Anti-inflammatory protein tumor necrosis factor-α-stimulated protein 6 (TSG-6) promotes early gingival wound healing: an in vivo study

Effects of Release of TSG-6 from Heparin Hydrogels on Supraspinatus Muscle Regeneration

Muscle degeneration after rotator cuff tendon tear is a significant clinical problem. In these experiments, we developed a poly(ethylene glycol)-based injectable granular hydrogel containing two heparin derivatives (fully sulfated (Hep) and fully desulfated (Hep-)) as well as a matrix metalloproteinase-sensitive peptide to promote sustained release of Tumor Necrosis Factor Stimulated Gene 6 (TSG-6) over 14+ days in vivo in a rat model of rotator cuff muscle injury. The hydrogel formulations demonstrated similar release profiles in vivo , thus facilitating comparisons between delivery from heparin derivatives on level of tissue repair in two different areas of muscle (near the myotendious junction (MTJ) and in the muscle belly (MB)) that have been shown previously to have differing responses to rotator cuff tendon injury. We hypothesized that sustained delivery of TSG-6 would enhance the anti-inflammatory response following rotator cuff injury through macrophage polarization, and that release from a fully sulfated heparin derivative (Hep) would potentiate this effect throughout the muscle. Inflammatory/immune cells, satellite cells, and fibroadipogenic progenitor cells, were analyzed by flow cytometery 3 and 7 days after injury and hydrogel injection, while metrics of muscle healing were examined via immunohistochemistry up to Day 14. Results showed controlled delivery of TSG-6 from Hep caused heightened macrophage response (Day 14 macrophages, 4.00 ± 1.85% single cells, M2a, 3.27 ± 1.95% single cells) and increased markers of early muscle regeneration (embryonic heavy chain staining) by Day 7, particularly in the MTJ region of the muscle, compared to release from desulfated heparin hydrogels. This work provides a novel strategy for localized, controlled delivery of TSG-6 to enhance muscle healing after rotator cuff tear.

IMPACT STATEMENT

Rotator cuff tear is a significant problem that can cause muscle degeneration. In this study, a hydrogel particle system was developed for sustained release of an anti-inflammatory protein, Tumor Necrosis Factor Stimulated Gene 6 (TSG-6), to injured muscle. Release of the protein from a fully sulfated heparin hydrogel-based carrier demonstrated greater changes in amount inflammatory cells and more early regenerative effects than a less-sulfated carrier. Thus, this work provides a novel strategy for localized, controlled delivery of an anti-inflammatory protein to enhance muscle healing after rotator cuff tear.

The effect of an antioxidant gel compared to chlorhexidine during the soft tissue healing process: An animal study

BACKGROUND

Prolonged inflammation and oxidative stress can impede healing. To enhance healing efficiency, many solutions have been employed. This is an in vivo study comparing chlorhexidine (CHX) to a commercial antioxidant gel (AO).

METHODS

Envelope flaps were created in the lower incisor gingival region of 60 Sprague-Dawley rats, and acellular dermal matrix (ADM) was inserted. Animals were randomly assigned to postsurgical treatment application of AO gel or 0.12% CHX twice daily. A control group received no postsurgical treatment. Data collected (before surgery, 24 h, and 72 h) included surgical images, tissue samples, and weights. Blinded scorers assessed images using a wound healing scale. Real-time polymerase chain reaction (RT-PCR) was used for gene expression of tumor necrosis factor-alpha (TNFα), interleukin-1 (IL-1), myeloperoxidase (MPO), and superoxide dismutase (SOD).

RESULTS

The AO group scored higher than the CHX and control groups in clinical evaluation (p < 0.05). At 24 h, TNFα expression was upregulated in the AO group compared to CHX (p = 0.027) and controls (p = 0.018). The AO group had significantly higher expression of antioxidant enzyme (SOD) at 24 h compared to CHX (p = 0.021). All animals lost weight in the first 24 h. Animals treated with AO or CHX regained more weight at 72 h than control animals (p = 0.034 and 0.003, respectively).

