Xinke Zhang

Hematopoietic effects and mechanisms of Fufang e׳jiao jiang on radiotherapy and chemotherapy-induced myelosuppressed mice.

ETHNOPHARMACOLOGICAL RELEVANCE Fufang e׳jiao jiang (FEJ), which has been widely used in clinic to replenish qi (vital energy) and nourish blood, is a famous traditional Chinese medicine formula made up of Colla corii asini (donkey-hide gelatin prepared by stewing and concentrating from the hide of Equus asinus Linnaeus.), Radix codonopsis pilosulae (the root of Codonopsis pilosula (Franch.) Nannf.), Radix ginseng rubra (the steamed and dried root of Panax ginseng C.A. Mey.), Fructus crataegi (the fruit of Crataegus pinnatifida Bunge) and Radix rehmanniae preparata (the steamed and sun dried tuber of Rehmannia glutinosa (Gaertn.) Libosch. ex Fisch. & C.A. Mey.). The present study aimed to investigate the hematopoietic effects of FEJ on myelosuppressed mice induced by radiotherapy and chemotherapy systematically and to explore the underlying hematopoietic regulation mechanisms. METHODS The myelosuppressed mouse model was induced by (60)Co radiation, cyclophosphamide and chloramphenicol. FEJ was then administered by i.g. at the dosages of 5, 10, or 20 mL/kg·d for 10d. The numbers of blood cells from peripheral blood and bone marrow nucleated cells (BMNC) were counted. Body weight and the thymus and spleen indices were also measured. The numbers of hemopoietic progenitor cells and colony-forming unit-fibroblast (CFU-F) were measured in vitro. The ratio of hematopoietic stem cells (HSC) in BMNC, cell cycle and apoptosis of BMNC were determined by flow cytometry. The histology of femoral bone was examined by H&E staining. The levels of transforming growth factor-β (TGF-β), tumor necrosis factor-α (TNF-α), erythropoietin (EPO), granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3) and interleukin-6 (IL-6) in serum were measured by ELISA. IL-1β, IL-3, IL-6 mRNA levels in spleen were detected by real-time quantitative PCR (RT-qPCR). In addition, bone marrow stromal cells (BMSC) were cultured in vitro followed by treatment with different doses of FEJ (2.5, 5, 10 μL/mL) for 48 h. Then the levels of cytokines (IL-6, SCF, GM-CSF) in the conditioned media and their mRNA levels in BMSC were determined by ELISA and RT-qPCR, respectively. RESULTS FEJ could significantly increase the numbers of peripheral blood cells and BMNC, and reverse the loss of body weight and the atrophy of thymus and spleen in a dose-dependent manner. The quantities of hemopoietic progenitor cells and CFU-F in bone marrow were also significantly increased in a dose-dependent manner after FEJ administration. A high-dose FEJ of 20 mL/kg·d could significantly increase the ratio of HSC in BMNC, promote bone marrow cells entering the proliferative cycle phase (S+G2/M) and prevent cells from proceeding to the apoptotic phase. FEJ could also improve the femoral bone marrow morphology. Furthermore, FEJ could increase the levels of GM-CSF and IL-3 and reduce the level of TGF-β in serum, and enhance the expressions of IL-1β and IL-3 mRNA in spleen. Lastly, the levels of cytokines (IL-6, SCF, GM-CSF) in the conditioned media and their mRNA levels in BMSC were elevated after treatment with FEJ. CONCLUSIONS FEJ was clearly confirmed to promote the recovery of bone marrow hemopoietic function in a myelosuppressed mouse model, which may be attributed to (i) improving bone marrow hematopoietic microenvironment; (ii) facilitating the cell proliferation and preventing BMNC from apoptosis; (iii) stimulating the expressions of IL-1β, IL-3, IL-6, SCF and GM-CSF and inhibiting the expression of TGF-β.

Intracellular transduction and potential of Tat PTD and its analogs: from basic drug delivery mechanism to application.

