Phosphate-buffered Saline-treated Group Research Articles

CD91 Derived Treg Epitope Modulates Regulatory T Lymphocyte Response, Regulates Expression of Costimulatory Molecules on Antigen-Presenting Cells, and Rescues Pregnancy in Mouse Pregnancy Loss Model.

The loss of immune tolerance to fetal antigens may result in reproductive failure. The downregulated number and activity of T regulatory lymphocytes, which are critical for the establishment of immune tolerance to fetal antigens, during pregnancy may lead to miscarriage. The adoptive transfer of Tregs prevents fetal loss in abortion-prone mice. Recently, we demonstrated that the administration of tregitopes, which are short peptides found in human and mouse immunoglobulins (IgGs), decreased the incidence of abortions in female CBA/J mice mated with DBA/2J mice. Here, two non-IgG source peptides (SGS and LKD) that can potentially bind to the major histocompatibility complex II (MHC II) with high affinity and induce Treg expansion were designed in silico. The immune dysregulation-induced pregnancy failure mouse model was used to evaluate the effect of SGS and LKD on immune response and pregnancy outcome. The fetal death rate in the SGS-treated group was lower than that in the phosphate-buffered saline-treated group. SGS and LKD upregulated the splenic pool of Tregs and modulated the T-helper cell (Th1)/Th2-related cytokine response at the preimplantation stage. Additionally, SGS and LKD downregulated the expression of CD80 and MHC class II molecules in splenic CD11c+ antigen-presenting cells. Thus, SGS treatment can result in beneficial pregnancy outcomes. Additionally, SGS peptide-mediated immunomodulation can be a potential therapeutic strategy for immune dysregulation-induced pregnancy failure.

Amniotic fluid mesenchymal stem cells repair mouse corneal cold injury by promoting mRNA N4-acetylcytidine modification and ETV4/JUN/CCND2 signal axis activation

Severe corneal injury is one of the main causes of loss of visual function. Mesenchymal stem cells (MSCs) have the ability to repair damaged cells in vivo. The present study aimed to explore whether MSCs could function as a cell therapy tool to replace traditional methods to treat corneal injury. CD44 + /CD105 + mesenchymal stem cells isolated from mouse amniotic fluid (mAF-MSCs) were injected into mice after cryoinjury to induce corneal endothelial cell injury. Histopathological assays indicated that mAF-MSCs could promote the growth of corneal epithelial cells, reduce keratitis, and repair the corneal damage caused by low temperature. cDNA microarray analysis revealed that the mAF-MSCs affected the expression patterns of mRNAs related to cell proliferation and differentiation pathways in the mice after transplantation. The results of quantitative real-time PCR and western blotting revealed that NAT12, NAT10, and the ETV4/JUN/CCND2 signaling axis were elevated significantly in the mAF-MSC-transplantation group, compared with those in the phosphate-buffered saline-treated groups. High performance liquid chromatography–mass spectroscopy results revealed that mAF-MSCs could promote mRNA N4-acetylcytidine (ac4C) modification and high expression of N-acetyltransferase in the eyeballs. RNA immunoprecipitation-PCR results showed that a specific product comprising Vegfa, Klf4, Ccnd2, Jun, and Etv4 mRNA specific coding region sites could be amplified using PCR from complexes formed in mAF-MSC-transplanted samples cross-linked with anti-ac4C antibodies. Thus, mouse amniotic fluid MSCs could repair the mouse corneal cold injury by promoting the ETV4/JUN/CCND2 signal axis activation and improving its stability by stimulating N4-acetylcytidine modification of their mRNAs.

Adoptive cell therapy with induced regulatory T cells normalises the abortion rate in abortion-prone mice.

