proteomic research. In this study, an iTRAQ proteomics approach was applied to detect protein alterations after TBI on a large scale. A total of 3937 proteins were identified, and 146 proteins were significantly changed after TBI. Moreover, 23 upregulated proteins were verified by parallel reaction monitoring (PRM), and fold changes in 16 proteins were consistent with iTRAQ outcomes. Transthyretin (Ttr) upregulation has been demonstrated at the transcriptional level, and this study further confirmed this at the protein level. After treatment with thyroxine (T4), which is transported by Ttr, the effects of T4 on neuronal histopathology and behavioral performance were determined in vivo (TBI + T4 group). Brain edema was alleviated, and the integrity of the blood brain barrier (BBB) improved. Escape latency in the Morris water maze (MWM) declined significantly compared with the group without T4 treatment. Modified neurological severity scores (mNSS) of the TBI + T4 group decreased from day 1 to day 7 post-TBI compared with the TBI + saline group. These results indicate that T4 treatment has potential to alleviate pathologic and behavioral abnormalities post-TBI. Protein alterations after T4 treatment were also detected by iTRAQ proteomics. Upregulation of proteins like Lgals3, Gfap and Apoe after TBI were reversed by T4 treatment. GO enrichment showed T4 mainly affected intermediate filament organization, cholesterol transportation and axonal regeneration. In summary, iTRAQ proteomics provides information about the impact of TBI on protein alterations and yields insight into underlying mechanisms and pathways involved in TBI and T4 treatment. Finally, Ttr and other proteins identified by iTRAQ may become potential novel treatment targets post-TBI.