CONCLUSION

Animals treated with AO healed faster. AO led to earlier upregulation of TNFα and antioxidant enzyme SOD. We hypothesized that AO promoted an earlier inflammatory process while counteracting oxidative stress by increasing antioxidant responses via SOD.

Polarization of human gingival fibroblasts by Th1-, Th2-, Th17-, and Treg-derived cytokines

BACKGROUND AND OBJECTIVE

The purpose of this study was to evaluate whether gingival fibroblasts (GFs) can be differently activated and polarized into distinct functional subtypes by T-helper (Th) cytokines.

METHODS

Gingival fibroblasts were stimulated with interferon (IFN)-γ, interleukin (IL)-4, IL-17, and transforming growth factor (TGF)-β, representative cytokines of Th1, Th2, Th17, and regulatory T cells, respectively, and the gene expression profiles were analyzed by microarray. Differentially expressed genes (DEGs) in GFs stimulated by 4 cytokines were screened, and a gene ontology (GO) analysis of the DEGs was conducted. To confirm the reliability of the microarray results, the DEGs that showed the largest differences compared with non-stimulated GFs were further analyzed by RT-PCR. To evaluate the effect of polarization on GFs responses to lipopolysaccharide (LPS), GFs stimulated by 4 cytokines were further stimulated with Escherichia coli LPS and mRNA levels of several genes were analyzed using RT-PCR.

RESULTS

Differentially expressed genes by 4 Th cytokines were enriched in different GO terms, and the patterns of gene expression on GFs were shown functionally different. GFs stimulated with IFN-γ (GF(IFN-γ)) up-regulated the expression of chemokines (chemokine (C-X-C motif) ligand (CXCL)9, -10, -11, chemokine (C-C motif) ligand (CCL)8), molecules involved in antigen presentation, complement component 3 (C3), and other immune response-related molecules, whereas they down-regulated the expression of several types of collagen, extracellular matrix (ECM) components, and DNA replication and nuclear protein-related molecules. By contrast, GF(IL-4) up-regulated the expression of ECM components, cell adhesion molecules, and tissue development-related molecules and down-regulated the expression of chemokines (CXCL10 and CXCL8) and adaptive immune response-related molecules. GF(IL-17) up-regulated the expression of chemokines and other molecules for neutrophil infiltration and activation, the pro-inflammatory cytokine IL-6, and C3. GF(TGF-β) up-regulated the expression of cell growth-related molecules, ECM components, several types of collagen, and cell adhesion molecules and down-regulated the expression of molecules related to complement activation and bacterial recognition. GFs stimulated by 4 cytokines responded differently to LPS.

CONCLUSION

These results show that Th cytokines can polarize GFs into cells with functionally distinct features: immune-activating but tissue-destructive GF(IFN-γ), tissue-reparative, and immune-inhibiting GF(IL-4), highly pro-inflammatory GF(IL-17), and potent tissue-reparative GF(TGF-β).

Recombinant TSG-6 protein inhibits the growth of capsule fibroblasts in frozen shoulder via suppressing the TGF-β/Smad2 signal pathway

Background

The tumor necrosis factor-stimulated gene-6 (TSG-6) has been confirmed to inhibit inflammation. It is now generally accepted that local inflammatory stimulation around shoulder capsule causes proliferative fibrosis. This study aims to investigate the mechanism of recombinant TSG-6 protein inhibiting the growth of capsule fibroblasts in frozen shoulder via the TGF-β/Smad2 signal pathway.

Methods

Human frozen shoulder capsule tissue was taken for primary and passage culture, and the 3rd generation fibroblasts from pathological frozen shoulder capsule were treated with different concentrations of recombinant TSG-6 protein, or with TGF-β1 agonist SRI-011381. Immunoconfocal analysis was used to identify the isolated fibroblasts, and MTT assay, colony formation assay, and flow cytometry were used to detect the viability, proliferation, and apoptosis rate of fibroblast. The contents of fibrosis and inflammation indexes COL1A1, TNF-α, IL-6, and IL-1β in the cell supernatant were detected using ELISA and then further examined by qRT-PCR. The expression of Bax, Bcl-2, and proteins related to TGF-β/Smad2 pathway were detected by Western Blot.

