Molecular insights into complexation between protein and silica: Spectroscopic and simulation investigations.

The synergistic effect of protein-silica complexation leads to exacerbated membrane fouling in the membrane desalination process, exceeding the individual impacts of silica scaling or protein fouling. However, the molecular-level dynamics of silica binding to proteins and the resulting structural changes in both proteins and silica remain poorly understood. This study investigates the complexation process between silica and proteins-negatively charged bovine serum albumin (BSA) and positively charged lysozyme (LYZ) at neutral pH-using infrared spectroscopy (IR), in situ attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), and multiple computational simulations. The findings reveal that both protein and silica structures undergo changes during the complexation process, with calcium ions in the solution significantly exacerbating these alterations. In particular, in situ ATR-FTIR combined with two-dimensional correlation spectroscopy analysis shows that BSA experiences more pronounced unfolding, providing additional binding sites for silica adsorption compared to LYZ. The adsorbed proteins promote silica polymerization from lower-polymerized to higher-polymerized species. Furthermore, molecular dynamics simulations demonstrate greater conformational variation in BSA through root-mean-square-deviation analysis and the bridging role of calcium ions via mean square displacement analysis. Molecular docking and density functional theory calculations identify the binding sites and energy of silica on proteins. In summary, this research offers a comprehensive understanding of the protein-silica complexation process, contributing to the knowledge of synergistic behaviors of inorganic scaling and organic fouling on membrane surfaces. The integrated approach used here may also be applicable for exploring other complex complexation processes in various environments.

Liraglutide Attenuates Hepatic Ischemia-Reperfusion Injury by Modulating Macrophage Polarization.

Ischemia-reperfusion injury (IRI) is a common complication associated with liver surgery, and macrophages play an important role in hepatic IRI. Liraglutide, a glucagon-like peptide-1 (GLP-1) analog primarily used to treat type 2 diabetes and obesity, regulates intracellular calcium homeostasis and protects the cardiomyocytes from injury; however, its role in hepatic IRI is not yet fully understood. This study aimed to investigate whether liraglutide can protect the liver from IRI and determine the possible underlying mechanisms. Our results showed that liraglutide pretreatment significantly alleviated the liver damage caused by ischemia-reperfusion (I/R), as evidenced by H&E staining, serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels, and TUNEL staining. Furthermore, the levels of inflammatory cytokines elicited by I/R were distinctly suppressed by liraglutide pretreatment, accompanied by significant reduction in TNF-α, IL-1ß, and IL-6 levels. Furthermore, pretreatment with liraglutide markedly inhibited macrophage type I (M1) polarization during hepatic IRI, as revealed by the significant reduction in CD68+ levels in Kupffer cells (KCs) detected via flow cytometry. However, the protective effects of liraglutide on hepatic IRI were partly diminished in GLP-1 receptor-knockout (GLP-1R-/-) mice. Furthermore, in an in vitro study, we assessed the role of liraglutide in macrophage polarization by examining the expression profiles of M1 in bone marrow-derived macrophages (BMDMs) from GLP-1R-/- and C57BL/6J mice. Consistent with the results of the in vivo study, liraglutide treatment attenuated the LPS-induced M1 polarization and reduced the expression of M1 markers. However, the inhibitory effect of liraglutide on LPS-induced M1 polarization was largely abolished in BMDMs from GLP-1R-/- mice. Collectively, our study indicates that liraglutide can ameliorate hepatic IRI by inhibiting macrophage polarization towards an inflammatory phenotype via GLP-1R. Its protective effect against liver IRI suggests that liraglutide may serve as a potential drug for the clinical treatment of liver IRI.

Daidzein ameliorated concanavalin A-induced liver injury through the Akt/GSK-3ß/Nrf2 pathway in mice.

