The T-helper cells 17 instead of Tregs play the key role in acute rejection after pediatric liver transplantation.

Th17 and imbalance of Treg/Th17 might be one of the mechanisms of acute rejection. We aim to explore the role of Th17s in the balance of Treg/Th17 in acute rejection after LT in children diagnosed with BA. The ratios of Treg and Th17 in peripheral blood were detected by flow cytometry pre-LT, post-LT, and when rejection occurred. Treg proportion was higher before transplantation than at 2 weeks and 1 month after transplantation, with no statistical difference between 2 weeks and 1 month. However, Treg proportions were lower in pediatric recipients than healthy controls. The proportion of Tregs before anti-rejection treatment was lower than control group, with no statistical difference compared to the stable group and it showed no difference compared with that at 2 weeks and 1 month post-LT. The Th17 proportions were higher at 2 weeks and 1 month after transplantation than healthy controls. The Th17 proportion under the circumstances of rejection was higher than that in the stable group and control group; the proportion in stable group was higher than that in control group. After anti-rejection therapy, the proportions of Th17 were lower than those before therapy. In conclusion, the imbalance of Treg/Th17, especially Th17s instead of Tregs, may be one of the important mechanisms in acute rejection.

MHC II-, but not MHC II+, hepatic Stellate cells contribute to liver fibrosis of mice in infection with Schistosoma japonicum.

Hepatic stellate cells (HSCs) are considered as the main effector cells in vitamin A metabolism and liver fibrosis, as well as in hepatic immune regulation. Recently, researches have revealed that HSCs have plasticity and heterogeneity, which depend on their lobular location and whether liver is normal or injured. This research aimed to explore the biological characteristics and heterogeneity of HSCs in mice with Schistosoma japonicum (S. japonicum) infection, and determine the subpopulation of HSCs in pathogenesis of hepatic fibrosis caused by S. japonicum infection. Results revealed that HSCs significantly increased the expressions of MHC II and fibrogenic genes after S. japonicum infection, and could be classified into MHC II+ HSCs and MHC II- HSCs subsets. Both two HSCs populations suppressed the proliferation of activated CD4+T cells, whereas only MHC II- HSCs displayed a myofibroblast-like phenotype. In response to IFN-γ, HSCs up-regulated the expressions of MHC II and CIITA, while down-regulated the expression of fibrogenic gene Col1. In addition, praziquantel treatment decreased the expressions of fibrogenic genes in MHC II- HSCs. These results confirmed that HSCs from S. japonicum-infected mice have heterogeneity. The MHC II- α-SMA+ HSCs were major subsets of HSCs contributing to liver fibrosis and could be considered as a potential target of praziquantel anti-fibrosis treatment.

The quantitative and functional changes of NK cells in mice infected with Angiostrongylus cantonensis.

Angiostrongylus cantonensis is a neurotropic parasite which can cause injury to central nervous system and eosinophilic meningitis to human. Natural killer (NK) cells are specialized innate lymphocytes important in early defense against pathogens as in a variety of intracellular bacterial, viral, and protozoan infections. However, the number and function of NK cells in extracellular parasitic infection of A. cantonensis are unclear. In this study, on A. cantonensis infected mice which may mimic the human's infection, we found that the percentage of splenic NK cells and the absolute number of peripheral blood NK cells were decreased at 21-day post infection compared with that of controls. When administrating with albendazole treatment at early stage of the infection, the changes of NK cells could be avoided. Further analysis confirmed that the reduction of NK cells was due to their apoptosis manifested as increased expressions of annexin V and activated caspase-3 after 16-day post infection. Moreover, both activated and inhibitory receptors such as CD16, CD69, NKG2D, and Ly49a on NK cells were down-regulated after 16-day post infection. Interestingly, NK cells isolated from mice of 21-day post infection showed enhanced IFN-γ production when stimulated with IL-12 for 24 h and cytotoxicity to YAC-1 cells, as well as elevated CD107a expression. It is evident that NK cell population and its function were changed in A. cantonensis infected mice, suggesting their involvement in pathogenesis of the infection.

