Enantioselective Synthesis of Chiral Organosilicon Compounds by Organocatalytic Asymmetric Conjugate Addition of Boronic Acids to ß-Silyl-α,ß-Unsaturated Ketones.

Herein, we report (R)-3,3'-(3,5-(CF3)2-C6H3)2-BINOL-catalyzed enantioselective conjugate addition of organic boronic acids to ß-silyl-α,ß-unsaturated ketones, furnishing moderate to excellent yields of the corresponding ß-silyl carbonyl compounds with stereogenic centers in excellent enantioselectivities (up to 98% ee). Moreover, the catalytic system features mild reaction conditions, high efficiency, broad substrate scope, and easy scale-up.

Guidelines on the treatment with integrated traditional Chinese medicine and western medicine for severe coronavirus disease 2019.

Severe Coronavirus Disease 2019 (COVID-19) is characterized by numerous complications, complex disease, and high mortality, making its treatment a top priority in the treatment of COVID-19. Integrated traditional Chinese medicine (TCM) and western medicine played an important role in the prevention, treatment, and rehabilitation of COVID-19 during the epidemic. However, currently there are no evidence-based guidelines for the integrated treatment of severe COVID-19 with TCM and western medicine. Therefore, it is important to develop an evidence-based guideline on the treatment of severe COVID-19 with integrated TCM and western medicine, in order to provide clinical guidance and decision basis for healthcare professionals, public health personnel, and scientific researchers involved in the diagnosis, treatment, and care of COVID-19 patients. We developed and completed the guideline by referring to the standardization process of the "WHO handbook for guideline development", the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system, and the Reporting Items for Practice Guidelines in Healthcare (RIGHT).

Development of genetically engineered iNKT cells expressing TCRs specific for the M. tuberculosis 38-kDa antigen.

INTRODUCTION: The invariant natural killer T (iNKT) cell has been shown to play a central role in early stages immune responses against Mycobacterium tuberculosis (Mtb) infection, which become nonresponsive (anergic) and fails to control the growth of Mtb in patients with active tuberculosis. Enhancement of iNKT cell responses to Mtb antigens can help to resist infection. STUDY DESIGN AND METHODS: In the present study, an Mtb 38-kDa antigen-specific T cell receptor (TCR) was isolated from human CD8(+) T cells stimulated by 38-kDa antigen in vitro, and then transduced into primary iNKT cells by retrovirus vector. RESULTS: The TCR gene-modified iNKT cells are endowed with new features to behave as a conventional MHC class I restricted CD8(+) T lymphocyte by displaying specific antigen recognition and anti-Mtb antigen activity in vitro. At the same time, the engineered iNKT cells retaining its original capacity to be stimulated proliferation by non-protein antigens α-Gal-Cer. CONCLUSIONS: This work is the first attempt to engineer iNKT cells by exogenous TCR genes and demonstrated that iNKT cell, as well as CD4(+) and CD8(+) T cells, can be genetically engineered to confer them a defined and alternative specificity, which provides new insights into TCR gene therapy for tuberculosis patients, especially those infected with drug-resistant Mtb.

Normalization of T cell receptor repertoire diversity in patients with advanced colorectal cancer who responded to chemotherapy.

To investigate the correlation between normalization of T cell receptor (TCR) repertoire and remission of advanced colorectal cancer. Forty-one patients were randomly assigned to receive either folinic acid/fluorouracil/irinotecan alone (n = 20) or folinic acid/fluorouracil/irinotecan in combination with recombinant human endostatin (n = 21). Efficacy and toxicity were evaluated, and changes in TCR repertoire diversity were assessed by detecting the spectratypes of TCR complementarity-determining region three before and after several cycles of therapy. A scoring system was used to quantify changes in the TCR repertoire over time. The results demonstrated that the TCR repertoire exhibited a higher degree of normalization among patients undergoing remission relative to patients experiencing tumor progression. The results of the current study showed a positive correlation between TCR repertoire normalization and remission of colorectal cancer, suggesting that dynamic monitoring of TCR repertoire diversity may have potential prognostic value in the clinical setting.