Introduction: It has been 20 years since the discovery of the membrane-translocating property of the HIV-1 transactivator of transcription (Tat) protein. The Tat protein transduction domain (Tat PTD) is a very promising tool for non-invasive cellular import of cargos and has been successfully applied to in vitro and in vivo delivery of different therapeutic agents for the treatment of many diseases. A growing number of reports on Tat PTD-mediated delivery have extensively revealed the mechanisms involved. Yet, due to the varied conditions used, the reports on the internalization mode of Tat PTD-cargo chimera are often varied. Areas covered: This article reviews the possible intracellular trafficking mechanisms of Tat PTD including its binding, cellular entry process, and the roles of participants of the cell membrane. The therapeutic applications via local administration, such as those for the treatment of skin, ocular, cardiac and cerebral diseases, are also reviewed. In addition, some novel systems built by different groups are elucidated, which are utilized to overcome the poor targeting efficiency of Tat PTD for the treatment of CNS diseases, cancer and other diseases via systemic administration. Expert opinion: With the development of targeting factors, such as antibodies, some cell targeting peptides and novel polymers, Tat PTD is expected to play a more efficient and/or better tolerated therapeutic role in the drug delivery field.

Preparation and in vitro immunomodulatory effect of curdlan sulfate

Different curdlan sulfates were synthesized by modification of curdlan with sulfur trioxide-pyridine complex, and the one with the highest sulfur content (9.23 ± 0.16) %, CS3, was used to study the immunomodulating effect on murine RAW264.7 macrophages and bone marrow derived dendritic cells (BMDCs). The results showed that the treatment of macrophages with CS3 could not only increase the nitric oxide (NO) release and the cytokines TNF-α, IL-6 and IL-1β production significantly, but also enhance the inducible NOS (iNOS) expression, NF-κBp65 nuclear translocation, Erk1/2 and SAPK/JNK phosphorylation. The combination of CS3 with GM-CSF upregulated immature BMDCs to express major histocompatibility complex II (MHCII) and CD11c surface markers, CD40, CD80 and CD86 costimulatory molecules, as well as the cytokines of IL-12p70 and IL-6. The surface plasmon resonance (SPR) analysis found that CS3 exhibited binding affinity against dectin-1. These results suggested that curdlan sulfate can possibly be developed as a new immunotherapy agent and anti-viral vaccine adjuvant.

Enhancing the intestinal absorption of low molecular weight chondroitin sulfate by conjugation with α-linolenic acid and the transport mechanism of the conjugates.

The purpose of this report was to demonstrate the effect of amphiphilic polysaccharides-based self-assembling micelles on enhancing the oral absorption of low molecular weight chondroitin sulfate (LMCS) in vitro and in vivo, and identify the transepithelial transport mechanism of LMCS micelles across the intestinal barrier. α-Linolenic acid-low molecular weight chondroitin sulfate polymers(α-LNA-LMCS) were successfully synthesized, and characterized by FTIR, (1)HNMR, TGA/DSC, TEM, laser light scattering and zeta potential. The significant oral absorption enhancement and elimination half-life (t₁/₂) extension of LNA-LMCS2 in rats were evidenced by intragastric administration in comparison with CS and LMCS. Caco-2 transport studies demonstrated that the apparent permeability coefficient (Papp) of LNA-LMCS2 was significantly higher than that of CS and LMCS (p<0.001), and no significant effects on the overall integrity of the monolayer were observed during the transport process. In addition, α-LNA-LMCS micelles accumulated around the cell membrane and intercellular space observed by confocal laser scanning microscope (CLSM). Furthermore, evident alterations in the F-actin cytoskeleton were detected by CLSM observation following the treatment of the cell monolayers with α-LNA-LMCS micelles, which further certified the capacity of α-LNA-LMCS micelles to open the intercellular tight junctions rather than disrupt the overall integrity of the monolayer. Therefore, LNA-LMCS2 with low cytotoxicity and high bioavailability might be a promising substitute for CS in clinical use, such as treating osteoarthritis, atherosclerosis, etc.

Tat PTD-endostatin: A novel anti-angiogenesis protein with ocular barrier permeability via eye-drops.