Results

Compared with the blank control group, fibroblasts intervened with TSG-6 (2 μg and 5 μg) showed significantly decreased viability and proliferation ability and enhanced cell apoptosis, concurrent with the reductions in Bcl-2 expression; COL1A1, TNF-α, IL-6, and IL-1β levels; and the expression of TGF-β1 and phosphorylated Smad22, and an increase in Bax expression, while SRI-011381 treatment would reverse the effect of recombinant TSG-6 protein.

Conclusion

Recombinant TSG-6 protein inhibited the growth of primary fibroblasts from human frozen shoulder capsule by suppressing the TGF-β/Smad2 signaling pathway.

Down-Regulation of miR-301a-3p Reduces Burn-Induced Vascular Endothelial Apoptosis by potentiating hMSC-Secreted IGF-1 and PI3K/Akt/FOXO3a Pathway

Vascular endothelium dysfunction plays a pivotal role in the initiation and progression of multiple organ dysfunction. The mesenchymal stem cell (MSC) maintains vascular endothelial barrier survival via secreting bioactive factors. However, the mechanism of human umbilical cord MSC (hMSC) in protecting endothelial survival remains unclear. Here, we found IGF-1 secreted by hMSC suppressed severe burn-induced apoptosis of human umbilical vein endothelial cells (HUVECs) and alleviated the dysfunction of vascular endothelial barrier and multiple organs in severely burned rats. Severe burn repressed miR-301a-3p expression, which directly regulated IGF-1 synthesis and secretion in hMSC. Down-regulation of miR-301a-3p decreased HUVECs apoptosis, stabilized endothelial barrier permeability, and subsequently protected against multiple organ dysfunction in vivo. Additionally, miR-301a-3p negatively regulated PI3K/Akt/FOXO3 signaling through IGF-1. Taken together, our study highlights the protective function of IGF-1 against the dysfunction of multiple organs negatively regulated by miR-301a-3p, which may provide the theoretical foundation for further clinical application of hMSC.

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IGF-1 secreted by hMSC suppressed severe burn-induced apoptosis of HUVECs

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miR-301a-3p directly regulated IGF-1 synthesis and secretion in hMSC

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DomiR-301a-3p protected against multiple organ dysfunction

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miR-301a-3p regulated PI3K/Akt/FOXO3 signaling through hMSC-secreted IGF-1

Cutaneous Wounds in Mice Lacking TSG-6 Exhibit Delayed Closure and an Abnormal Inflammatory Response

We investigated how loss of TSG-6 affects wound closure and skin inflammation. TSG-6 has several known biological functions, including the enzymatic transfer of heavy-chain proteins from inter-α-trypsin inhibitor to hyaluronan to form heavy-chain protein-hyaluronan complexes. TSG-6 and heavy-chain protein-hyaluronan are constitutively expressed in normal skin and increase post-wounding but are completely absent in TSG-6-null mice. Wound closure rates are significantly delayed in TSG-6-null mice relative to wildtype mice. Neutrophil recruitment is delayed in early wounds (12 hours and day 1), whereas late wounds (day 7) show elevated neutrophil accumulation. In addition, granulation phase resolution is delayed, with persistent blood vessels and reduced dermal collagen at 10 days. The proinflammatory cytokine TNFα is elevated >3-fold in unwounded TSG-6-null skin and increases further after wounding (from 12 hours to 7 days) before returning to baseline by day 10. Other cytokines examined, such as IL-6, IL-10, and monocyte chemotactic protein-1, showed no consistent differences. Reintroduction of TSG-6 into TSG-6-null wounds rescues both the delay in wound closure and the aberrant neutrophil phenotype. In summary, our study indicates that TSG-6 plays an important role in regulating wound closure and inflammation during cutaneous wound repair.