Cancer of the gastrointestinal tract results in a restricted T-cell repertoire dependent upon tumor differentiation.

We investigated the influence of tumor tissue differentiation on the diversity of TCR repertoire. CDR3 spectratypes of CD4(+) and CD8(+) T cell subsets were analyzed from 27 patients with gastrointestinal tract tumors exhibiting varying degrees of differentiation. A CDR3 spectratype complexity scoring system was used to quantify the diversity of TCR repertoire. Each patient was matched with an age-matched healthy group to control for age variability. Results show that the complexity scores (TCR repertoire diversity) have a significant correlation with the degree of tumor differentiation, which provides useful information for understanding immune response in cancer patients.

Polysaccharide from Phellinus Igniarius activates TLR4-mediated signaling pathways in macrophages and shows immune adjuvant activity in mice.

Polysaccharide from Phellinus igniarius (PPI) is known for its immune-regulating effect with low toxicity. Toll like receptor 4 (TLR4) is important in both innate and adaptive immune responses and considered to be a promising target for new immune adjuvants. In this study, PPI was investigated for its effect on activating TLR4 in RAW264.7 and peritoneal macrophages. The adjuvant potential of PPI was evaluated in OVA-immunized mice. The results showed PPI treatment significantly increased the secretion and the mRNA expression of both MyD88 dependent and TRIF dependent cytokines. IRAK-1, a key molecule on the downstream of MyD88, was polyubiquitinated while IRF-3, another key molecule on the downstream of TRIF, was phosphorylated obviously after the treatment of PPI. The phosphorylation of molecules involved in both NF-κB pathway and MAPK pathway were significantly up-regulated after PPI treatment. In addition, the effects of PPI on the macrophages almost completely disappeared after treating the cells with the TLR4 antagonist TAK-242. Further in vivo results showed PPI significantly increased the serum OVA-specific antibody and the OVA-specific spleen cell proliferation. Taken together, PPI can specifically stimulate TLR4 and activate both MyD88 and TRIF pathways. PPI has immune adjuvant activity and may become a new potential immune adjuvant.

Comparison of four methods for the purification and refolding of human interleukin-2-mouse granulocyte/macrophage colony-stimulating factor fusion protein.

The combination of IL-2 (interleukin-2) and GM-CSF (granulocyte/macrophage colony-stimulating factor) has been broadly studied in antitumour immune therapy, but its efficacy is uncertain. To better exert the activities of the two cytokines and study them in a mouse model, we have constructed a bifunctional protein, hIL-2-mGM-CSF (human IL-2-mouse GM-CSF), fused to a C-terminal tag of six histidine residues (His(6)). The fusion protein was expressed in Escherichia coli as IBs (inclusion bodies). After extracting and clarifying the IBs, four methods of protein purification and refolding were compared in order to optimize the preparation technique. Of these methods, the best result was obtained with a four-step process consisting of (1) purification with denaturing affinity chromatography, (2) followed by fully denaturing the protein with system conversion, (3) then refolding by isovolumetric ultrafiltration and (4) finally, purification by anion-exchange chromatography. The purity of the hIL-2-mGM-CSF was approx. 95%, yielding approx. 20 mg of protein/l of culture. The fusion protein retained the natural activities of IL-2 and GM-CSF, with specific activities of 8.7 x 10(6) and 1.1 x 10(7) i.u./mg respectively. Flow-cytometric analysis indicated that hIL-2-mGM-CSF could specifically bind to the corresponding receptor-positive cells. The present study provides important preliminary information for studying the antitumour activity of hIL-2-mGM-CSF in vivo, which will facilitate future clinical research into the use of hIL-2/hGM-CSF in immune therapy.

A modified peptide stimulation method for efficient amplification of cytomegalovirus (CMV)-specific CTLs.