BACKGROUND Endostatin, a specific inhibitor of endothelial cell proliferation and angiogenesis, has been proved to have effects on ocular neovascular diseases by intraocular injection. In order to increase its permeability to ocular barriers and make it effective on fundus oculi angiogenesis diseases via non-invasive administration (eye drops), endostatin was fused to Tat PTD via a genetic engineering method. METHODS Most of the Tat PTD- endostatin was expressed as inclusion bodies in Escherichia coli, so pure and active Tat PTD-endostatin was prepared by a series of operations, including inclusion body denaturation, refolding and chromatography. The anti-angiogenesis activity of Tat PTD-endostatin was investigated by cell proliferation experiments and chick embryo chorioallantoic membrane assay. In addition, its translocating ability and concrete entry mechanism into cells were also investigated by fluorescence microscope and flow cytometry. The penetrating ability to ocular barriers was also studied by immunohistochemistry. A mouse choroidal neovascularization model was established to investigate the pharmacodynamics of Tat PTD-endostatin. RESULTS The obtained Tat PTD-endostatin had excellent anti-angiogenesis activity and was superior to Es in cellular translocating. Macropinocytosis may be the dominant route of entry of Tat PTD-endostatin into cells. Tat PTD-endostatin could cross ocular barriers and arrive at the retina after eye-drop administration. In addition, it displayed inhibitory effects on choroidal neovascularization via eye drops. CONCLUSIONS Tat PTD-endostatin possessed excellent ocular penetrating ability and anti-angiogenesis effects. GENERAL SIGNIFICANCE Tat PTD is a promising ocular delivery tool, and Tat PTD-endostatin is a potential drug for curing fundus oculi angiogenesis diseases.

Effect and mechanisms of curdlan sulfate on inhibiting HBV infection and acting as an HB vaccine adjuvant

In this study, the effect and mechanisms of curdlan sulfate (CS3) on hepatitis B virus (HBV) infection and promoting immune response of the mice immunized with recombinant hepatitis B surface protein (HBsAg) were investigated. The results showed that CS3 could inhibit HBV infection of HepG2 and HepaRG cells, especially the process of HBV particle binding to the cell surfaces. The surface plasmon response (SPR) technology indicated that CS3 could bind with recombinant HBsAg and the binding ability depended on the content of sulfate groups on the polysaccharide chains. Co-administration of CS3 to BALB/c mice immunized with HBsAg significantly enhanced the influx of macrophages and dendritic cells in spleen, increased antigen-specific CD4+ and CD8+ cell numbers, and promoted splenocyte proliferation. The titer of HBsAg-specific antibodies was also augmented by use of CS3 as a vaccine adjuvant. The higher expression of interferon (IFN)-γ, lower expression of interleukin (IL)-4, and higher IgG2a/IgG1 ratio within the anti-HBsAg antibodies in mice immunized with HBsAg plus CS3 than those in mice receiving HBsAg alone indicated that CS3 induced a shift toward a Th1-biased immune response. These results presented that CS3 could be developed as an immunotherapy agent or vaccine adjuvant for HBV infection treatment or prevention.

The in vivo immunomodulatory and synergistic anti-tumor activity of thymosin α1–thymopentin fusion peptide and its binding to TLR2

In the present study, the immunomodulatory and synergistic anti-tumor activity of thymosin α1-thymopentin fusion peptide (Tα1-TP5) was investigated in vivo. In addition, the potential receptor of Tα1-TP5 was investigated by surface plasmon resonance (SPR) binding studies. It was found that Tα1-TP5 (305 μg/kg) alleviated immunosuppression induced by hydrocortisone (HC). Tα1-TP5 (305 μg/kg) combined with cyclophosphamide (CY) had a better tumor growth inhibitory effect than CY alone. Furthermore, Tα1-TP5 had a higher affinity (KD=6.84 μmol/L) to toll-like receptor 2 (TLR2) than Tα1 (K(D)=35.4 μmol/L), but its affinity was not significantly different from that of TP5. The results of our present work indicate that Tα1-TP5 can possibly be developed as a new immunomodulatory agent.