An evaluation of the effects of caffeic acid phenethyl ester and Ankaferd blood stopper on secondary wound healing of oral mucosal tissue

Background/aim

Caffeic acid phenethyl ester (CAPE) and Ankaferd Blood Stopper (ABS) are considered to contribute to wound healing. The purpose of this study was to investigate the effect of ABS and CAPE on secondary wound healing of oral mucosal tissue.

Materials and methods

In total, 63 male Sprague-Dawley rats were used in this study. The animals were randomly divided into three groups and anaesthetized with ketamine (8 mg/100 g, intraperitoneally): a control group, CAPE group, and ABS group. A full-thickness excisional wound was created using a 4 mm punch biopsy tool. Topical ABS and CAPE were then applied in each group for 7, 14, and 21 days (n = 7 in each group). The animals in each group were sacrificed after 7, 14, and 21 days. Palatal specimens were stained with haematoxylin-eosin. Vascular endothelial growth factor (VEGF) and tumour necrosis factor-inducible gene 6 (TSG-6) protein expressions were determined using the Western blot method.

Results

Inflammation, vessel dilatation, and haemorrhages were significantly lower in the CAPE group as compared with these parameters in the other groups (P < 0.05). Fibrosis was significantly higher in the ABS group as compared with that in the other groups (P < 0.05). VEGF protein levels were elevated in the 21-day CAPE group and 7-day ABS group. The expression of TSG-6 increased in the 7-day CAPE group and 21-day ABS group.

Conclusion

Based on our findings, ABS and CAPE had positive effects on the oral wound healing process.

A wheat germ-derived peptide YDWPGGRN facilitates skin wound-healing processes

Wheat germ derivatives have been shown to inhibit inflammation-related diseases. In this study, a small peptide (YDWPGGRN) isolated from wheat germ was used to study its anti-inflammatory activity and its application in skin wound healing. Both the in vitro and in vivo results clearly showed that YDWPGGRN significantly inhibited the LPS-stimulated NO, IL-1β, IL-6 and TNF-α production but promoted the release of an anti-inflammatory cytokine, IL-10. In addition, YDWPGGRN directly enhanced the proliferation and migration of HaCaT cells and L929 cells. Furthermore, the results demonstrated that YDWPGGRN was able to stimulate angiogenesis and collagen production in wound areas, consequently accelerating the skin wound-healing processes in a rat model with a full thickness dermal wound. The current findings suggest that YDWPGGRN promotes wound healing by anti-inflammatory reactions and enhances the proliferation and migration of keratinocytes and fibroblasts; therefore, it may be applicable for skin wound therapeutics.

TSG-6 Inhibits Oxidative Stress and Induces M2 Polarization of Hepatic Macrophages in Mice With Alcoholic Hepatitis via Suppression of STAT3 Activation

Tumor necrosis factor (TNF)-α-stimulated protein 6 (TSG-6) is a secreted protein with diverse tissue protective and anti-inflammatory properties. We aimed to investigate its effective in treating mice with alcoholic hepatitis (AH) and the associated mechanisms. AH was induced in 8-10 week female C57BL/6N mice by chronic-binge ethanol feeding for 10 days. Intraperitoneal (i.p.) injection of recombinant mouse TSG-6 or saline were performed in mice on day 10. Blood samples and hepatic tissues were collected on day 11. Biochemistry, liver histology, flow cytometry, and cytokine measurements were conducted. Compared to the normal control mice, the AH mice had significantly increased liver/body weight ratio, serum alanine aminotransferase (ALT) and aspartate aminotransferases (AST), hepatic total cholesterol (TC), triglyceride (TG), malondialdehyde (MDA), hepatic macrophage infiltration, serum and hepatic interleukin (IL)-6, and tumor necrosis factor (TNF)-α, which were markedly reduced by i.p. injection of rmTSG-6. Compared to the normal control mice, the hepatic glutathione (GSH), accumulation of M2 macrophages, serum, and hepatic IL-10 and TSG-6 were prominently reduced in the AH mice, which were significantly enhanced after i.p. injection of rmTSG-6. Compared to the normal control mice, hepatic activation of signal transducer and activator of transcription 3 (STAT3) was significantly induced, which was markedly suppressed by rmTSG-6 treatment. TSG-6 were effective for the treatment of AH mice, which might be associated with its ability in inhibiting hepatic oxidative stress and inducing hepatic M2 macrophages polarization via suppressing STAT3 activation.