Ovarian hormones drive invivo generation of regulatory T cells (Tregs) during pregnancy. Little is known about the therapeutic potential of invitro hormone-derived Tregs in pregnancy loss. We investigated the effects of hormone-induced Tregs in a murine model of abortion. CD4+CD25- T cells were isolated from the spleens of CBA/J mice and stimulated with either 17β-oestradiol (E2), progesterone (P4) or transforming growth factor-β1 (TGFB1) plus retinoic acid (RA) for 4 days to generate induced Tregs (iTregs). On Days 1-4 of gestation, DBA/2-mated pregnant CBA/J female mice (abortion prone) were injected intravenously with iTregs or Tregs isolated from normal BALB/c-mated pregnant CBA/J mice (np-Tregs). On Day 14, the number of resorbed fetuses was assessed. Serum interferon (IFN)-γ and uterine forkhead box p3 (Foxp3) expression was analysed by ELISA and immunohistochemistry respectively. Using a 3H-thymidine incorporation assay, isolated CD4+CD25+ Tregs induced by the different treatments suppressed the proliferation of CD4+CD25- T cells. Adoptive transfer of iTregs (from all induction groups) significantly decreased fetal resorption in abortion-prone mice. There were no significant changes in serum IFN-γ concentrations after the adoptive transfer of iTregs or np-Tregs. Immunohistochemistry revealed significantly higher Foxp3 expression in gravid uteri from mice injected with np-Tregs and P4-induced iTregs than in the phosphate-buffered saline-treated group. The findings of this study indicate a potential therapeutic benefit of invitro-induced Tregs in patients with recurrent abortion.

A CpG-adjuvanted intranasal enterovirus 71 vaccine elicits mucosal and systemic immune responses and protects human SCARB2-transgenic mice against lethal challenge

Enterovirus 71 (EV71) is an aetiological agent responsible for seasonal epidemics of hand-foot-and-mouth disease, which causes considerable mortality among young children. Mucosal vaccines can efficiently induce secretory IgA at mucosal surfaces and thereby prevent or limit infection at the site of virus entry. CpG oligodeoxynucleotides (ODNs), which resemble bacterial DNA, can induce the innate immune response through activation of Toll-like receptor 9. Here, we used CpG ODNs as adjuvants to investigate an EV71 mucosal vaccine in mice. In the EV71 + CpG group, the EV71-specific IgG and IgA titres in the serum, nasal wash, bronchoalveolar lavage fluid, and faeces were substantially higher than those in the EV71- and phosphate-buffered saline-treated groups. Moreover, the number of EV71-specific IgG- and IgA-producing cells was also higher in the EV71 + CpG group. Furthermore, T-cell proliferative responses and interleukin-17 secretion were markedly increased when CpG-adjuvanted EV71 was delivered intranasally. More importantly, the induced antibodies neutralised infection by EV71 of the C2 genotype and crossneutralised infection by EV71 of the B4 and B5 genotypes. Lastly, human scavenger receptor class B, member 2-transgenic mice intranasally immunised with the CpG-adjuvanted EV71 vaccine resisted a subsequent lethal challenge with EV71, indicating that CpG was an effective intranasal adjuvant for EV71 mucosal-vaccine development.

Restoring cigarette smoke-induced impairment of efferocytosis in alveolar macrophages.

Cigarette smoke has been associated with susceptibility to different pulmonary and airway diseases. Impaired alveolar macrophages (AMs) that are major phagocytes in the lung have been associated with patients with airway diseases and active smokers. In the current report, we show that exposure to second-hand cigarette smoke (SHS) significantly reduced efferocytosis in vivo. More importantly, delivery of recombinant granulocyte-macrophage colony-stimulating factor (GM-CSF) to the alveolar space restored and refurbished the efferocytosis capability of AMs. Exposure to SHS significantly reduced expression of CD16/32 on AMs, and treatment with GM-CSF not only restored but also significantly increased the expression of CD16/32 on AMs. GM-CSF treatment increased uptake and digestion/removal of apoptotic cells by AMs. The latter was attributed to increased expression of Rab5 and Rab7. Increased efferocytosis of AMs was also tested in a disease condition. AMs from GM-CSF-treated, influenza-infected, SHS-exposed mice showed significantly better efferocytosis activity, and mice had significantly less morbidity compared with phosphate-buffered saline-treated group. GM-CSF-treated mice had increased amphiregulin levels in the lungs, which in addition to efferocytosis of AMs may have attributed to their protection against influenza. These results will have great implications for developing therapeutic approaches by harnessing mucosal innate immunity to treat lung and airway diseases and protect against pneumonia.

