Jingjing Gan

An orally administrated nucleotide-delivery vehicle targeting colonic macrophages for the treatment of inflammatory bowel disease.

Tumor necrosis factor-alpha (TNF-α) plays a central role in the pathogenesis of inflammatory bowel disease (IBD). Anti-TNF-α therapies have shown protective effects against colitis, but an efficient tool for target suppression of its secretion - ideally via oral administration - remains in urgent demand. In the colon tissue, TNF-α is mainly secreted by the colonic macrophages. Here, we report an orally-administrated microspheric vehicle that can target the colonic macrophages and suppress the local expression of TNF-α for IBD treatment. This vehicle is formed by cationic konjac glucomannan (cKGM), phytagel and an antisense oligonucleotide against TNF-α. It was given to dextran sodium sulfate (DSS) colitic mice via gastric perfusion. The unique swelling properties of cKGM enabled the spontaneous release of cKGM& antisense nucleotide (ASO) nano-complex from the phytagel scaffold into the colon lumen, where the ASO was transferred into colonic macrophages via receptor-mediated phagocytosis. The treatment significantly decreased the local level of TNF-α and alleviated the symptoms of colitis in the mice. In summary, our study demonstrates a convenient, orally-administrated drug delivery system that effectively targets colonic macrophages for suppression of TNF-α expression. It may represent a promising therapeutic approach in the treatment of IBD.

Specifically Formed Corona on Silica Nanoparticles Enhances Transforming Growth Factor β1 Activity in Triggering Lung Fibrosis

A corona is a layer of macromolecules formed on a nanoparticle surface in vivo. It can substantially change the biological identity of nanomaterials and possibly trigger adverse responses from the body tissues. Dissecting the role of the corona in the development of a particular disease may provide profound insights for understanding toxicity of nanomaterials in general. In our present study, we explored the capability of different silica nanoparticles (SiNPs) to induce silicosis in the mouse lung and analyzed the composition of coronas formed on these particles. We found that SiNPs of certain size and surface chemistry could specifically recruit transforming growth factor β1 (TGF-β1) into their corona, which subsequently induces the development of lung fibrosis. Once embedded into the corona on SiNPs, TGF-β1 was remarkably more stable than in its free form, and its fibrosis-triggering activity was significantly prolonged. Our study meaningfully demonstrates that a specific corona component on a certain nanoparticle could initiate a particular pathogenic process in a clinically relevant disease model. Our findings may shed light on the understanding of molecular mechanisms of human health risks correlated with exposure to small-scale substances.

Autophagy mediated CoCrMo particle-induced peri-implant osteolysis by promoting osteoblast apoptosis

Wear particle-induced osteolysis is the leading cause of aseptic loosening, which is the most common reason for THA (total hip arthroplasty) failure and revision surgery. Although existing studies suggest that osteoblast apoptosis induced by wear debris is involved in aseptic loosening, the underlying mechanism linking wear particles to osteoblast apoptosis remains almost totally unknown. In the present study, we investigated the effect of autophagy on osteoblast apoptosis induced by CoCrMo metal particles (CoPs) in vitro and in a calvarial resorption animal model. Our study demonstrated that CoPs stimulated autophagy in osteoblasts and PIO (particle-induced osteolysis) animal models. Both autophagy inhibitor 3-MA (3-methyladenine) and siRNA of Atg5 could dramatically reduce CoPs-induced apoptosis in osteoblasts. Further, inhibition of autophagy with 3-MA ameliorated the severity of osteolysis in PIO animal models. Moreover, 3-MA also prevented osteoblast apoptosis in an antiautophagic way when tested in PIO model. Collectively, these results suggest that autophagy plays a key role in CoPs-induced osteolysis and that targeting autophagy-related pathways may represent a potential therapeutic approach for treating particle-induced peri-implant osteolysis.

Targeted delivery of let-7b to reprogramme tumor-associated macrophages and tumor infiltrating dendritic cells for tumor rejection.