BACKGROUND: Daidzein is a soybean isoflavone that has been shown in previous studies to have anti-inflammatory and antioxidant effects. However, it remains unknown whether daidzein plays a protective role against concanavalin A (Con A)-induced autoimmune hepatitis (AIH). METHODS: In this study, an animal model of AIH was constructed by intravenous injection of Con A (15 mg/kg). Daidzein (200 mg/kg/d) was intraperitoneally administered to mice for 3 days before the Con A injection. Alpha mouse liver 12 (AML-12) cells were incubated in the absence or presence of daidzein to determine whether daidzein can alleviate Con A-induced hepatotoxicity. RESULTS: The findings showed that pretreatment with daidzein significantly reduced Con A-induced oxidative stress and hepatocyte apoptosis in Con A-induced liver injury. Pretreatment with daidzein significantly prevented the decrease of intrahepatic protein levels of phosphorylated Akt (p-Akt), phosphorylated GSK3ß (p-GSK3ß), nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and NOQ1 (NAD(P)H quinone dehydrogenase 1) in response to Con A administration. Meanwhile, malondialdehyde (MDA) production was reduced, and glutathione peroxidase (GPX), superoxide dismutase (SOD) activity, and SOD2 mRNA expression were elevated in daidzein-pretreated livers. In in vitro experiments, daidzein pretreatment prevented Con A-induced murine hepatocyte death. This effect was partly diminished by an inhibitor of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway. CONCLUSIONS: These results indicate that daidzein pretreatment attenuates Con A-induced liver injury through the Akt/GSK3ß/Nrf2 pathway. Our findings provide new insights into the use of plant-derived products for AIH treatment beyond immunosuppression.

Impairment of type H vessels by NOX2-mediated endothelial oxidative stress: critical mechanisms and therapeutic targets for bone fragility in streptozotocin-induced type 1 diabetic mice.

Rationale: Mechanisms underlying the compromised bone formation in type 1 diabetes mellitus (T1DM), which causes bone fragility and frequent fractures, remain poorly understood. Recent advances in organ-specific vascular endothelial cells (ECs) identify type H blood vessel injury in the bone, which actively direct osteogenesis, as a possible player. Methods: T1DM was induced in mice by streptozotocin (STZ) injection in two severity degrees. Bony endothelium, the coupling of angiogenesis and osteogenesis, and bone mass quality were evaluated. Insulin, antioxidants, and NADPH oxidase (NOX) inhibitors were administered to diabetic animals to investigate possible mechanisms and design therapeutic strategies. Results: T1DM in mice led to the holistic abnormality of the vascular system in the bone, especially type H vessels, resulting in the uncoupling of angiogenesis and osteogenesis and inhibition of bone formation. The severity of osteopathy was positively related to glycemic levels. These pathological changes were attenuated by early-started, but not late-started, insulin therapy. ECs in diabetic bones showed significantly higher levels of reactive oxygen species (ROS) and NOX 1 and 2. Impairments of bone vessels and bone mass were effectively ameliorated by treatment with anti-oxidants or NOX2 inhibitors, but not by a NOX1/4 inhibitor. GSK2795039 (GSK), a NOX2 inhibitor, significantly supplemented the insulin effect on the diabetic bone. Conclusions: Diabetic osteopathy could be a chronic microvascular complication of T1DM. The impairment of type H vessels by NOX2-mediated endothelial oxidative stress might be an important contributor that can serve as a therapeutic target for T1DM-induced osteopathy.

Suppression of histone deacetylases by SAHA relieves bone cancer pain in rats via inhibiting activation of glial cells in spinal dorsal horn and dorsal root ganglia.