Impact of donor binding on polymerization catalyzed by KfoC by regulating the affinity of enzyme for acceptor

BACKGROUND Currently marketed chondroitin sulfate isolated from animal sources and structurally quite heterogeneous. Synthesis of structurally defined chondroitin sulfate is highly desired. The capsular polysaccharide from Escherichia coli strain K4 is similar to chondroitin, and its biosynthesis requires a chondroitin polymerase (KfoC). The essential step toward de novo enzymatic synthesis of chondroitin sulfate, synthesis of chondroitin, could be achieved by employing this enzyme. METHODS Structurally defined acceptors and donor-sugars were prepared by chemoenzymatic approaches. In addition, surface plasmon resonance was employed to determine the binding affinities of individual substrates and donor-acceptor pairs for KfoC. RESULTS KfoC has broad donor substrate specificity and acceptor promiscuity, making it an attractive tool enzyme for use in structurally-defined chimeric glycosaminoglycan oligosaccharide synthesis in vitro. In addition, the binding of donor substrate molecules regulated the affinity of KfoC for acceptors, then influenced the glycosyl transferase reaction catalyzed by this chondroitin polymerase. CONCLUSION AND GENERAL SIGNIFICANCE These results assist in the development of enzymatic synthesis approaches toward chimeric glycosaminoglycan oligosaccharides and designing future strategies for directed evolution of KfoC in order to create mutants toward user-defined goals.

Tat PTD-Endostatin-RGD: A novel protein with anti-angiogenesis effect in retina via eye drops

BACKGROUND Diabetic retinopathy is a leading cause of blindness. The objective was to design a novel fusion protein, Tat PTD-Endostatin-RGD, to treat retinal neovascularization via eye drops instead of traditional intravitreal injection trepapeutical methods. METHOD The anti-angiogenesis ability was evaluated in vitro by chick embryo chorioallantoic membrane assay, wound healing assay and tube formation assay. Corneal barrier and blood-retina barrier were constructed in vitro to investigate the penetration ability of Tat PTD-Endostatin-RGD. Western blot was used to detect the integrin αvβ3 expression level in rat retina microvascular endothelial cells which was stimulated by S-nitroso-N-acetylpenicillamine. The binding affinity of Tat PTD-Endostatin-RGD to integrin αvβ3 was investigated by evaluating the penetration ability on blood-retina barriers treated with S-nitroso-N-acetylpenicillamine. The pharmacodynamics and efficacy analysis were further carried out in the oxygen-induced retinopathy model in vivo. In addition, the pharmacokinetic profile via eye drops was studied on a C57BL/6 mice model. RESULT Tat PTD-Endostatin-RGD showed high anti-angiogenesis activity and high ability to penetrate these two barriers in vitro. The Western blot results indicated S-nitroso-N-acetylpenicillamine upregulated the expression level of integrin αvβ3 in a dose-dependent manner. Tat PTD-Endostatin-RGD showed a high affinity to rat retina microvascular endothelial cells treated with S-nitroso-N-acetylpenicillamine. The results showed that Tat PTD-Endostatin-RGD could inhibit abnormal angiogenesis in retina via eye drops. CONCLUSION Tat PTD-Endostatin-RGD showed high penetration ability through ocular barriers, bound specifically to integrin αvβ3 and effectively inhibited the abnormal angiogenesis. GENERAL SIGNIFICANCE Tat PTD-Endostatin-RGD represents a potent novel drug applied via eye drops for fundus oculi neovascularization diseases.

Characterization of heparan sulfate N-deacetylase/N-sulfotransferase isoform 4 using synthetic oligosaccharide substrates

BACKGROUND The final structure of heparan sulfate chains is strictly regulated in vivo, though the biosynthesis is not guided by a template process. N-deacetylase/N-sulfotransferase (NDST) is the first modification enzyme in the HS biosynthetic pathway. The N-sulfo groups introduced by NDST are reportedly involved in determination of the susceptibility to subsequent processes catalyzed by C5-epimerse and 3-O-sulfotransferases. Understanding the substrate specificities of the four human NDST isoforms has become central to uncovering the regulatory mechanism of HS biosynthesis. METHODS Highly-purified recombinant NDST-4 (rNDST-4) and a selective library of structurally-defined oligosaccharides were employed to determine the substrate specificity of rNDST-4. RESULTS Full-length rNDST-4 lacks obvious N-deacetylase activity, and displays only N-sulfotransferase activity. Unlike NDST-1, NDST-4 did not show directional N-sulfotransferase activity while the N-deacetylase domain was inactive. CONCLUSION AND GENERAL SIGNIFICANCE Individual NDST-4 could not effectively assume the key role in the distribution of N-S domains and N-Ac domains in HS biosynthesis in vivo.