During several months of 2003, a newly identified illness termed severe acute respiratory syndrome (SARS) spread rapidly through the world. A new coronavirus (SARS-CoV) was identified as the SARS pathogen, which triggered severe pneumonia and acute, often lethal, lung failure. Moreover, among infected individuals influenza such as the Spanish flu and the emergence of new respiratory disease viruses have caused high lethality resulting from acute lung failure. In cell lines, angiotensin-converting enzyme 2 (ACE2) has been identified as a potential SARS-CoV receptor. The high lethality of SARS-CoV infections, its enormous economic and social impact, fears of renewed outbreaks as well as the potential misuse of such viruses as biologic weapons make it paramount to understand the pathogenesis of SARS-CoV. Here we provide the first genetic proof that ACE2 is a crucial SARS-CoV receptor in vivo. SARS-CoV infections and the Spike protein of the SARS-CoV reduce ACE2 expression. Notably, injection of SARS-CoV Spike into mice worsens acute lung failure in vivo that can be attenuated by blocking the renin-angiotensin pathway. These results provide a molecular explanation why SARS-CoV infections cause severe and often lethal lung failure and suggest a rational therapy for SARS and possibly other respiratory disease viruses.

Long noncoding RNAs (lncRNAs) are emerging as important regulators in cellular processes, including the development, proliferation, and migration of cancer cells. We have demonstrated in a prior study that small nucleolar RNA host gene 5 (SNHG5) is dysregulated in gastric cancer (GC). To further explore the underlying mechanisms of SNGH5 function in the development of GC, in this study, we screened the microRNAs interacting with SNHG5 and elucidated their roles in GC. We showed that SNHG5 contains a putative miR-32-binding site and that deletion of this site abolishes the responsiveness to miR-32. Suppression of SNHG5 expression by miR-32 was found to be Argonaute (Ago)2-dependent. Immunoprecipitation showed that SNHG5 could be pulled down from the Ago-2 complex with miR-32. Furthermore, it was reported that Kruppel-like factor 4 (KLF4) is a target gene of miR-32. In agreement with SNHG5 being a decoy for miR-32, we showed that KLF4 suppression by miR-32 could be partially rescued by SNHG5 overexpression, whereas miR-32 mimic rescued SNHG5 overexpression-mediated suppression of GC cell migration. In addition, we identified a negative correlation between the expression of SNHG5 and miR-32 in GC tissues. Furthermore, KLF4 expression was significantly downregulated in GC specimens, and a negative correlation between miR-32 and KLF4 expression and a positive correlation between KLF4 and SNHG5 expression levels were detected. Overall, this study demonstrated, for the first time, that the SNHG5/miR-32/KLF4 axis functions as an important player in GC cell migration and potentially contributes to the improvement of GC diagnosis and therapy.-Zhao, L., Han, T., Li, Y., Sun, J., Zhang, S., Liu, Y., Shan, B., Zheng D., Shi, J. The lncRNA SNHG5/miR-32 axis regulates gastric cancer cell proliferation and migration by targeting KLF4.

The urinary proteome is known to be a valuable field of study related to organ functions. There have been several extensive urine proteome studies. However, the overlapping rate among different studies is relatively low. Whether the low overlapping rate was caused by different sample sources, preparation, separation and identification methods is unknown. Moreover, low molecular mass (<10 kDa) proteins have not been studied extensively. In this report, male and female pooled urine samples were collected from healthy volunteers. The urinary proteins were acetone precipitated, separated and identified by three approaches, 1-DE plus 1-D LC/MS/MS, direct 1-D LC/MS/MS and 2-D LC/MS/MS. 1-D tricine gels were used to separate low molecular mass proteins. The tandem mass spectra of positive identifications were quality controlled both by manual validation and using advanced mass spectrum scanner software. A total of 226 urinary proteins were identified; 171 proteins were identified by proteomics approach for the first time, including 4 male-specific proteins. Twelve low molecular mass proteins were identified. Most urinary proteins had a molecular mass between 30 and 60 kDa and a pI between 4 and 10. The apparent molecular masses of many proteins were different from theoretical ones, which indicated their post-translational modification and degradation. The effects of sample preparation, separation and identification methods on the overlapping rate of different experiments are discussed.