CMV-specific immunity is essential for control of human cytomegalovirus (HCMV) infection. Stem cell transplantation is used widely in the management of a range of diseases of the hemopoietic system. Patients are immunosuppressed profoundly in the early posttransplant period, and reactivation of cytomegalovirus (CMV) remains a significant cause of morbidity and mortality. Adoptive transfer of CMV-specific CD8+ T cell clones has been shown to reduce the rate of viral reactivation; however, the ex vivo production of cells for adoptive transfer is labor intensive and expensive. We report here a modified peptide stimulation method using CMV-specific epitope peptides to stimulate PBMCs for generation of CMV-specific CTLs. This method permits efficient amplification of CMV-specific CTLs and provides a large number of cells for FACS analysis from a single blood sample. Significantly, it achieves high frequencies of tetramer staining of CD8+ T cells allowing the data of different individuals to be easily compared and sequentially evaluated. Thus, this approach expands and selects HLA-restricted CMV-pp65-reactive T-cell lines of high specificity for potential adoptive immunotherapy.

Expression, purification, and refolding of recombinant fusion protein hIL-2/mGM-CSF.

OBJECTIVE: To study the activities of interleukin (IL)-2 and granulocyte-macrophage colony-stimulating factor (GM-CSF) (hIL-2/mGM-CSF). METHODS: SOE PCR was used to change the linker of the fusion protein for higher activities. The fusion protein was expressed in Escherichia coli (E. coli) BL21 (DE3) in inclusion body (IB) form. After IB was extracted and clarified, it was denatured and purified by affinity chromatography. The protein was refolded by dilution in a L-arginine refolding buffer and refined by anion chromatography. The protein activity was detected by cytokine-dependent cell proliferation assay. RESULTS: The expression of hIL-2/mGM-CSF in E. coli yielded approximately 20 mg protein /L culture and the purity was about 90%. The specific activities of IL-2 and GM-CSF were 5.4 x 10(6) IU/mg and 7.1 x 10(6) IU/mg, respectively. CONCLUSION: This research provides important information about the anti-tumor activity of hIL-2/mGM-CSF in vivo, thus facilitating future clinical research on hIL-2/mGM-CSF used in immune therapy.

[High cell density fed-batch culture of E.coli expressing rhVEGF121].

OBJECTIVE: To investigate the optimal high cell density fermentation conditions of recombinant E.coli BL21/pET- 24a/hVEGF(121) expressing recombinant human vascular endothelial growth factor (rhVEGF(121)). METHODS: The effects of the composition of the fermentation medium, induction time and fed-batch carbon sources on the expression level of rhVEGF(121) and cell output were analyzed. RESULTS AND CONCLUSION: When cultured in modified M9 medium and induced for 4 h in the presence of 0.5 mmol/L IPTG at 37 degrees celsius; with glycerol as the carbon sources by continuous fed-batch mode, the recombinant E.coli expressed rhVEGF(121) at the level up to 23% of the total proteins and the yield reached 68 g/L. The optimized fermentation condition for recombinant E.coli enables high expression level of rhVEGF(121).

[Emperipolesis of pre-stimulated lymphocytes].

OBJECTIVE: To describe the emperipolesis of lymphocytes and investigate the factors affecting lymphocyte emperipolesis in the KB cells and the relation of the emperipolesis to the biological behaviors of the lymphocytes. METHODS: After pre-stimulation with phytohemagglutinin (PHA), interleukin (IL)-2, a-CD3, and PHA+IL-2, respectively, the peripheral blood lymphocytes (PBLs) isolated from healthy donors were mixed with KB cells to observe the emperipolesis of the PBLs under inverted microscope every other hour, and calculate the tumor-adhesion/emperipolesis indices of the PBLs. The cell mixture was then fixed with cool acetone and stained by Giemasa to observe emperipolesis between PBLs and KB cells. The occurrence and development of emperipolesis between PBLs and KB cells was also observed under scanning electron microscope (SEM) at 1, 2, 4, and 6 hours after fixation. RESULTS: The tumor-adhesion/emperipolesis indices of pre-stimulated PBLs were significantly higher than those of non-stimulated PBLs, and the indices of PHA+IL-2 group were the highest. The PBLs underwent morphological changes in the course of PBL emperipolesis mixed with KB cells as observed under SEM. CONCLUSION: Pre-stimulation can enhance the tumor-adhesion/emperipolesis indices of the PBLs. The emperipolesis might be a means of cytotoxicity of the PBLs.