Induced pluripotent stem cells alleviate lung injury from mesenteric ischemia-reperfusion.

Mesenteric ischemia-reperfusion (I/R) injury is a serious pathophysiologic process that can trigger the development of multiorgan dysfunction. Acute lung injury is a major cause of death among mesenteric I/R patients, as current treatments remain inadequate. Stem cell-based therapies are considered novel strategies for treating several devastating and incurable diseases. This study examined whether induced pluripotent stem cells (iPSCs) lacking c-myc (i.e., induced using only the three genes oct4, sox2, and klf4) can protect against acute lung injury in a mesenteric I/R mouse model. C57BL/6 mice were randomly divided into the following groups: sham/no treatment, vehicle treatment with phosphate-buffered saline, treatment with iPSCs, and treatment with iPSC-conditioned medium. The mice were subjected to mesenteric ischemia for 45 minutes followed by reperfusion for 24 hours. After I/R, the lungs and the ileum of the mice were harvested. Lung injury was evaluated by histology, immunohistochemistry, and analyses of the levels of inflammatory cytokines, cleaved caspase 3, and 4-hydroxynonenal. The intravenously delivered iPSCs engrafted to the lungs and the ileum in response to mesenteric I/R injury. Compared with the phosphate-buffered saline-treated group, the iPSC-treated group displayed a decreased intensity of acute lung injury 24 hours after mesenteric I/R. iPSC transplantation significantly reduced the expression of proinflammatory cytokines, oxidative stress markers, and apoptotic factors in injured lung tissue and remarkably enhanced endogenous alveolar cell proliferation. iPSC-conditioned medium treatment exerted a partial effect compared with iPSC treatment. When considering the anti-inflammatory, antioxidant, and antiapoptotic properties of iPSCs, the transplantation of iPSCs may represent an effective treatment option for mesenteric I/R-induced acute lung injury.

Hepatocyte Growth Factor Gene-Modified Mesenchymal Stem Cells Augment Sinonasal Wound Healing.

This study was designed to investigate the effects of hepatocyte growth factor (HGF) transgenic mesenchymal stem cells (HGF-MSCs) on wound healing in the sinonasal mucosa and nasal epithelial cells (NECs). We also sought to determine whether HGF-MSCs and MSCs can migrate into the injured mucosa and differentiate into ciliated cells. Human HGF-overexpressing umbilical cord MSCs (hHGF-UCMSCs) were established, and upregulation of hHGF expression was confirmed by real-time PCR (RT-PCR) and enzyme-linked immunosorbant assay (ELISA). To investigate the paracrine effect of human MSCs (hMSCs) on nasal epithelial repair, hMSC- and HGF-MSC-conditioned media (CM) were used in NEC proliferation assays and in an in vitro scratch-wound repair model. The in vivo sinonasal wound-healing model was established, and all enrolled rabbits were randomly assigned to four groups: the GFP-MSC group, the HGF-MSC group, the Ad-HGF group, and the surgery control group. The average decreased diameter was recorded, and the medial wall of the maxillary sinus was removed for histological analysis and scanning electron microscopy. Collagen deposition in the wound tissue was detected via Masson trichrome (M&T) staining. The distribution of MSCs and HGF-MSCs was observed by immunofluorescence. MSCs improved nasal wound healing both in vivo and in vitro. HGF overexpression in MSCs augmented the curative effects. Reduced collagen deposition and transforming growth factor beta1 (TGF-β1) expression were detected in the HGF-MSC group compared with the MSC-, Ad-HGF-, and phosphate-buffered saline-treated groups based on M&T staining and ELISA. The enhanced therapeutic effects of HGF-MSCs were accompanied by decreased level of the fibrogenic cytokine TGF-β1. In addition, both HGF-MSCs and MSCs can migrate to the injured mucosa and epithelial layer.