The clinical characteristics analysis of serum markers for the cardiovascular system in early-stage COVID-19 patients.

Background: This study aimed to investigate alterations in serum markers [creatine kinase-MB (CKMB), cardiac troponin T (cTnT), myoglobin (Myo), B-type natriuretic peptide (BNP), D-dimer (DD), procalcitonin (PCT) and interleukin-6 (IL6)] in early Omicron variant infection and analyzed their correlation with clinical parameters. Methods: Retrospective analysis of 1,138 mild/asymptomatic cases at Tianjin First Central Hospital, including age, gender, serum markers and nucleic acid test results. Statistical analysis used SPSS software, version 24.0. Results: Elevated cTnT, BNP (125-400), and DD (0.55-1.10) levels were prevalent at 12.92%, 15.64%, and 14.50%, respectively. Females had significantly higher proportions with slightly elevated BNP (19.34%) and DD (19.69%) levels. Patients over 35 had a higher proportion of slight elevation in BNP (20.00%). Abnormal levels of serum markers were significantly associated with older age, increased PCT and IL6 levels, as well as delayed nucleic acid clearance. Additionally, levels of immunoglobulin G (IgG) were notably reduced in these cases. Patients with prolonged nucleic acid clearance (>14 days) had higher BNP and DD levels upon admission. Logistic regression identified PCT (OR = 237.95) as the most significant risk factor for abnormal serum markers for cardiovascular system injury. Conclusion: Early Omicron infection might do subclinical damage to the cardiovascular system. Elevated cTnT, BNP and DD levels were correlated with age, gender, inflammatory factors, and IgG. Notably, high PCT level emerged as the most robust predictor of abnormal serum biomarkers.

Altered Liver Enzyme Markers in Patients with Asymptomatic, and Mild Omicron Infection: A Retrospective Study.

Purpose: The emergence of the SARS-CoV-2 Omicron variant has posed a significant global public health challenge. Elucidating the laboratory profiles of individuals infected with this variant is crucial for assessing organ damage. This study aimed to investigate the variations in liver function tests and their correlation with demographic characteristics and inflammatory markers in patients with early Omicron variant infections. Patients and Methods: A retrospective cohort study was conducted on 1133 mild or asymptomatic COVID-19 cases at Tianjin First Central Hospital. Data on age, gender, body mass index (BMI), and serum markers were collected and analyzed. Statistical analyses were performed using SPSS software, version 24.0. Results: Abnormal liver function parameters, including aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT), and total bilirubin (TBIL), were observed in 314 (27.71%) patients. "Hepatocellular type" was identified in 56 (4.94%) patients, "cholestatic type" in 185 (16.33%) patients, and "mixed type" in 73 (6.44%) patients. In the mixed group, we observed a pronounced elevation in the levels of ALT, AST, and GGT. Moreover, the hepatocellular group exhibited a statistically significant increase in AST and ALT concentrations relative to both the normal and cholestatic groups. Notably, the cholestatic group demonstrated a substantial increment in ALP levels. Males had a significantly higher prevalence of "abnormal liver enzyme markers" compared to females. Patients with "abnormal liver enzyme markers" exhibited significantly decreased immunoglobulin G (IgG) levels and elevated levels of inflammatory markers, including procalcitonin (PCT), interleukin-6 (IL6), as well as C-reactive protein (CRP) compared to normal group. Logistic regression analysis revealed that male gender and PCT levels were significantly associated with the risk of abnormal liver enzyme markers. Patients in hepatocellular group were likely accompanied with high CRP levels, whereas those in the cholestatic type were associated with high IL6 levels. Conclusion: Early Omicron infection might cause liver stress response. Elevated liver enzyme marker levels were correlated with age, gender, inflammatory factors, and IgG.