[Preparation and identification of egg yolk antibodies against HLA-A* 0201 heavy chain].

OBJECTIVE: To prepare a high-titer specific and efficient egg yolk immunoglobulin (IgY). METHODS: The antigen of HLA-A* 0201 heavy chain was used to immunize the hens together with Freud's adjuvant and the eggs these hens laid were collected. IgY was purified from the egg yolk by water extraction, salt precipitation with ammonium sulfate and dialysis. The immunoactivity of the IgY was measured by enzyme-linked immunosorbent assay (ELISA) and its purity was determined by SDS-PAGE. RESULTS: The titer of IgY was 1 10(6) as shown by ELISA, with protein concentration of 9.77 mg/ml. The purity of the resultant IgY was more than 90% as suggested by SDS-PAGE analysis. CONCLUSIONS: The antigen of HLA-A* 0201 heavy chain along with complete Freund adjuvant is effective to elicit an immune response of hens for producing IgY antibodies in high yields.

[Role of intron and 5' untranslated region in human thrombopoietin gene expression].

OBJECTIVE: To study the role of 5' untranslated region (UTR) and intron in the expression of human thrombopoietin (TPO) gene. METHODS: A number of expression vectors containing TPO mini-gene fused to the regulatory elements of cytomegalovirus (CMV) were constructed and transfected via lipofectin into cultured cos-1 cells for transient expression of TPO gene. The cell culture media were analyzed with highly sensitive sandwich enzyme-linked immunosorbent assay (ELISA) 48 h after the transfection. RESULTS: The expression levels of the TPO gene elements followed the order of TPO intron v> TPOcDNA> TPO intron I> TPO intron I> TPO gDNA in cos-1 cells. CONCLUSION: The last intron of TPO gene obviously enhances the expression level of TPO gene, which can be inhibited by 5'UTR of TPO gene.

[Purification and renaturation of recombinant human interleukin-2-pseudomonas exotoxin (IL2-PE66(4GLU)) fusion protein].

OBJECTIVE: To evaluate the effect of a novel approach for purification and renaturation of recombinant human interleukin-2-pseudomonas exotoxin (IL2-PE66(4Glu)) fusion protein. METHODS: A novel purification method established in our laboratory was adopted for the purification of the inclusion body, and after renaturation, recombinant human IL2-PE66(4Glu) fusion protein was purified by DEAE-Sepharose FF ion-exchange chromatography. RESULTS: The purity of the fusion protein that retain its biological activity was as high as 95%, and a recovery rate over 80% of the refolded IL2-PE66(4Glu) fusion protein was achieved. CONCLUSION: The purification and refolding method for inclusion body adopted in this study is simple and practical, which lays the foundation for a large-scale production of the fusion protein.

Cloning and sequence analysis of cDNA and genomic DNA of human thrombopoietin gene.

OBJECTIVE: To study the role of thrombopoietin (TPO) gene 5' untranslated region (UTR) and the intron in TPO expression regulation. METHODS: With the mRNA derived from Chinese human fetal liver as the template, full-length TPO cDNA (approximately 1.1 kb) and TPO genomic DNA(6.2 kb) along with all the introns of TPO gene were isolated by PCR and long-distance PCR techniques from Chinese fetal liver tissue. RESULT: Sequencing analysis indicated that all the coding sequences and the exon/intron splice sites were consistent with the results previously reported by Sohma et al except for only a DNA and all the introns in the intron of TPO gene. CONCLUSION: We have successfully cloned full-length TPO cDNA, TPO genomic DNA and all the introns of TPO gene from Chinese fetal liver tissue.