Natriuretic peptide clearance receptor ligand (C-ANP4-23 ) attenuates angiogenesis in a murine sponge implant model.

Natriuretic peptide receptor-C activation by the synthetic ligand C-ANP-4-23, a specific agonist for this receptor, has been shown to inhibit key events of the angiogenic cascade, such as migration, proliferation and vascular endothelial growth factor (VEGF) production. In the present study we investigated whether C-ANP4-23 could also inhibit angiogenesis in the sponge model in vivo. To this end, we evaluated the effects of C-ANP4-23 on inflammatory and angiogenic components of the fibrovascular tissue induced by polyether polyurethane sponge implants in mice. Measurements of the haemoglobin content (μg/mg wet tissue) and blood flow (laser Doppler perfusion imaging) of the implants, used as an index of vascularization, revealed that single (200ng) or multiple (200ng/day, 5days) doses of C-ANP4-23 reduced angiogenesis in the implants relative to the phosphate-buffered saline-treated group. The peptide exerted an inhibitory effect on nitric oxide production (nitrite levels) and had a dual effect on VEGF levels, depending on the number of doses (i.e. stimulation at 4days after one dose; inhibition at 7days after five doses). Histological analysis corroborated the biochemical and functional parameters indicative of inhibition of neovascularization (decreased vessel number) by C-ANP4-23 . The peptide failed to modulate inflammation in our system. The inhibitory effect of C-ANP4-23 on the angiogenic component of the fibrovascular tissue induced by the synthetic matrix extends the range of the its actions and may indicate its therapeutic potential in controlling angiogenesis in fibroproliferative diseases.

Substance P affects growth factors in Pseudomonas aeruginosa-infected mouse cornea.

This study analyzed the influence of substance P (SP) on growth factors related to wound healing in mice in the presence of infectious keratitis. Naturally resistant mice were injected intraperitoneally with SP or phosphate-buffered saline and infected with Pseudomonas aeruginosa, and corneal messenger RNA (mRNA) levels of growth factors and apoptosis genes were tested. Enzyme-linked immunosorbent assay determined the protein levels, whereas immunohistochemistry tested the distribution, macrophage phenotype, and cell quantitation. In vitro, macrophages were stimulated with lipopolysaccharide (LPS; with or without SP) and mRNA levels of proinflammatory and antiinflammatory cytokines and apoptosis genes were tested. After SP, epidermal growth factor mRNA and protein levels were disparately regulated early, with no differences later in the disease. Hepatocyte growth factor and fibroblast growth factor-7 mRNA and protein levels were increased after SP treatment. Enumerating dual-labeled stromal cells revealed no difference between SP-treated versus phosphate-buffered saline-treated groups in the percentage of epidermal growth factor-labeled fibroblasts or macrophages, but there were significant increases in both hepatocyte growth factor- and fibroblast growth factor-7-labeled cells. Type 2 (M2) macrophages and caspase-3 mRNA levels were decreased, whereas B-cell lymphoma-2 mRNA expression was increased after SP treatment. In vitro, mRNA levels of several proinflammatory cytokines and B-cell lymphoma-2 were elevated, whereas transforming growth factor β was decreased after macrophage stimulation with SP (with LPS) over LPS alone. (Mice: n = 105 control; 105 experimental.) These data show that treatment with SP in infectious keratitis elevates growth factors but also adversely affects the disease by enhancing the inflammatory response and its sequelae.