BACKGROUND: Robust activation of glial cells has been reported to occur particularly during the pathogenesis of bone cancer pain (BCP). Researchers from our group and others have shown that histone deacetylases (HDACs) play a significant role in modulating glia-mediated immune responses; however, it still remains unclear whether HDACs are involved in the activation of glial cells during the development of BCP. METHODS: BCP model was established by intra-tibia tumor cell inoculation (TCI). The expression levels and distribution sites of histone deacetylases (HDACs) in the spinal dorsal horn and dorsal root ganglia were evaluated by Western blot and immunofluorescent staining, respectively. Suberoylanilide hydroxamic acid (SAHA), a clinically used HDAC inhibitor, was then intraperitoneally and intrathecally injected to rescue the increased expression levels of HDAC1 and HDAC2. The analgesic effects of SAHA administration on BCP were then evaluated by measuring the paw withdrawal thresholds (PWTs). The effects of SAHA on activation of glial cells and expression of proinflammatory cytokines (TNF-α, IL-1ß, and IL-6) in the spinal dorsal horn and dorsal root ganglia of TCI rats were further evaluated by immunofluorescent staining and Western blot analysis. Subsequently, the effects of SAHA administration on tumor growth and cancer cell-induced bone destruction were analyzed by hematoxylin and eosin (HE) staining and micro-CT scanning. RESULTS: TCI caused rapid and long-lasting increased expression of HDAC1/HDAC2 in glial cells of the spinal dorsal horn and dorsal root ganglia. Inhibiting HDACs by SAHA not only reversed TCI-induced upregulation of HDACs but also inhibited the activation of glial cells in the spinal dorsal horn and dorsal root ganglia, and relieved TCI-induced mechanical allodynia. Further, we found that SAHA administration could not prevent cancer infiltration or bone destruction in the tibia, which indicated that the analgesic effects of SAHA were not due to its anti-tumor effects. Moreover, we found that SAHA administration could inhibit GSK3ß activity in the spinal dorsal horn and dorsal root ganglia, which might contributed to the relief of BCP. CONCLUSION: Our findings suggest that HDAC1 and HDAC2 are involved in the glia-mediated neuroinflammation in the spinal dorsal horn and dorsal root ganglia underlying the pathogenesis of BCP, which indicated that inhibiting HDACs by SAHA might be a potential strategy for pain relief of BCP.

Protective effect of the glucagon-like peptide-1 analogue liraglutide on carbon tetrachloride-induced acute liver injury in mice.

Acute liver injury seriously endangers human health. Liraglutide, a glucagon-like peptide-1 (GLP-1) analogue, has antioxidative effects in addition to being widely used in the treatment of type 2 diabetes and was reported to ameliorate liver diseases. The aim of this study was to evaluate the hepatoprotective effects of liraglutide on carbon tetrachloride (CCl4)-induced acute liver injury in mice and to investigate the mechanisms involved in this protective effect. Male BALB/c mice were pre-treated with liraglutide (200 µg/kg/day) by hypodermic injection for 3 days before a 0.1% (v/v) CCl4 (10 ml/kg, dissolved in olive oil) intraperitoneal injection, or post-treated with liraglutide once immediately after a CCl4 intraperitoneal injection. The experimental data showed that liraglutide treatment significantly decreased the serum ALT and AST levels and ameliorated the liver histopathological changes induced by CCl4. In addition, liraglutide pre-treatment dramatically increased the number of proliferating cell nuclear antigen (PCNA)-positive hepatocytes and significantly reduced hepatocyte apoptosis after CCl4 treatment. As a consequence, liraglutide pre-treatment significantly prevented CCl4-induced malondialdehyde (MDA) production and increased the activity of the antioxidant superoxide dismutase (SOD) enzyme. In addition, liraglutide pre-treatment significantly ameliorated mitochondrial respiratory functions and ultrastructural features. Furthermore, liraglutide pre-treatment enhances the activation of the NRF2/HO-1 signaling pathway. In summary, liraglutide protects against CCl4-induced acute liver injury by protecting mitochondrial functions and inhibiting oxidative stress, which may partly involve the activation of NRF2/HO-1 signaling pathway.

XPro1595 ameliorates bone cancer pain in rats via inhibiting p38-mediated glial cell activation and neuroinflammation in the spinal dorsal horn.

Bone cancer pain (BCP) profoundly compromises the life quality of patients with bone metastases. Severe side effects of the drugs which were widely used and effective in the various stages of this condition results in a huge challenge for BCP treatment. Here, we investigated the antinociceptive effects of XPro1595, a soluble tumor necrosis factor (solTNF) inhibitor with considerable immunoregulatory efficacy, on BCP, as well as the underlying mechanisms within the spinal dorsal horn (SDH). Walker 256 mammary gland carcinoma cells were intratibially inoculated to induce BCP. Intrathecal administration of XPro1595 alleviated bone cancer-induced chronic pain in a dose-dependent manner, with an ED50 of 9.69 mg/kg. Bone cancer resulted in the activation of astrocytes and microglia in the SDH through the upregulation of mitogen-activated protein kinase (MAPK) pathways, which was accompanied by an over-expression of pro-inflammatory cytokines, including TNF-α, IL-1ß, and IL-6. XPro1595suppressed bone cancer-evoked glial activation and the consequent neuroinflammation. These inhibitory effects of XPro1595 were, at least partially, mediated by a reduction in the phosphorylation of p38 MAPK in spinal glial cells. In conclusion, inhibition of spinal glia by XPro1595 may have utility in the treatment of bone cancer-induced neuroinflammation, and our results further implicate XPro1595 as a new promising therapeutic agent for BCP.