HGF-transgenic MSCs can improve the effects of tissue self-repair in a rabbit model of traumatic osteonecrosis of the femoral head.

BACKGROUND: Osteonecrosis of the femoral head (ONFH) is generally characterized as an irreversible disease and tends to cause permanent disability. Therefore, understanding the pathogenesis and molecular mechanisms of ONFH and developing effective therapeutic methods is critical for slowing the progress of the disease. METHODOLOGY/PRINCIPAL FINDINGS: In this study, an experimental rabbit model of early stage traumatic ONFH was established, validated, and used for an evaluation of therapy. Computed tomography (CT) and magnetic resonance (MR) imaging confirmed that this model represents clinical Association Research Circulation Osseous (ARCO) phase I or II ONFH, which was also confirmed by the presence of significant tissue damage in osseous tissue and vasculature. Pathological examination detected obvious self-repair of bone tissue up to 2 weeks after trauma, as indicated by revascularization (marked by CD105) and expression of collagen type I (Col I), osteocalcin, and proliferating cell nuclear antigen. Transplantation of hepatocyte growth factor (HGF)-transgenic mesenchymal stem cells (MSCs) 1 week after trauma promoted recovery from ONFH, as evidenced by a reversed pattern of Col I expression compared with animals receiving no therapeutic treatment, as well as increased expression of vascular endothelial growth factor. CONCLUSIONS/SIGNIFICANCE: These results indicate that the transplantation of HGF-transgenic MSCs is a promising method for the treatment for ONFH and suggest that appropriate interference therapy during the tissue self-repair stage contributes to the positive outcomes. This study also provides a model for the further study of the ONFH etiology and therapeutic interventions.

Limited T cell receptor repertoire diversity in tuberculosis patients correlates with clinical severity.

BACKGROUND: The importance of CD4⁺ and CD8⁺ T cells in protection against tuberculosis (TB) is well known, however, the association between changes to the T cell repertoire and disease presentation has never been analyzed. Characterization of T-cells in TB patients in previous study only analyzed the TCR ß chain and omitted analysis of the Vα family even though α chain also contribute to antigen recognition. Furthermore, limited information is available regarding the heterogeneity compartment and overall function of the T cells in TB patients as well as the common TCR structural features of Mtb antigen specific T cells among the vast numbers of TB patients. METHODOLOGY/PRINCIPAL FINDINGS: CDR3 spectratypes of CD4⁺ and CD8⁺ T cells were analyzed from 86 patients with TB exhibiting differing degrees of disease severity, and CDR3 spectratype complexity scoring system was used to characterize TCR repertoire diversity. TB patients with history of other chronic disease and other bacterial or viral infections were excluded for the study to decrease the likely contribution of TCRs specific to non-TB antigens as far as possible. Each patient was age-matched with a healthy donor group to control for age variability. Results showed that healthy controls had a normally diversified TCR repertoire while TB patients represented with restricted TCR repertoire. Patients with mild disease had the highest diversity of TCR repertoire while severely infected patients had the lowest, which suggest TCR repertoire diversity inversely correlates with disease severity. In addition, TB patients showed preferred usage of certain TCR types and have a bias in the usage of variable (V) and joining (J) gene segments and N nucleotide insertions. CONCLUSIONS/SIGNIFICANCE: Results from this study promote a better knowledge about the public characteristics of T cells among TB patients and provides new insight into the TCR repertoire associated with clinic presentation in TB patients.

Development of genetically engineered CD4+ and CD8+ T cells expressing TCRs specific for a M. tuberculosis 38-kDa antigen.