Immunomodulatory properties of dental tissue-derived mesenchymal stem cells: Implication in disease and tissue regeneration

Mesenchymal stem cells (MSCs) are considered as an attractive tool for tissue regeneration and possess a strong immunomodulatory ability. Dental tissue-derived MSCs can be isolated from different sources, such as the dental pulp, periodontal ligament, deciduous teeth, apical papilla, dental follicles and gingiva. According to numerous in vitro studies, the effect of dental MSCs on immune cells might depend on several factors, such as the experimental setting, MSC tissue source and type of immune cell preparation. Most studies have shown that the immunomodulatory activity of dental MSCs is strongly upregulated by activated immune cells. MSCs exert mostly immunosuppressive effects, leading to the dampening of immune cell activation. Thus, the reciprocal interaction between dental MSCs and immune cells represents an elegant mechanism that potentially contributes to tissue homeostasis and inflammatory disease progression. Although the immunomodulatory potential of dental MSCs has been extensively investigated in vitro, its role in vivo remains obscure. A few studies have reported that the MSCs isolated from inflamed dental tissues have a compromised immunomodulatory ability. Moreover, the expression of some immunomodulatory proteins is enhanced in periodontal disease and even shows some correlation with disease severity. MSC-based immunomodulation may play an essential role in the regeneration of different dental tissues. Therefore, immunomodulation-based strategies may be a very promising tool in regenerative dentistry.

Hyaluronan Accelerates Intestinal Mucosal Healing through Interaction with TSG-6

Hyaluronan (HA) has proven to be beneficial in the treatment of several diseases. Recently, it has been shown that the local application of HA (IBD98E) improves endoscopic and clinical outcomes in subjects with active distal ulcerative colitis (UC). However, the mechanisms by which this polysaccharide exerts its beneficial effects are unclear. Here, we demonstrated that HA treatment in vitro and in vivo improved mucosal healing by accelerating intestinal epithelial regeneration. Indeed, mice treated with HA showed a faster recovery from colitis and reduced endoscopic signs of mucosal inflammation compared to those receiving saline. Furthermore, histological analysis revealed less ulcerated mucosa in mice treated with HA, characterized by re-epithelialized areas. TSG-6, the secreted product of TNF-stimulated gene-6, is an HA-binding protein shown previously to have tissue-protective properties and promote wound healing. Mucosal levels of TSG-6 increased in UC patients compared to the healthy controls and also after wounding in mice. TSG-6 deletion prevented the beneficial properties of HA in mucosal wound repair, suggesting that the interaction of HA with TSG-6 is crucial for intestinal epithelial regeneration. Overall these results are consistent with HA having a therapeutic effect via the promotion of mucosal healing in patients with ulcerative colitis.

Ligustrazine nanoparticles nano spray's activation on Nrf2/ARE pathway in oxidative stress injury in rats with postoperative abdominal adhesion

Background

Postoperative abdominal adhesions formation is considered a significant clinical entity implicating the healing process following major pelvic and abdominal surgery, with serious clinical complications and need for substantial health care expenditures. However, setting a physical barrier between the damage site and the neighboring tissues is a convenient and highly valid way to minimize or prevent peritoneal adhesions. The present experimental study evaluated the preventive effect of ligustrazine nanoparticles nano spray (LNNS) on postoperative abdominal adhesion in rats and explored its mechanism.