Fecal microbiota transplantation alleviates myocardial damage in myocarditis by restoring the microbiota composition.

Myocarditis can be caused by several infectious and noninfectious causes. Treatment for myocarditis is still a difficult task in clinical practice. The gut microbiota is related to cardiovascular diseases such as atherosclerosis and hypertension. However, little is known about the role of the gut microbiota in myocarditis. In our study, we tested the hypothesis that gut dysbiosis is associated with myocarditis. We focused on whether fecal microbiota transplantation (FMT) can be used as an effective treatment for myocarditis. We used an experimental autoimmune myocarditis (EAM) mouse model. Fecal samples were isolated from the control and EAM groups for bacterial genome analysis. We observed an increase in microbial richness and diversity in the myocarditis mice. These changes were accompanied by an increased Firmicutes/Bacteroidetes ratio. We also evaluated the efficacy of FMT for the treatment of myocarditis. EAM mouse guts were repopulated with fecal contents from an untreated male mouse donor. We found that myocardial injury was improved by diminished inflammatory infiltration, showing that IFN-γ gene expression in the heart tissue and CD4+IFN-γ+ cells in the spleen were decreased after FMT in EAM mice. We also found that FMT was able to rebalance the gut microbiota by restoring the Bacteroidetes population and reshaping the microbiota composition. Myocarditis is associated with gut microbiota dysbiosis and characterized by an increased F/B ratio. FMT treatment can rebalance the gut microbiota and attenuate myocarditis. Thus, FMT may be a potential therapeutic strategy for the treatment of myocarditis.

The conditioned medium of human mesenchymal stromal cells reduces irradiation-induced damage in cardiac fibroblast cells.

Recently, multipotent mesenchymal stromal cell (MSC) treatment has attracted special attention as a new alternative strategy for stimulating regeneration. Irradiation myocardial fibrosis (IMF) is a major complication associated with total body irradiation for hematopoietic stem cell transplantation, nuclear accidents, and thoracic radiotherapy for lung cancer, esophageal cancer, proximal gastric cancer, breast cancer, thymoma, and lymphoma. The aim of the present study was to assess the therapeutic paracrine effects of human umbilical cord-derived mesenchymal stromal cells (UC-MSCs) in the cell model of IMF. For this purpose, primary human cardiac fibroblasts (HCF) cells were irradiated and cultured with the conditioned medium of UC-MSCs (MSCCM). MSCCM promoted cell viability, reduced collagen deposition as measured by Sircol assay and qPCR (Col1A1 and Col1A2), prevented oxidative stress and increased antioxidant status (as measured by malondialdehyde content and the activities and mRNA levels of antioxidant enzymes), and reduced pro-fibrotic TGF-ß1, IL-6 and IL-8 levels (as examined by ELISA kit and qPCR). Pretreatment with inhibitor of NF-κB led to a decrease in the levels of TGF-ß1 in cell lysate of HCF cells by ELISA kit. Furthermore, we also found that MSCCM prevented NF-κB signaling pathway activation for its proinflammatory actions induced by irradiation. Taken together, our data suggest that MSCCM could reduce irradiation-induced TGF-ß1 production through inhibition of the NF-κB signaling pathway. These data provide new insights into the functional actions of MSCCM on irradiation myocardial fibrosis.

Angiogenesis impairment by the NADPH oxidase-triggered oxidative stress at the bone-implant interface: Critical mechanisms and therapeutic targets for implant failure under hyperglycemic conditions in diabetes.