The value of age IgG and IL6 in estimating time of viral clearance in asymptomatic or mild patients with COVID-19.

Background: The aim of this study was to investigate the relationship between Age, immunoglobin G (IgG), immunoglobin M (IgM), procalcitonin (PCT), and interleukin-6 (IL6), and the time to clear viral nucleic acids in asymptomatic and mild coronavirus disease 2019 (COVID-19) patients, as well as evaluated the predictive value of these biochemical indicators. Methods: We performed a retrospective analysis on 1,570 individuals who were admitted to Tianjin First Central Hospital and diagnosed with asymptomatic or mild cases. Laboratory data were collected, including age, gender, levels of IgG, IgM, PCT and IL6, as well as results of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) nucleic acid test. These data were statistically analyzed using SPSS software, version 24.0. Results: The results indicated that among mild patients, Age, IgG, and the time to clear viral nucleic acids were higher than asymptomatic patients (p < 0.05). And the time to clear viral nucleic acids was significantly correlated with Age, IgG, IgM, PCT, and IL6 (p < 0.05), IgG (r = -0.445, p < 0.001) showed moderate correlations. Using logistic regression analysis, we identified older age, high IL6 levels, and low IgG levels were risk factors for nucleic acid clearance exceeding 14 days (p < 0.05). When combining these three indicators to predict the probability of nucleic acid clearance exceeding 14 days in the 1,570 patients, the AUROC was found to be 0.727. Conclusion: Age, IgG, and IL6 could potentially serve as useful predictors for nucleic acid clearance exceeding 14 days in asymptomatic and mild COVID-19 patients.

Clinical and immunological features of convalescent pediatric patients infected with the SARS-CoV-2 Omicron variant in Tianjin, China.

COVID-19 has spread surprisingly fast worldwide, and new variants continue to emerge. Recently, the World Health Organization acknowledged a new mutant strain "Omicron", with children were accounting for a growing share of COVID-19 cases compared with other mutant strains. However, the clinical and immunological characteristics of convalescent pediatric patients after Omicron infection were lacking. In this study, we comparatively analyzed the clinical data from pediatric patients with adult patients or healthy children and the effects of SARS-CoV-2 vaccine on the clinical and immune characteristics in convalescent pediatric patients. Our results indicated that convalescent pediatric patients had unique clinical and immune characteristics different from those of adult patients or healthy children, and SARS-CoV-2 vaccination significantly affected on the clinical and immune characteristics and the prevention of nucleic acid re-detectable positive (RP) in convalescent patients. Our study further deepens the understanding of the impact of Omicron on the long-term health of pediatric patients and provides a valuable reference for the prevention and treatment of children infected with Omicron.

The pentapeptide PLNPK inhibits systemic lupus erythematosus-associated renal damage.

OBJECTIVE: This study aimed to observe the therapeutic effect of pentapeptide PLNPK on systemic lupus erythematosus (SLE) in mice, and to study the inhibitory effect of PLNPK on activation of T cells in vivo. METHODS: Murine SLE-like chronic graft-versus-host disease (cGVHD) was induced. After treatment with PLNPK (100, 200, 400 µg/kg per day) for 70 days, serum blood urea nitrogen, creatine, total cholesterol, triglyceride and albumin were tested, and serum levels of anti-dsDNA and anti-histone antibodies were detected by ELISA. The pathological damage and IgG deposition in the kidney were identified. Concanavalin A (ConA)-induced T lymphocyte proliferation in SLE mice was also tested. RESULTS: PLNPK can reduce serum blood urea nitrogen, creatine, total cholesterol, triglyceride, and elevate serum albumin, and reduce levels of anti-dsDNA and anti-histone antibodies in the murine SLE model. Pathological damage and IgG deposition in the kidney were reduced in the PLNPK-treated group. PLNPK inhibited T lymphocyte infiltration in kidney tissues and ConA-induced T lymphocyte proliferation in SLE mice. CONCLUSION: Our results demonstrate that PLNPK can suppress T cell function and reduce the production of autoantibodies, and may be a feasible and effective therapy in the SLE model.