Methods

Sixty male Sprague Dawley (SD) rats were randomly divided into sham operation group, control group, sodium hyaluronate group and low, medium, and high dose LNNS groups. All groups were prepared with abdominal adhesion models except for the sham operation group. The models were made by opening the abdominal cavity to and filing the serosa in ileocecal junction. The abdominal cavity of rats in the sham operation group were only opened and sutured. The wound surface of rats in the sodium hyaluronate group, low, medium, and high dose LNNS groups were sprayed with sodium hyaluronate gel (0.5 mL/kg) and LNNS (2.5, 5, and 10 mL/kg). Rats in each group were sacrificed 7 days later. Degree of adhesion was evaluated by naked eyes and the pathological sections were scored afterwards. The collagen synthesis in adhesion tissues was detected by Masson's trichrome stain, and the activities of reactive oxygen species (ROS), nitric oxide (NO), superoxide dismutase (SOD) and malondialdehyde (MDA) in peritoneal fluid were detected with the method of chromogenic substrate. Levels of TNF-α and IL-1β in serum, and the protein levels of MCP-1 and MMP-9 in adhesion tissues were detected by ELISA and. immunohistochemistry respectively. RT-PCR and Western blot were utilized to identify the expression levels of Nrf2, heme-oxygenase-1, NQO1 mRNA and protein in adherent intestinal tissues.

Results

Compared with the control group, the incidence of postoperative abdominal adhesions decreased in the low, medium and high dose LNNS groups, while the expression of SOD in the peritoneal fluid significantly increased. The expression levels of ROS, MDA and NO were reduced remarkably (P<0.05), so were the expression levels of serum TNF-α and IL-1β (P<0.01) and the expression of MCP-1 protein in adhesion tissues. The MMP-9 protein expression, and Nrf2, heme-oxygenase-1, NQO1 mRNA and protein expressions increased.

Conclusions

LNNS with medium or high dose can significantly reduce the incidence of postoperative abdominal adhesions, the mechanism of which may be the activation of Nrf2/ARE pathway, resulting in the up-regulation of Nrf2, heme-oxygenase-1, NQO1 and mRNA expression, as well as the levels of TNF-α and IL-1β in peripheral blood and the expression of MCP-1 protein in adhesion tissues. Meanwhile, the content of MMP-9 protein in adhesion tissues were raised, and oxidative stress and inflammatory response are released.

First Insights Into the M2 Inflammatory Response After Adipose-Tissue-Derived Stem Cell Injections in Radiation-Injured Muscles

The cutaneous radiation syndrome is the clinical consequence of local high-dose irradiation. It is characterized by extensive inflammation, necrosis, and poor revascularization of the skin, resulting in muscle inflammation and fibrosis. Based on these physiopathological processes, subcutaneous injections of adipose-tissue-derived stem/stromal cells have shown favorable effects on skin-wound healing in a minipig model of cutaneous radiation syndrome, in which muscle fibrosis persisted. Since fibrosis is mainly due to the inflammatory processes that often affect underlying tissues as well, the beneficial effects of intramuscular injections of adipose-tissue-derived stem/stromal cells on tissue recovery were evaluated. The polarization of the inflammatory response of irradiated muscle in a minipig model of cutaneous radiation syndrome was determined after acute local irradiation with 50 Gy gamma rays in a preliminary study (six minipigs). Analysis of the main inflammatory cytokines of the inflammatory response M1 (IL-1-beta and IL-6) and M2 (IL-10 and TGF-beta) by western blotting and in situ hybridization, as well as analysis of CD80/CD206 M1/M2 macrophage-specific markers by immunohistochemistry on minipig muscle samples, was performed 76 d after irradiation. The treatment of irradiated muscles with autologous adipose-tissue-derived stem/stromal cells led to an increase in IL-10 and TGF-beta, being associated with an increase in CD68+/CD206+ cells in this area. This highlights a polarization of M2 in the inflammatory response and indicates that adipose-tissue-derived stem/stromal cells may direct the irradiated tissues' inflammatory response towards a proregenerative outcome.