Mechanism underlying the diabetes-induced poor osteointegration of implants remains elusive, making it a challenge to develop corresponding solutions. Here, we studied the role of angiogenesis in the diabetes-induced poor bone repair at the bone-implant interface (BII) and the related mechanisms. In vivo, titanium screws were implanted in the femurs of mice, and, in vitro, vascular endothelial cell (VEC) was cultured on titanium surface. Results showed that, compared with normal milieu (NM), diabetic milieu (DM) led to angiogenesis inhibition around implants which resulted in reduced osteoprogenitors and poor bone formation on BII in vivo. In vitro, DM caused significant increase of NADPH oxidases (NOX), dysfunction of mitochondria and overproduction of reactive oxygen species (ROS) in VEC on titanium surface, inducing obvious cell dysfunction. Both Mito-TEMPO (Mito, a mitochondria-targeted ROS antagonist) and apocynin (APO, a NOX inhibitor) effectively attenuated the oxidative stress and dysfunction of VEC, with the beneficial effects of APO significantly better than those of Mito. Further study showed that the diabetes-induced metabolic disturbance of VEC was significantly related to the increase of advanced glycation end products (AGEs) at the BII. Our results suggested that the AGEs-related and NOX-triggered cellular oxidative stress leads to VEC dysfunction and angiogenesis impairment at the BII, which plays a critical role in the compromised implant osteointegration under diabetic conditions. These demonstrated new insights into the BII in pathological states and also provided NOX and AGEs as promising therapeutic targets for developing novel implant materials to accelerate the angiogenesis and osteointegration of implants in diabetic patients with hyperglycemia. STATEMENT OF SIGNIFICANCE: The high failure rate of bone implants in diabetic patients causes patients terrible pain and limits the clinical application of implant materials. The mechanism underlying this phenomenon needs elucidation so that it would be possible to develop corresponding solutions. Our study demonstrated that the AGEs-related and NOX-triggered oxidative stress of VEC leads to angiogenesis impairment at the bone-implant interface (BII) in diabetes. These are critical mechanisms underlying the compromised implant osteointegration in diabetic hyperglycemia. These provide new insights into the BII in diseased states and also suggest NOX and AGEs as crucial therapeutic targets for developing novel implant materials which could modulate the oxidative stress on BII to get improved osteointegration and reduced implant failure, especially in diabetic patients.

The glucagon-like peptide-1 (GLP-1) analog liraglutide attenuates renal fibrosis.

Renal fibrosis is recognized as the common route of all chronic kidney disease (CKD) progressing to end-stage renal disease (ESRD). Additionally, accumulating evidence suggests that epithelial-mesenchymal transition (EMT) plays a significant role in the process of renal fibrogenesis. Liraglutide is a long-acting glucagon-like peptide-1 (GLP-1) analog that has been widely used to treat type 2 diabetes. Recent studies have demonstrated that the GLP-1 analogs could also exert protective effects in cardiac fibrosis models. However, the effects of liraglutide on the progression of CKD remain largely unknown. In the present study, we investigated the effects of liraglutide on the progression to renal fibrosis induced by unilateral ureteral obstruction (UUO) and EMT of rat renal tubular epithelial cells (NRK-52E) induced with recombinant transforming growth factor-beta 1 (TGF-ß1). The results indicated that UUO increased collagen deposition and the mRNA expression of fibronectin (FN) and collagen type I alpha 1 (Col1α1) in the obstructed kidney tissues. The effects were blunted in liraglutide-treated UUO mice compared with control mice. The upregulation of Snail1 and alpha smooth muscle actin (α-SMA), and downregulation of E-cadherin revealed that EMT occurred in the UUO kidneys, and these effects were ameliorated following liraglutide treatment. Additionally, liraglutide treatment decreased the expression of TGF-ß1 and its receptor (TGF-ß1R) and inhibited the activation of its downstream signaling molecules (pSmad3 and pERK1/2). The in vitro results showed that the EMT and extracellular matrix (ECM) secretion of NRK-52E cells were induced by TGF-ß1. In addition, the Smad3 and ERK1/2 signaling pathways were highly activated in cells cultured with TGF-ß1. All these effects were attenuated by liraglutide treatment. However, the protective effects of liraglutide were abolished by co-incubation of the GLP-1 receptor (GLP-1R) antagonist exendin-3 (9-39). These results suggest that liraglutide attenuates the EMT and ECM secretion of NRK-52E cells induced by TGF-ß1 and EMT and renal fibrosis induced by UUO. The potential mechanism involves liraglutide binding to and activating GLP-1R, which prevents EMT by inhibiting the activation of TGF-ß1/Smad3 and ERK1/2 signaling pathways, thereby decreasing the ECM secretion and deposition. Therefore, liraglutide is a promising therapeutic agent that may halt the progression of renal fibrosis.