Regulatory effect of rat bone marrow mesenchymal stem cells on Treg/Th17 immune balance in vitro.

Bone marrow mesenchymal stem cells (BM­MSCs) regulate the balance between regulatory T cells (Tregs) and T helper 17 (Th17) cells. However, the role of different factors on BM­MSCs­mediated regulation of the Treg/Th17 balance is unknown. BM­MSCs and CD4+ T lymphocytes were co­cultured with various treatments. The ratio of Treg/Th17 cells was calculated and the expression of different cytokines was measured. BM­MSCs were found to have a proliferative effect on Th17 cells at a basal concentration and at a 2­fold increase in the number of BM­MSCs. However, when the number of BM­MSCs used was increased 4­fold, they had an inhibitory effect on the Th17 cells. The effect of BM­MSCs on Tregs was inhibited by the addition of tacrolimus but not rapamycin. The effect of BM­MSCs on Th17 cells was inhibited by rapamycin. Additionally, the effect of BM­MSCs on Tregs were inhibited by the addition of a transforming growth factor­ß (TGF­ß) blocker, whereas these TGF­ß­blockers had no effect on Th17 cells. Addition of an interleukin (IL)­2 blocker reduced the proportion of Th17 cells when co­cultured with a high number of MSCs compared with the low concentration group and the proportion of Treg cells was significantly decreased when cells were treated with an IL­2 blocker compared with the control group. Together, these results showed the varying effects of MSCs on the ratio of Treg/Th17, its dependence on the number of MSCs and the effects of cytokines in inducing these changes in the balance.

Calcitonin gene-related peptide increases proliferation of human HaCaT keratinocytes by activation of MAP kinases.

Psoriasis is a chronic disease characterized by keratinocyte hyperproliferation and inflammation. It has been demonstrated that the expression of calcitonin gene-related peptide (CGRP) is elevated in psoriasis lesions and CGRP-containing neuropeptide nerve fibers are denser in the psoriatic epidermis. CGRP has been previously described to influence proliferation of several cell types, such as Schwann cell, tracheal epithelial cells, and human gingival fibroblasts. In the present study, we determined the effect of CGRP on HaCaT keratinocyte proliferation and the role of mitogen-activated protein kinases (MAPKs) in CGRP induced keratinocyte proliferation. Our data indicate CGRP increased [(3)H]-thymidine incorporation and MTT activity of HaCaT in a concentration-dependent manner. CGRP also enhanced serum-induced HaCaT cell proliferation. HaCaT cells cultured with CGRP had a significant increase in phosphorylated ERK1/2, p38 and JNK, and CGRP induced DNA synthesis was inhibited by PD 98059 or SB 203580, selective inhibitors of MAP kinase kinase (MEK, which is upstream from ERK) and p38, respectively. These findings suggest that HaCaT cell proliferate in response to CGRP, which is mediated by phosphorylation of ERK1/2 and p38 MAPK.

Different phenotypes of CD4+CD25+Foxp3+ regulatory T cells in recipients post liver transplantation.

CD4+ regulatory T cells (Tregs) play an important role in inducing immune tolerance in organ transplantation, which can be divided into CD45RA+Tregs (resting Tregs, rTregs) and CD45RO+Tregs (activated Tregs, aTregs). Currently, the expressions and phenotypic changes of Tregs in recipients after liver transplantation (LT) is unknown. We therefore investigated the expression and transformation of rTregs and aTregs in 83 cases of recipients with normal status post-LT. The percentages of CD45RA, CD45RO, CD31 in CD4+Tregs were detected by flow cytometry and the effective factors were analyzed. In LT recipients, the percentage of CD45RO+Tregs in CD4+Tregs was higher than that of CD45RA+Tregs. There was significant difference in the ratio of positive Foxp3 between CD45RA+Tregs and CD45RO+Tregs. Percentage of CD45RA+Tregs was higher in pediatric group than that in adult group, whereas percentage of CD45RO+Tregs was lower in the pediatric group. However, it was different only in CD45RO+Tregs in various survival periods post-LT. In conclusion, Tregs pool in human was heterogeneous post-LT and contained different subsets in phenotypes. Upon stimulation by donor graft, percentages of CD4+Tregs and CD45RO+Tregs were increased post-LT and most of rTregs was transformed into aTregs in peripheral blood, and rTregs and aTregs were both related to recipients' ages.

