ABSTRACT
Sepsis， a common critical disease in the intensive care unit（ICU）， features high morbidity and mortality. At present， it is mainly tackled with western medicine， which may trigger a series of problems like antibiotic resistance， adverse hormonal reactions， and high cost after a long-term use. Therefore， exploring new efficient， safe， and cheap drugs and treatment modes has become the focus of our research at this stage. By virtue of unique advantages including "the concept of holism and individualized treatment based on syndrome differentiation"， Chinese medicine has accumulated quite rich experience in the prevention and treatment of sepsis. In recent years， research on the regulation of Chinese medicine on nuclear transcription factor-κB（NF-κB） signaling pathway in sepsis has kept emerging. On this basis， this paper reviewed the etiology and pathogenesis of sepsis， syndrome differentiation and treatment， NF-κB signaling pathway， and its intervention with Chinese medicine. It has been found that some single Chinese herbs and their extracts， Chinese herbal compounds， and Chinese herbal injections effectively inhibit the expression of such inflammatory factors as NF-κB-mediated tumor necrosis factor-α（TNF-α）， interleukin-1（IL-1）， and IL-6 as well as the related proteins， reduce the systemic inflammatory response and organ injury， and improve the prognosis by regulating the activation of NF-κB signaling pathway and the immune function of macrophages. However， due to the limitations of objective conditions， some studies also have the problems of fuzzy pro-inflammatory anti-inflammatory balance mechanism， unclear pharmacokinetics and low drug safety evaluation， which need to be further studied and explored in order to provide a new theoretical basis and diagnosis and treatment thinking for the treatment of sepsis with traditional Chinese medicine.
ABSTRACT
<p><b>BACKGROUND</b>The rapid transmission and high mortality rate made severe acute respiratory syndrome (SARS) a global threat for which no efficacious therapy is available now. Without sufficient knowledge about the SARS coronavirus (SARS-CoV), it is impossible to define the candidate for the anti-SARS targets. The putative non-structural protein 2 (nsp2) (3CL(pro), following the nomenclature by Gao et al, also known as nsp5 in Snidjer et al) of SARS-CoV plays an important role in viral transcription and replication, and is an attractive target for anti-SARS drug development, so we carried on this study to have an insight into putative polymerase nsp2 of SARS-CoV Guangdong (GD) strain.</p><p><b>METHODS</b>The SARS-CoV strain was isolated from a SARS patient in Guangdong, China, and cultured in Vero E6 cells. The nsp2 gene was amplified by reverse transcription-polymerase chain reaction (RT-PCR) and cloned into eukaryotic expression vector pCI-neo (pCI-neo/nsp2). Then the recombinant eukaryotic expression vector pCI-neo/nsp2 was transfected into COS-7 cells using lipofectin reagent to express the nsp2 protein. The expressive protein of SARS-CoV nsp2 was analyzed by 7% sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE). The nucleotide sequence and protein sequence of GD nsp2 were compared with that of other SARS-CoV strains by nucleotide-nucleotide basic local alignment search tool (BLASTN) and protein-protein basic local alignment search tool (BLASTP) to investigate its variance trend during the transmission. The secondary structure of GD strain and that of other strains were predicted by Garnier-Osguthorpe-Robson (GOR) Secondary Structure Prediction. Three-dimensional-PSSM Protein Fold Recognition (Threading) Server was employed to construct the three-dimensional model of the nsp2 protein.</p><p><b>RESULTS</b>The putative polymerase nsp2 gene of GD strain was amplified by RT-PCR. The eukaryotic expression vector (pCI-neo/nsp2) was constructed and expressed the protein in COS-7 cells successfully. The result of sequencing and sequence comparison with other SARS-CoV strains showed that nsp2 gene was relatively conservative during the transmission and total five base sites mutated in about 100 strains investigated, three of which in the early and middle phases caused synonymous mutation, and another two base sites variation in the late phase resulted in the amino acid substitutions and secondary structure changes. The three-dimensional structure of the nsp2 protein was successfully constructed.</p><p><b>CONCLUSIONS</b>The results suggest that polymerase nsp2 is relatively stable during the phase of epidemic. The amino acid and secondary structure change may be important for viral infection. The fact that majority of single nucleotide variations (SNVs) are predicted to cause synonymous, as well as the result of low mutation rate of nsp2 gene in the epidemic variations, indicates that the nsp2 is conservative and could be a target for anti-SARS drugs. The three-dimensional structure result indicates that the nsp2 protein of GD strain is high homologous with 3CL(pro) of SARS-CoV urbani strain, 3CL(pro) of transmissible gastroenteritis virus and 3CL(pro) of human coronavirus 229E strain, which further suggests that nsp2 protein of GD strain possesses the activity of 3CL(pro).</p>