TSG-6: A multifunctional protein with anti-inflammatory and tissue-protective properties

Tumor necrosis factor- (TNF) stimulated gene-6 (TSG-6) is an inflammation-associated secreted protein that has been implicated as having important and diverse tissue protective and anti-inflammatory properties, e.g. mediating many of the immunomodulatory and beneficial activities of mesenchymal stem/stromal cells. TSG-6 is constitutively expressed in some tissues, which are either highly metabolically active or subject to challenges from the environment, perhaps providing protection in these contexts. The diversity of its functions are dependent on the binding of TSG-6 to numerous ligands, including matrix molecules such as glycosaminoglycans, as well as immune regulators and growth factors that themselves interact with these linear polysaccharides. It is becoming apparent that TSG-6 can directly affect matrix structure and modulate the way extracellular signalling molecules interact with matrix. In this review, we focus mainly on the literature for TSG-6 over the last 10 years, summarizing its expression, structure, ligand-binding properties, biological functions and highlighting TSG-6's potential as a therapeutic for a broad range of disease indications.

Infliximab relieves blood retinal barrier breakdown through the p38 MAPK pathway in a diabetic rat model

AIM

To clarify the mechanism of infliximab treatment in diabetic macular edema (DME) and to provide a new alternative therapy for DME.

METHODS

Rats were randomly divided into the control group, the model group and the infliximab treatment group. A diabetic rat model was created. The concentration of TNF-α in the vitreous body was detected by ELISA. The expressions of B-Raf, p38, claudin-1 and occludin in the retina were detected by Western blot. The integrity of the blood retinal barrier (BRB) was measured using Evan's blue as a tracer.

RESULTS

After three months and six months of the diabetes model, the vitreous TNF-α level in the model group was higher than that of the control group. It was also higher in treated group than that of the control group but was lower than that of the model group. The differences among the three groups were statistically significant (at 3mo, F=857.098, P<0.001; 6mo, F=1261.897, P<0.001). The retina B-Raf and p38 levels in the model group were higher than that of the control group. They were also higher in treated group than that of the control group but were lower than that of the model group. The differences among the three groups were statistically significant (B-Raf at 3mo, F=106.596, P<0.001 and at 6mo, F=200.681, P<0.001; p38 at 3mo, F=41.662, P<0.001 and at 6mo, F=67.979, P<0.001). The retina claudin-1 and occludin levels in the model group were lower than that of the control group. They were also lower in treated group than that of the control group but were higher than that of the model group. The differences among three groups were statistically significant (claudin-1 at 3mo, F=139.088, P<0.001 and at 6mo, F=128.415, P<0.001; occludin at 3mo, F=92.733, P<0.001 and at 6mo, F=104.478, P<0.001). The retinal Evans blue leakage in the model group was higher than that of the control group. It was also higher in treated group than that of the control group but was lower than that of the model group. The differences among the three groups were statistically significant (at 3mo, F=447.946, P<0.001; at 6mo, F=1610.732, P<0.001).

CONCLUSION

In a diabetic rat model, infliximab may relieve TNF-α induced BRB breakdown via the B-Raf and p38 signaling pathway.

Corneal stromal stem cells reduce corneal scarring by mediating neutrophil infiltration after wounding