Lactic acid of PLGA coating promotes angiogenesis on the interface between porous titanium and diabetic bone.

The diabetes-related high failure risk for endosseous implants needs efficacious methods to improve osteointegration on the bone-implant interface (BII). Poly(lactic-co-glycolic) acid (PLGA) is widely used in tissue engineering but its effects on the BII in diabetes remain unclear. To clarify this issue, 3D-printed porous titanium implants (TI) with and without PLGA coating were fixed in the bone defects of sheep in vivo, and vascular endothelial cells (VEC) and osteoblasts were incubated on the implant surface under normal conditions (NC) and diabetic conditions (DC) in vitro. The results showed that the PLGA coating promoted angiogenesis on the BII and the osteointegration of TI in diabetic sheep. The PLGA coating attenuated the DC-induced dysfunctions of VEC but not of osteoblasts. When VEC and osteoblasts were co-cultured in DC, the PLGA coating showed protective effects on the osteoblasts. Lactic acid (LA) but not glycolic acid (GA), both of which are degradation products of PLGA, induced similar effects to those of PLGA. These results suggest that PLGA coating on TI could promote angiogenesis in diabetes by its degradation production of LA, thus indirectly improving the bone formation on BII. Furthermore, PLGA exerted its effects, at least partially, through inhibiting the pathological effects of advanced glycation end products (AGEs) on the BII. This is the first study of the effects of PLGA on angiogenesis on the BII and the first findings on the inhibitory effects of PLGA on AGEs. Our findings demonstrate that PLGA is a promising interface-modification component for fabricating implants with better angiogenesis and osteointegration on the BII under diabetic conditions. This strategy might be applicable for reducing implant failure in diabetic patients.

The analgesic effects of triptolide in the bone cancer pain rats via inhibiting the upregulation of HDACs in spinal glial cells.

BACKGROUND: Bone cancer pain (BCP) severely compromises the quality of life, while current treatments are still unsatisfactory. Here, we tested the antinociceptive effects of triptolide (T10), a substance with considerable anti-tumor efficacies on BCP, and investigated the underlying mechanisms targeting the spinal dorsal horn (SDH). METHODS: Intratibial inoculation of Walker 256 mammary gland carcinoma cells was used to establish a BCP model in rats. T10 was intrathecally injected, and mechanical allodynia was tested by measuring the paw withdrawal thresholds (PWTs). In mechanism study, the activation of microglia, astrocytes, and the mitogen-activated protein kinase (MAPK) pathways in the SDH were evaluated by immunofluorescence staining or Western blot analysis of Iba-1, GFAP, p-ERK, p-p38, and p-JNK. The expression and cellular localization of histone deacetylases (HDACs) 1 and 2 were also detected to investigate molecular mechanism. RESULTS: Intrathecal injection of T10 inhibited the bone cancer-induced mechanical allodynia with an ED50 of 5.874 µg/kg. This effect was still observed 6 days after drug withdrawal. Bone cancer caused significantly increased expression of HDAC1 in spinal microglia and neurons, with HDAC2 markedly increased in spinal astrocytes, which were accompanied by the upregulation of MAPK pathways and the activation of microglia and astrocytes in the SDH. T10 reversed the increase of HDACs, especially those in glial cells, and inhibited the glial activation. CONCLUSIONS: Our results suggest that the upregulation of HDACs contributes to the pathological activation of spinal glial cells and the chronic pain caused by bone cancer, while T10 help to relieve BCP possibly via inhibiting the upregulation of HDACs in the glial cells in the SDH and then blocking the neuroinflammation induced by glial activation.

Adiponectin improves the osteointegration of titanium implant under diabetic conditions by reversing mitochondrial dysfunction via the AMPK pathway in vivo and in vitro.