Kaempferol: a new immunosuppressant of calcineurin.

Calcineurin (CN), the Ca(2+)/calmodulin (CaM)-dependant protein phosphatase, is the target for immunosuppressive drugs cyclosporine A (CsA) and FK506. These immunosuppressants can inhibit CN activity after binding with respective immunophilins. Based on the model of screening by using p-nitrophenyl phosphate as a substrate for preliminary screening and (32)P-labeled 19-residue phosphopeptide as a specific substrate for final determination, we found Kaempferol, a natural flavonol, could inhibit CN activity in purified enzyme and Jurkat T-cells. Unlike CsA and FK506, CN inhibition by kaempferol is independent of matchmaker protein and the inhibitory manner is noncompetitive. Through investigation of inhibitions for CNA and a series of its truncated mutants, we suggested that Kaempferol could directly act on the catalytic domain. Data also indicated that the CN inhibition by kaempferol could be enhanced when the enzyme was activated in the presence of CaM and CNB. CNB is necessary for mediating inhibition of enzyme by kaempferol. The result of RT-PCR also indicated that kaempferol had an inhibitory activity against IL-2 gene expression in activated Jurkat cells. All data suggested that kaempferol could be a new immunosuppressant of CN.

Tripeptide tyroserleutide plus doxorubicin: therapeutic synergy and side effect attenuation.

BACKGROUND: Tripeptide tyroserleutide (YSL) is a novel small molecule anti-tumor polypeptide that has been shown to inhibit the growth of human liver cancer cells. In this study, we investigated the effects of YSL plus doxorubicin on the growth of human hepatocellular carcinoma BEL-7402 cells that had been transplanted into nude mice. METHODS: Nude mice bearing human hepatocellular carcinoma BEL-7402 tumors were treated with successive intraperitoneal injections of saline; low-, mid-, or high-dose doxorubicin; or low-, mid-, or high-dose doxorubicin plus YSL. Effects on the weight and volume of the tumors were evaluated. RESULTS: Co-administration of YSL and high-dose doxorubicin (6 mg/kg every other day) prolonged the survival time of tumor-bearing mice as compared to high-dose doxorubicin alone. As well, the anti-tumor effects of mid- and low-dose doxorubicin (2 and 0.7 mg/kg every other day, respectively) were enhanced when supplemented with YSL; the tumor growth inhibition rates for YSL plus doxorubicin were greater than the inhibition rates for the same dosages of doxorubicin alone. The combination of YSL and doxorubicin decreased chemotherapy-associated weight loss, leukocyte depression, and heart, liver, and kidney damage as compared to doxorubicin alone. CONCLUSION: The combination of YSL plus doxorubicin enhances the anti-tumor effect and reduces the side effects associated with doxorubicin chemotherapy.

A new pentapeptide compound, PLNPK, ameliorates anti-glomerular basement membrane nephritis in Wistar rats.