Cell-mediated immunity is critical to the clearance of Mycobacterium tuberculosis due to the primarily intracellular niche of this pathogen. Adoptive transfer of M. tuberculosis-specific effector T cells has been shown to confer immunity to M. tuberculosis-infected recipients resulting in M. tuberculosis clearance. However, it is difficult to generate sufficient numbers of M. tuberculosis antigen-specific T cells in a short time. Recent studies have developed T cell receptor (TCR) gene-modified T cells that allow for the rapid generation of large numbers of antigen-specific T cells. Many TCRs that target various tumor and viral antigens have now been isolated and shown to have functional activity. Nevertheless, TCRs specific for intracellular bacterial antigens (including M. tuberculosis antigens) have yet to be isolated and their functionality confirmed. We isolated M. tuberculosis 38-kDa antigen-specific HLA class I and class II-restricted TCRs and modified the TCR gene C regions by substituting nine amino acids with their murine TCR homologs (minimal murinization). Results showed that both wild-type and minimal murinized TCR genes were successfully cloned into retroviral vectors and transduced into primary CD4(+) and CD8(+) T cells and displayed anti-M. tuberculosis activity. As expected, minimal murinized TCRs displayed higher cell surface expression levels and stronger anti-M. tuberculosis activity than wild-type TCRs. To the best of our knowledge, this is the first report describing TCRs targeting M. tuberculosis antigens and this investigation provides the basis for future TCR gene-based immunotherapies that can be designed for the treatment of immunocompromised M. tuberculosis-infected patients.

[Differentiation of 5-azacytidine-induced bone marrow stromal stem cells transduced with hepatocyte growth factor gene].

OBJECTIVE: To examine the differentiation of 5-azacytidine-induced bone marrow stromal stem cells (BMSCs) into cardiomyocyte-like cells and hepatocyte growth factor (HGF) gene expression after HGF gene transfection. METHODS: 5-azacytidine was used to induce beagle dog BMSCs to differentiate into cardiomyocyte-like cells. Morphological observation and immunohistochemistry were performed to detect the expression of the markers of cardiomyocyte-like cells including beta-myosin heavy chain (beta-MHC) and alpha-sarcomeric actin. The cells were then transfected with Ad-HGF, and the mRNA and protein expressions of HGF gene were detected by RT-PCR and ELISA, respectively. RESULTS: After 4 weeks of induction with 5-azacytidine, the BMSCs differentiated into cardiomyocyte-like cells. The expressions of HGF at the mRNA and protein levels were confirmed in the cells after transfection with Ad-HGF. The peak HGF protein secretion was 10(3) ng/ml at 48 h after transfection. CONCLUSION: Ad-HGF can efficiently transfect BMSCs induced with 5-azacytidine, and this result provides basic experimental evidence for biotherapy of ischemic heart disease using BMSCs.

[Effect of vascular endothelial growth factor and tumor necrosis factor receptor for treatment of avascular necrosis of the femoral head in rabbits].

OBJECTIVE: To evaluate the therapeutic effect of vascular endothelial growth factor (VEGF) and tumor necrosis factor receptor (TNFR) on avascular necrosis of the femoral head in rabbits. METHODS: Avascular necrosis of the femoral head was induced in 26 New Zealand white rabbits by injections of horse serum and prednisolone. The rabbits were then divided into VEGF/TNFR treatment group, VEGF treatment group, and untreated model group, with another 4 normal rabbits as the normal control group. In the two treatment groups, the therapeutic agents were injected percutaneously into the femoral head. Enzyme-linked immunosorbent assay was performed to determine the concentration of TNF-alpha in rabbit serum followed by pathological examination of the changes in the bone tissues, bone marrow hematopoietic tissue and the blood vessels in the femoral head. RESULTS: Compared with the model group, the rabbits with both VEGF and TNFR treatment showed decreased serum concentration of TNF-alpha with obvious new vessel formation, decreased empty bone lacunae in the femoral head and hematopoietic tissue proliferation in the bone marrow cavity. CONCLUSION: Percutaneous injection of VEGF and TNFR into the femoral head can significantly enhance bone tissue angiogenesis and ameliorate osteonecrosis in rabbits with experimental femoral head necrosis.