Diabetes-induced reactive oxygen species (ROS) overproduction would result in compromised osteointegration of titanium implant (TI) and high rate of implant failure, yet the underlying mechanisms remain elusive. Adiponectin (APN) is a fat-derived adipocytokine with strong antioxidant, mitochondrial-protective and anti-diabetic efficacies. We hypothesized that mitochondrial dysfunction under diabetes may account for the oxidative stress in osteoblasts and titanium-bone interface (TBI) instability, which could be ameliorated by APN. To test this hypothesis, we incubated primary rat osteoblasts on TI and tested the cellular behaviors when subjected to normal milieu (NM), diabetic milieu (DM), DM+APN, DM+AICAR (AMPK activator) and DM+APN+Compound C (AMPK inhibitor). In vivo, APN or APN+Compound C were administered to diabetic db/db mice with TI implanted in their femurs. Results showed that diabetes induced structural damage, dysfunction and content decrease of mitochondria in osteoblasts, which led to ROS overproduction, dysfunction and apoptosis of osteoblasts accompanied by the inhibition of AMPK signaling. APN alleviated the mitochondrial damage by activating AMPK, thus reversing osteoblast impairment and improving the osteointegration of TI evidenced by Micro-CT and histological analysis. Furthermore, AICAR showed beneficial effects similar to APN treatment, while the protective effects of APN were abolished when AMPK activation was blocked by Compound C. This study clarifies mitochondrial dysfunction as a crucial mechanism in the impaired bone healing and implant loosening in diabetes, and provides APN as a novel promising active component for biomaterial-engineering to improve clinical performance of TI in diabetic patients. STATEMENT OF SIGNIFICANCE: The loosening rate of titanium implants in diabetic patients is high. The underlying mechanisms remain elusive and, with the rapid increase of diabetic morbility, efficacious strategies to mitigate this problem have become increasingly important. Our study showed that the mitochondrial impairment and the consequent oxidative stress in osteoblasts at the titanium-bone interface (TBI) play a critical role in the diabetes-induced poor bone repair and implant destabilization, which could become therapeutic targets. Furthermore, adiponectin, a cytokine, promotes the bio-functional recovery of osteoblasts and bone regeneration at the TBI in diabetes. This provides APN as a novel bioactive component used in material-engineering to promote the osteointegration of implants, which could reduce implant failure, especially for diabetic patients.

Beneficial effect of corticosteroids for patients with severe drug-induced liver injury.

OBJECTIVE: The efficacy of corticosteroids in drug-induced liver injury (DILI) remains controversial. We aimed to determine whether corticosteroids were beneficial for severe DILI. METHODS: This was a single-center retrospective study of patients with DILI enrolled between January 2010 and May 2015. RESULTS: Of the 203 patients enrolled, 53 were treated with corticosteroids. The baseline characteristics of patients received corticosteroids were more severe than that of the non-corticosteroid group. Subgroup analyses indicated that almost all patients who died had the higher 50% quartile of total bilirubin (TB) levels. Among the 50-75% quartile of TB level, no patient in the corticosteroids group but 3 (15.0%) of 20 patients in the non-corticosteroid group died (P = 0.261). With the highest 25% quartile of TB level, four patients in the corticosteroids group and four in the non-corticosteroids group died (P = 0.405). Corticosteroid therapy improved the recovery rate from 77.4% to 87.9% in the higher 50% quartile of TB values (P = 0.331). More interestingly, corticosteroid administration hastened the resolution of liver injury by shortening the duration of peak TB to 50% reduction from 17 to 12 days (P < 0.05). Additionally, multivariate analysis revealed that the TB levels and cholestatic injury type were the two independent factors associated with a poor outcome of DILI. CONCLUSIONS: Corticosteroids are not detrimental to DILI, but instead ameliorate liver injury and improve patient survival. Short-time use of corticosteroids is strongly recommended for severe DILI patients with hyperbilirubinemia.

Activated Circulating Myeloid-Derived Suppressor Cells in Patients with Dilated Cardiomyopathy.