PLNPK is a pentapeptide compound extracted from pig spleen with a Pro-Leu-Asn-Pro-Lys molecular structure. The spleen is the biggest immune organ in the body, in which there are lots of immunocytes and immune molecules. Our pilot study showed that PLNPK could suppress the transformation and proliferation of T lymphocytes and the production of antibodies in mice. It is widely accepted that most types of glomerulonephritis are immunological diseases caused by the reaction of antigen and antibody. Both humoral immunity and cell-mediated immunity contribute to the progress of these diseases, and suppression of immunoreactions and inflammation is important to ameliorate nephritis. After the immunosuppressive effects of this compound were discovered, this study also examined whether PLNPK had beneficial effects on a rat model of glomerulonephritis. The results suggested PLNPK (200microg/kg/d and 400microg/kg/d) reduced urinary protein excretion, lessened the deposit of autoantibodies along the glomerular basement membrane (GBM), reduced formation of crescent and protein casts, and ameliorated glomerular fibrosis and GBM injury. After treatment with PLNPK (200microg/kg/d and 400microg/kg/d) for 7 days, macrophage infiltration in the glomeruli was markedly reduced. Our results suggest that PLNPK has a beneficial effect on rat anti-GBM nephritis.

[Evaluation of the inhibitory effect of tripeptide tyroservatide on growth of human hepatocellular carcinoma using a hollow fiber assay].

OBJECTIVE: To investigate the inhibitory effect of tyroservatide (YSV) on growth of hepatocellular carcinoma cells. METHODS: In vitro effects of YSV on five human hepatocellular carcinoma cell lines were assayed by MTS. In vivo effects of YSV on 5 human hepatocellular carcinoma cell lines were assayed by hollow fiber tumor model. RESULTS: After treatment with YSV at a dose of 0.1 approximately 1.6 mg/ml, the growth of the five cell lines was significantly inhibited in vitro compared with that of the control group (P < 0.05). Especially, YSL remarkably inhibited the growth of human hepatocellular carcinoma BEL-7402 cells, i.e. the cell growth was inhibited by 63.3% after treatment with YSL at 1.6 mg/ml. The hollow fiber tumor model demonstrated that YSL (320 microg x kg(-1) x d(-1) and 640 microg x kg(-1) x d(-1)) treatment significantly inhibited the in vivo growth of the five cancer cell lines compared with that in the saline control (P < 0.05). YSL showed the highest level of inhibition of human BEL-7402 hepatocellular carcinoma cells, with an inhibitory index of 53.1% at 320 microg x kg(-1) x d(-1). CONCLUSION: As a new method, hollow fiber assay may be used to evaluate the inhibitory effect of drugs on different tumor cells in vivo, rapidly, accurately and economically. Our results provide an instruction and evidence for clinical use of YSV.

Combined acupuncture and HuangDiSan treatment affects behavior and synaptophysin levels in the hippocampus of senescence-accelerated mouse prone 8 after neural stem cell transplantation.

Sanjiao acupuncture and HuangDiSan can promote the proliferation, migration and differentiation of exogenous neural stem cells in senescence-accelerated mouse prone 8 (SAMP8) mice and can improve learning and memory impairment and behavioral function in dementia-model mice. Thus, we sought to determine whether Sanjiao acupuncture and HuangDiSan can elevate the effect of neural stem cell transplantation in Alzheimer's disease model mice. Sanjiao acupuncture was used to stimulate Danzhong (CV17), Zhongwan (CV12), Qihai (CV6), bilateral Xuehai (SP10) and bilateral Zusanli (ST36) 15 days before and after implantation of neural stem cells (5 × 105) into the hippocampal dentate gyrus of SAMP8 mice. Simultaneously, 0.2 mL HuangDiSan, containing Rehmannia Root and Chinese Angelica, was intragastrically administered. Our results demonstrated that compared with mice undergoing neural stem cell transplantation alone, learning ability was significantly improved and synaptophysin mRNA and protein levels were greatly increased in the hippocampus of mice undergoing both Sanjiao acupuncture and intragastric administration of HuangDiSan. We conclude that the combination of Sanjiao acupuncture and HuangDiSan can effectively improve dementia symptoms in mice, and the mechanism of this action might be related to the regulation of synaptophysin expression.

