ABSTRACT
Developing new therapeutic agents for cancer immunotherapy is highly demanding due to the low response ratio of PD-1/PD-L1 blockade in cancer patients. Here, we discovered that the novel immune checkpoint VISTA is highly expressed on a variety of tumor-infiltrating immune cells, especially myeloid derived suppressor cells (MDSCs) and CD8+ T cells. Then, peptide C1 with binding affinity to VISTA was developed by phage displayed bio-panning technique, and its mutant peptide VS3 was obtained by molecular docking based mutation. Peptide VS3 could bind VISTA with high affinity and block its interaction with ligand PSGL-1 under acidic condition, and elicit anti-tumor activity in vivo. The peptide DVS3-Pal was further designed by d-amino acid substitution and fatty acid modification, which exhibited strong proteolytic stability and significant anti-tumor activity through enhancing CD8+ T cell function and decreasing MDSCs infiltration. This is the first study to develop peptides to block VISTA/PSGL-1 interaction, which could act as promising candidates for cancer immunotherapy.
ABSTRACT
Acute pancreatitis (AP) is a devastating disease characterized by an inflammatory disorder of the pancreas. P-selectin glycoprotein ligand-1 (PSGL-1) plays a crucial role in the initial steps of the adhesive at process to inflammatory sites, blockade of PSGL-1 might confer potent anti-inflammatory effects. In this study, we generated two non-human primate derived monoclonal antibodies capable of efficiently targeting human PSGL-1, RH001-6 and RH001-22, which were screened from immunized rhesus macaques. We found that RH001-6, can effectively block the binding of P-selectin to PSGL-1, and abolish the adhesion of leukocytes to endothelial cells in vitro. In vivo, we verified that RH001-6 relieved inflammatory responses and pancreatic injury in both caerulein and l-arginine induced AP models. We also evaluated the safety profile after RH001-6 treatment in mice, and verified that RH001-6 did not cause any significant pathological damages in vivo. Taken together, we developed a novel non-human primate derived PSGL-1 blocking antibody with high-specificity, named RH001-6, which can interrupt the binding of PSGL-1 and P-selectin and attenuate inflammatory responses during AP. Therefore, RH001-6 is highly potential to be further developed into therapeutics against acute inflammatory diseases, such as AP.
ABSTRACT
Objective To investigate the role and mechanism of PSGL-1 in development of salt-sensitive hypertension in mice. Methods PSGL-1 knockout(PSGL-1 -/-)and wild type(PSGL-1 +/ +)mice were fed a high salt (6% NaCl)or normal salt(0.4% NaCl)diet for three months. Blood pressure was measured under anesthesia via the carotid artery. The status of tissue inflammation and kidney injury was tested by flow cytometry, immunohistochemistry, and western blotting. Results Compared with mice fed a normal salt diet, PSGL-1 +/ +mice fed a high salt diet for three months showed high blood pressure, increased inflammatory cell infiltration in the aorta and skin, and increased inflammatory cytokine expression(interleukin-6, interleukin-1β, and tumor necrosis factor-α)in the kidney, as well as elevated expression of the kidney injury marker, connective tissue growth factor. In contrast, inflammation and kidney injury were not found in PSGL-1 -/-mice fed a high-salt diet. Conclusions In mice,PSGL-1 via inflammation plays a key role in development of hypertension and kidney injury caused by high salt intake.
ABSTRACT
Objective To investigate the effects of Ganlu Xiaodu Pills and its residues on PSGL-1 and proinflammatory cytokines in Coxsackie virus A16 (CoxA16) mouse model; To discuss its antiviral mechanism of action. Methods Totally 150 ICR mice at age of 7 days were randomly divided into normal group, model group, all-side group, aromatic residual group, clearing residual group and removing residual group, with 25 mice in each group. Except for normal group, other groups were injected intraperitoneally with 20 μL of 107TCID50 CoxA16 standard stock solution to establish models. Except for normal group and model group, other groups were given relevant medicine for intervention. The expressions of PSGL-1, TNF-α, IL-1β and IL-4 and histopathological observation were detected after 10 days of medication. Results Except for the normal group, the existence of a large number of CoxA16 in other groups of mouse muscle tissues proved successful modeling. HE staining showed that Ganlu Xiaodu Pills and residual could reduce damage to the muscle by CoxA16 virus. Compared with the normal group, the expression of PSGL-1 protein in the model group increased (P<0.01); compared with the model group, all-side group, aromatic residue group, clearing residual group, removing residual group inhibited the expression of PSGL-1 protein, reduced the inflammatory factors of TNF-α, IL-1β, and IL-4 (P<0.01). Conclusion Ganlu Xiaodu Pills and its residues have anti-inflammatory effects, and the all-side group shows the best efficacy.
ABSTRACT
Objective PSGL-1 is specifically expressed in leucocytes.The aim of this study was to explore the changes of myeloid-derived suppressor cells (MDSCs) in the spleen and bone marrow in PSGL-1-deficient mice.Methods PSGL-1 -/-mice were used in the experiment.After identification of the offsprings, flow cytometry was used to test the expression of CD11b and Gr-1 in C57 and PSGL-1 -/-mice.Results Compared with the C57 mice, the expression of MDSCs was up-regulated in the PSGL-1-deficient mice ( P <0.001).Conclusion The expression of MDSCs is upregulated in PSGl-1-deficient mice.
ABSTRACT
Purpose To investigate the location and distribution of EV71 receptors scavenger receptor class B member 2 ( SCARB2 ) and human P-selectin glycoprotein ligand-1 (PSGL-1) in lung tissues of fatal hand, foot and mouth disease (HFMD), healthy children and adults. Methods The expression of EV71 receptors SCARB2 and PSGL-1 was detected by using immunohistochemistry in lung tissues of 15 autopsies of HFMD, 3 of healthy children, 8 of healthy adults. Results SCARB2 distributed in bronchial, bronchioli ep-ithelia, alveolar epithelial cells and inflammatory cells among HFMD, healthy children and adults. No significant difference was noted of the positive rates of SCARB2 expression among these three groups (P>0. 05). PSGL-1 distributed in bronchial and bronchioli epi-thelium of adults, but no PSGL-1 expression was found in HFMD and healthy children. The positive rates of PSGL-1 were 100%, 0, 0 in bronchial and bronchioli epithelium among the three groups, respectively (P0. 05). Further, no PSGL-1 expression was observed in alveolar epithelia cells of all groups tested. Conclusions EV71 receptor SCARB2 distributes in bronchial, bronchioli, alveolar epithelial and inflammatory cells of HFMD. Meanwhile, PSGL-1 only distributes in inflammatory cells of HFMD, suggesting that SCARB2 possibly plays a role on HFMD infection.
ABSTRACT
Objective To observe the intervention effects of Xintongfang on the expression of P-selectin (PS), P-selectin glycoprotein ligand-1 (PSGL-1), platelet-leukocyte aggregates (PLA) and platelet-monocyte aggregates (PMA) in patients of coronary heart disease with carotid artery plaque. Methods Sixty patients were randomly divided into Xintongfang group and the control group, with 30 cases in each group. Xintongfang group was given Xintongfang, the control group was given aspirin and atorvastatin calcium for two months. The expression of PS, PSGL-1, PLA and PMA were tested by flow cytometry before and after treatment. Results The expression of PS, PSGL-1, PLA and PMA in two groups were reduced (P<0.01). Xintongfang group had more obvious effects on the expression of PLA and PMA than the control group (P<0.05). Conclusion Xintongfang can reduce the degree of inflammatory in patients of coronary heart disease with carotid artery plaque by inhibiting platelet-leukocyte interaction.