The combinations of gel electrophoresis or LC and mass spectrometry are two popular approaches for large scale protein identification. However, the throughput of both approaches is limited by the speed of the protein digestion process. Present research into fast protein enzymatic digestion has been focused mainly on known proteins, and it is unclear whether these results can be extrapolated to complex protein mixtures. In this study microwave technology was used to develop a fast protein preparation and enzymatic digestion method for protein mixtures. The protein mixtures in solution or in gel were prepared and digested by microwave-assisted protein enzymatic digestion, which rapidly produces peptide fragments. The peptide fragments were further analyzed by capillary LC and ESI-ion trap-MS or MALDI-TOF-MS. The technique was optimized using bovine serum albumin and then applied to human urinary proteins and yeast lysate. Proteomics aims to characterize a large number of proteins extracted from a cell, tissue, or organism so that a global perspective of changes in protein expression can be obtained in a rapid fashion (1, 2). Proteomic analysis of complex mixtures of proteins usually proceeds along either a bottom-up or top-down approach. In the bottom-up approach, the entire proteome is digested into a pool of possibly thousands of peptides (3-5). Two-dimensional (2D) 1 LC and MS are used to resolve and identify peptide components in the mixture. This approach, referred to as shotgun proteomics, affords the advantages of automation and sensitivity but at the loss of information regarding the intact protein.In the top-down approach, the characteristics of a protein, such as molecular weight, isoelectric point, and hydrophobicity, are used to isolate the intact protein (6, 7). Gel electrophoresis is the most commonly used top-down approach (8). Each slice or spot in the gels is excised, digested, and identified by MALDI-MS or ESI-ion trap-MS. Another top-down approach uses chromatofocusing and reverse phase chromatography in an HPLC format to separate proteins (9 -12). Each fraction from LC is also digested and identified by MS. LC offers an advantage over gel electrophoresis in terms of ease of automation and protein recovery. Although protein and peptide separation and identification can be made highly automated and rapid, sample preparation and digestion in contrast are considerably slower (more than 16 h) and limit the speed of large scale protein identification. Recently several approaches have been developed for fast protein digestion. One approach is the use of modified trypsin for in-gel digestion of proteins instead of native trypsin (13). Another approach uses on-line protein digestion during LC using a proteolytic reactor (14, 15) or an immobilized enzyme column (16,17). Other promising approaches include microwave-assisted protein enzymatic digestion (MAPED) or acid hydrolysis (18 -22).Several recent reports have highlighted the speed and convenience of MAPED. Juan et al. (18) used microwave technology ...

Recently, intriguing new roles for some small nucleolar RNA host genes (SNHGs) in cancer have emerged. In the present study, a panel of SNHGs was profiled to detect aberrantly expressed SNHGs in gastric cancer (GC). The expression of SNHG5 was significantly downregulated in GC and was significantly associated with the formation of a tumor embolus and with the tumor, node and metastasis stage. SNHG5 was a long non-coding RNA, which was a class of non-coding RNA transcripts longer than 200 nucleotides. SNHG5 suppressed GC cell proliferation and metastasis in vitro and in vivo. Furthermore, SNHG5 exerted its function through interacting with MTA2, preventing the translocation of MTA2 from the cytoplasm into the nucleus. SNHG5 overexpression led to significant increases in the acetylation levels of histone H3 and p53, indicating that SNHG5 might affect acetylation by trapping MTA2 in the cytosol, thereby interfering with the formation of the nucleosome remodeling and histone deacetylation complex. This study is the first to demonstrate that SNHG5 is a critical and powerful regulator that is involved in GC progression through trapping MTA2 in the cytosol. These results imply that SNHG5 may be a novel therapeutic target for the treatment of GC.