BACKGROUND/AIMS: Myeloid-derived suppressor cells (MDSCs) are increased in inflammatory and autoimmune disorders. This study aims to evaluate the significance of MDSCs in dilated cardiomyopathy (DCM) patients. METHODS: In total, 42 newly hospitalized DCM patients and 39 healthy controls were enrolled in the study. The frequencies of circulating CD14+HLA-DR-/low MDSCs were determined by flow cytometry. Then, the functional properties of MDSCs in suppressing T cell proliferation and interferon-gamma (IFN-x03B3;) production were measured in a co-culture model. Then, mRNA expression levels of various important molecules in peripheral blood mononuclear cells were measured by real time polymerase chain reaction. Furthermore, correlation analyses between MDSC frequencies and cardiac function parameters were also performed. RESULTS: The frequencies of circulating CD14+HLA-DR-/low MDSCs were significantly elevated in DCM patients compared with healthy controls. It showed that MDSCs from DCM patients more effectively suppressed T cell proliferation and IFN-x03B3; production compared with those from healthy controls, which was partially mediated by arginase-1 (Arg-1). In addition, the correlation analysis suggested that MDSC frequencies were negatively correlated with left ventricular ejection fraction (LVEF), while positively with N-terminal pro-brain natriuretic peptide (NT-proBNP) in patients with DCM. CONCLUSIONS: Circulating activated MDSCs might play significant immunomodulatory roles in the pathogenesis of DCM.

Human umbilical vein endothelial cells promote the inhibitory activation of CD4(+)CD25(+)Foxp3(+) regulatory T cells via PD-L1.

BACKGROUND: Atherosclerosis (AS) is a chronic inflammation characterized by massive infiltration of inflammatory cells in arterial wall plaques. Programmed death ligand-1 (PD-L1), a co-stimulatory molecule, plays a vital role in regulating immune responses. We investigated the role and mechanisms of PD-L1 expressed on oxidized low-density lipoprotein (ox-LDL)-impaired human umbilical vein endothelial cells (HUVECs) in promoting activation and cytokine production of CD4(+)CD25(+) forkhead box P3 (FoxP3) regulatory T cells (Tregs). METHODS AND RESULTS: Tregs were incubated alone, with HUVECs or HUVECs pre-stimulated with ox-LDL in the presence of anti-CD3 monoclonal antibodies (mAbs) for 48 h. HUVECs were shown to upregulate the immune phenotypic markers of Tregs, such as glucocorticoid-induced TNF receptor (GITR), cytotoxic T lymphocyte antigen-4 (CTLA-4) and programmed cell death-1 protein (PD-1). Moreover, HUVECs modulated cytokine production of Tregs (e.g., interleukin-10 (IL-10) and transforming growth factor-ß1 (TGF-ß1)). HUVECs treated with anti-PD-L1 mAbs were unable to regulate the surface expression and cytokine production of Tregs. The Transwell culture system suggested that interaction between HUVECs and Tregs via PD-L1 requires cell-to-cell contact. CONCLUSION: Expression of the negative co-stimulatory molecule PD-L1 on HUVECs may upregulate the inhibitory activation and cytokine production of CD4(+)CD25(+)Foxp3(+) regulatory T cells in AS.

Expansion of myeloid-derived suppressor cells in patients with acute coronary syndrome.

AIM: The aim of this study was to explore whether the circulating frequency and function of myeloid-derived suppressor cells (MDSCs) are altered in patients with acute coronary syndrome (ACS). METHODS: The frequency of MDSCs in peripheral blood was determined by flow cytometry, and mRNA expression in purified MDSCs was analyzed by real-time reverse transcription polymerase chain reaction (RT-PCR). The suppressive function of MDSCs isolated from different groups was also determined. The plasma levels of certain cytokines were determined using Bio-Plex Pro™ Human Cytokine Assays. RESULTS: The frequency of circulating CD14(+)HLA-DR(-/low) MDSCs; arginase-1 (Arg-1) expression; and plasma levels of interleukin (IL)-1ß, IL-6, tumor necrosis factor (TNF)-α, and IL-33 were markedly increased in ACS patients compared to stable angina (SA) or control patients. Furthermore, MDSCs from ACS patients were more potent suppressors of T-cell proliferation and IFN-γ production than those from the SA or control groups at ratios of 1:4 and 1:2; this effect was partially mediated by Arg-1. In addition, the frequency of MDSCs was positively correlated with plasma levels of IL-6, IL-33, and TNF-α. CONCLUSIONS: We observed an increased frequency and suppressive function of MDSCs in ACS patients, a result that may provide insights into the mechanisms involved in ACS.