Inhibiting interleukin-18 production through the mitogen-activated protein kinase pathway, a potential role of corticotropin-releasing hormone in chronic plaque psoriasis.

Corticotropin-releasing hormone (CRH) and CRH receptors (CRH-Rs) are expressed in the skin; CRH-R1 is the predominant receptor. Whether the CRH/CRH-R1 system plays a role in psoriasis has not yet been assessed. Immunohistochemistry, real-time RT-PCR, ELISA assay, and Western blot analysis were used to investigate the expression of CRH/CRH-R1 in patients with chronic plaque psoriasis and that of IL-18 in CRH-treated HaCaT cells. CRH and CRH-R1 were downregulated in patients with chronic plaque psoriasis. In vitro, CRH attenuated the expression of IL-18 by a mitogen-activated protein kinase signaling pathway through CRH-R1 in HaCaT cells. Thus, an aberrant cutaneous CRH/CRH-R1 system exists in lesions from chronic plaque psoriasis which might play a role in psoriasis and offers further evidence for the study of CRH in the skin.

A Novel Oxidized Low Density Lipoprotein-binding Protein in Macrophage.

Scavenger receptor A(SR-A)on the mouse peritoneal macrophages(MPM) mediates the endocytic uptake of oxidized low density lipoproteins(ox-LDL). However, using ligand blotting and immunoblotting, a novel macrophage membrane protein binding to ox-LDL with estimated molecular mass of 92 kD was found. This membrane protein could not bind to ac-LDL. Its binding to ligands was not affected by reducing reagents either. Preincubation with medium containing neuraminidase dramatically decreased binding of the 92 kD membrane protein to ox-LDL. Excess amounts of ox-LDL could completely block the binding of (125)I ox-LDL to 92 kD membrane protein, but polyI, dextran sulfate and fucoidin showed partial competitive inhibition effects to the binding. These results suggest that the novel 92 kD membrane protein plays important role in the MPM uptake of ox-LDL.

Effect of Protein Kinase C Inhibitor on Scavenger Receptor in Human U937 Macrophage-like Cells.

In order to investigate effects of cell protein phosphorylation on scavenger receptor, human U937 macrophage-like cells were treated with protein kinase C inhibitor staurosporine, then the cells were incubated with (125)I ox-LDL or ox-LDL, and the cellular degradation of (125)I ox-LDL, its binding to receptor and the internalization of cell surface ox-LDL receptor complex as well as the accumulation of lipids within cells were measured separately. Moreover, the effects of the drug on expression of cell surface receptor were observed by means of autoradiography. The results indicated that staurosporine could enhance U937 cells to bind lipids and stimulate scavenger receptor expression, and could reduce degradation of lipids by U937 cells and the accumulation of cholesterol within the cells. It suggests that the function of scavenger receptors may be correlated with cell protein phorsphorylation.

The latest developments in synthetic peptides with immunoregulatory activities.

In the past few years, many researches have provided us with much data demonstrating the abilities of synthetic peptides to impact immune response in vitro and in vivo. These peptides were designed according to the structure of some important protein molecules which play a key role in immune response, so they act with specific targets. The class I and II MHC-derived peptides inhibit the TCR recognition of antigen peptide-MHC complex. Rationally designed CD80 and CD154-binding peptides block the interaction between cell surface costimulatory molecules on antigen-presenting cells (APCs) and T cells. Some peptides were designed to inhibit the activities of cell signal proteins, including JNK, NF-κB and NFAT. Some peptide antagonists competitively bind to important cytokines and inhibit their activities, such as TNF-α, TGF-ß and IL-1ß inhibitory peptides. Adhesion molecule ICAM-1 derived peptides block the T cell adhesion and activation. These immunoregulatory peptides showed therapeutic effect in several animal models, including collagen-induced arthritis (CIA), autoimmune cystitis model, murine skin transplant model and cardiac allograft model. These results give us important implications for the development of a novel therapy for immune mediated diseases.