Human Deciduous Teeth Dental Pulp Cells With Basic Fibroblast Growth Factor Enhance Wound Healing of Skin Defect

In this research, we examined the effect on wound healing applying basic fibroblast growth factor (b-FGF) that is approved for clinical use to enhance wound healing and human deciduous teeth dental pulp cells (hDPCs) in clinics, but that have been attracting attention as a novel stem cell source in recent years. Human deciduous teeth were harvested from healthy volunteers, and hDPCs were isolated. We used a nude mouse full-thickness skin defect model and evaluated wound healing by macroscopic view and histologic and histomorphometric analysis. The mice were randomly divided into 4 groups: phosphate-buffered saline-treated group (control group), b-FGF-treated group (b-FGF group), hDPC-treated group (hDPC group), and hDPC and b-FGF-treated group (hDPC/b-FGF group). Basic fibroblast growth factor and hDPC groups accelerated wound healing compared with the control group. There was no statistically significant difference in wound healing observed between the hDPC and b-FGF groups. The hDPC/b-FGF group demonstrated accelerated wound healing compared with other groups. At day 14, PKH26-positive cells were surrounded by human type I collagen in hDPC and hDPC/b-FGF groups in immunohistologic evaluation. Significantly increased collagen fibril areas in wound tissues were observed in b-FGF, hDPC, and hDPC/b-FGF groups as compared with the control group at days 7 and 14. Our results showed that the hDPC/b-FGF group significantly promotes wound healing compared with other groups. This study implies that deciduous teeth that are currently considered as medical spare parts might offer a unique stem cell resource for potential of new cell therapies for wound healing in combination with b-FGF.

Roles of Macrophages in Flow-Induced Outward Vascular Remodeling

Sustained hemodynamic stresses, especially sustained high blood flow, result in flow-induced outward vascular remodeling. Mechanisms that link hemodynamic stresses to vascular remodeling are not well understood. Inflammatory cells, known for their release of proteinases, including matrix metalloproteinases (MMPs), are emerging as key mediators for various tissue remodeling. Using a flow-augmented common carotid artery model in rats, we tested whether macrophages play critical roles in adaptive outward vascular remodeling in response to an increase in blood flow. Left common carotid artery ligation caused a sustained increase in blood flow with a gradual increase in luminal diameter in the right common carotid artery. Macrophages infiltrated into the vascular wall that peaked 3 days after flow augmentation. The time course of MMP-9 expression coincided with infiltration of macrophages. Macrophage depletion by liposome-encapsulated dichloromethylene diphosphonate significantly reduced flow-induced outward vascular remodeling, as indicated by the smaller luminal diameter of flow-augmented right common carotid artery in the clodronate-treated group compared with the phosphate-buffered saline-treated group (P<0.05). These data show critical roles of macrophages in flow-induced outward vascular remodeling. Inflammatory cell infiltration and their subsequent release of cytokines may be key processes for flow-induced outward vascular remodeling.

The effects of colchicine treatment on wound healing in a caustic murine injury model.

The present study determined the effects of colchicine on wound repair in a murine model of dermal chemical injury. Standardized 4.15 cm2 circular lesions were induced on the dorsum of adult male mice with NaOH. Five minutes of IN or 3N caused lesions of graded depth. Mice received colchicine (1 mg/kg) or phosphate-buffered saline intraperitoneally in equivalent volumes. Treatment began immediately postinjury and was continued on an alternating day schedule for 14 days. Wound size was measured every third day postinjury. On day 15 postinjury, wounds were histologically graded for depth of injury, degree of fibrosis, inflammatory cell response, and revascularization. All histological determinations and wound measurements were performed in a blinded fashion. All mice had a similar initial wound size and completed the experimental protocol. In dermal wounds of superficial depth, colchicine-treated mice (n = 20) had a larger wound size during days 6 through 9 of the experimental trial when compared to phosphate-buffered saline-treated mice (n = 18). In the deeper wounds, there were no significant differences in wound size between colchicine and phosphate-buffered saline-treated groups. Colchicine (n = 54) did not affect the degree of fibrosis at all depths of injury vs phosphate-buffered saline treatment in mice (n = 55). The degree of wound revascularization was less in colchicine-treated mice (n = 54) than phosphate-buffered saline-treated mice (n = 55). Colchicine did not improve wound healing in an alkaline-induced dermal injury.