Corneal scarring limits vision for millions of individuals worldwide. Corneal transplantation (keratoplasty) is the standard of care for corneal opacity; however, it bears the risk of graft rejection and infection and is not universally available. Stem cell therapy holds promise as an alternative to keratoplasty. Stem cells from human corneal stroma (CSSC) induce regeneration of transparent corneal tissue in a mouse wound-healing model. In this study we investigated the mechanism by which CSSC prevent deposition of fibrotic tissue. Infiltration by CD11b+/Ly6G+ neutrophils and myeloperoxidase expression were increased in corneas 24 hr after corneal wounding but were reduced in CSSC-treated wounds. Secretion of TSG-6, a protein known to regulate neutrophil migration, was up-regulated in CSSC in response to TNFα and as CSSC differentiate to keratocytes. In vivo, wounded mouse corneas treated with CSSC contained human TSG-6. Inhibition of neutrophil infiltration into cornea by CSSC was reversed when TSG-6 expression was knocked down using siRNA. Silencing of TSG-6 expression in CSSC reduced their ability to block scarring and the expression of mRNA for fibrosis-associated proteins collagen III, tenascin C, and smooth muscle actin in wounded corneas. Neutropenic mice exhibited a significant reduction in corneal scarring and fibrotic mRNA expression 2 weeks after wounding. These results support the conclusion that neutrophil infiltration is an essential event in the fibrotic response to corneal damage and that prevention of scarring by CSSC is mediated by secretion of TSG-6 by these cells.

TSG-6 secreted by human umbilical cord-MSCs attenuates severe burn-induced excessive inflammation via inhibiting activations of P38 and JNK signaling

The hMSCs have become a promising approach for inflammation treatment in acute phase. Our previous study has demonstrated that human umbilical cord-MSCs could alleviate the inflammatory reaction of severely burned wound. In this study, we further investigated the potential role and mechanism of the MSCs on severe burn-induced excessive inflammation. Wistar rats were randomly divided into following groups: Sham, Burn, Burn+MSCs, Burn+MAPKs inhibitors, and Burn, Burn+MSCs, Burn+Vehicle, Burn+siTSG-6, Burn+rhTSG-6 in the both experiments. It was found that MSCs could only down-regulate P38 and JNK signaling, but had no effect on ERK in peritoneal macrophages of severe burn rats. Furthermore, suppression of P38 and JNK activations significantly reduced the excessive inflammation induced by severe burn. TSG-6 was secreted by MSCs using different inflammatory mediators. TSG-6 from MSCs and recombinant human (rh)TSG-6 all significantly reduced activations of P38 and JNK signaling induced by severe burn and then attenuated excessive inflammations. On the contrary, knockdown TSG-6 in the cells significantly increased phosphorylation of P38 and JNK signaling and reduced therapeutic effect of the MSCs on excessive inflammation. Taken together, this study suggested TSG-6 from MSCs attenuated severe burn-induced excessive inflammation via inhibiting activation of P38 and JNK signaling.

Tumor Necrosis Factor-stimulated Gene-6 (TSG-6) Is Constitutively Expressed in Adult Central Nervous System (CNS) and Associated with Astrocyte-mediated Glial Scar Formation following Spinal Cord Injury

Tumor necrosis factor (TNF)-stimulated gene-6 (TSG-6) binds to hyaluronan and can reorganize/stabilize its structure, also enhancing the binding of this glycosaminoglycan to its cell surface receptor, CD44. TSG-6 is rapidly up-regulated in response to inflammatory cytokines protecting tissues from the damaging effects of inflammation. Despite TSG-6 treatment having been shown to improve outcomes in an experimental model of traumatic brain injury, TSG-6 expression has not been extensively studied in the central nervous system (CNS). We hereby analyzed the expression profile of TSG-6 in the developing CNS and following injury. We show that TSG-6 is expressed in the rat CNS by GFAP(+) and CD44(+) astrocytes, solely in the mature brain and spinal cord, and is not present during the development of the CNS. TSG-6(-/-) mice present a reduced number of GFAP(+) astrocytes when compared with the littermate TSG-6(+/-) mice. TSG-6 expression is drastically up-regulated after injury, and the TSG-6 protein is present within the glial scar, potentially coordinating and stabilizing the formation of this hyaluronan-rich matrix. This study shows that TSG-6 is expressed in the CNS, suggesting a role for TSG-6 in astrocyte activation and tissue repair. We hypothesize that within this context TSG-6 could participate in the formation of the glial scar and confer anti-inflammatory properties. Further studies are required to elucidate the therapeutic potential of targeting TSG-6 after CNS injury to promote its protective effects while reducing the inhibitory properties of the glial scar in axon regeneration.