Both tumor associated macrophages (TAMs) and tumor infiltrating dendritic cells (TIDCs) are important components in the tumor microenvironment that mediate tumor immunosuppression and promote cancer progression. Targeting these cells and altering their phenotypes may become a new strategy to recover their anti-tumor activities and thereby restore the local immune surveillance against tumor. In this study, we constructed a nucleic acid delivery system for the delivery of let-7b, a synthetic microRNA mimic. Our carrier has an affinity for the mannose receptors on TAMs/TIDCs and is responsive to the low-pH tumor microenvironment. The delivery of let-7b could reactivate TAMs/TIDCs by acting as a TLR-7 agonist and suppressing IL-10 production in vitro. In a breast cancer mouse model, let-7b delivered by this system efficiently reprogrammed the functions of TAMs/TIDCs, reversed the suppressive tumor microenvironment, and inhibited tumor growth. Taken together, this strategy, designed based upon TAMs/TIDCs-targeting delivery and the dual biological functions of let-7b (TLR-7 ligand and IL-10 inhibitor), may provide a new approach for cancer immunotherapy.

Dual TNF-α/IL-12p40 Interference as a Strategy to Protect Against Colitis Based on miR-16 Precursors With Macrophage Targeting Vectors

Cytokines are central components of the mucosal inflammatory responses that take place during the development of Crohns disease. Cell-specific combination therapies against cytokines may lead to increased efficacy and even reduced side effects. Therefore, a colonic macrophage-specific therapy using miR-16 precursors that can target both TNF-α and IL-12p40 was tested for its efficacy in experimental colitic mice. Galactosylated low molecular weight chitosan (G-LMWC) associated with miR-16 precursors were intracolonically injected into mice. The cellular localization of miR-16 precursors was determined. The therapeutic effects and possible mechanism were further studied in 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitic mice. The results show that specific upregulation of miR-16 level in colonic macrophages significantly reduces TNF-α and IL-12p40 expression, which could suppress the associated mucosal inflammation and ultimately result in the relief of colitic symptoms. This strategy, based on the dual silencing of colonic macrophage-specific cytokines, represents a potential therapeutic approach that may be valuable for colitis therapy.

ER Stress Mediates TiAl6V4 Particle-Induced Peri-Implant Osteolysis by Promoting RANKL Expression in Fibroblasts.

Wear particle-induced osteolysis is a major cause of aseptic loosening, which is one of the most common reasons for total hip arthroplasty (THA) failure. Previous studies have shown that the synovial fibroblasts present in the periprosthetic membrane are important targets of wear debris during osteolysis. However, the interaction mechanisms between the wear debris and fibroblasts remain largely unknown. In the present study, we investigated the effect of ER (endoplasmic reticulum) stress induced by TiAl6V4 particles (TiPs) in human synovial fibroblasts and calvarial resorption animal models. The expression of ER stress markers, including IRE1-α, GRP78/Bip and CHOP, were determined by western blot in fibroblasts that had been treated with TiPs for various times and concentration. To address whether ER stress was involved in the expression of RANKL, the effects of ER stress blockers (including 4-PBA and TUDCA) on the expression of RANKL in TiPs-treated fibroblasts were examined by real-time PCR, western blot and ELISA. Osteoclastogenesis was assessed by tartrate resistant acid phosphatase (TRAP) staining. Our study demonstrated that ER stress markers were markedly upregulated in TiPs-treated fibroblasts. Blocking ER stress significantly reduced the TiPs-induced expression of RANKL both in vitro and in vivo. Moreover, the inhibition of ER stress ameliorated wear particle-induced osteolysis in animal models. Taken together, these results suggested that the expression of RANKL induced by TiPs was mediated by ER stress in fibroblasts. Therefore, down regulating the ER stress of fibroblasts represents a potential therapeutic approach for wear particle-induced periprosthetic osteolysis.

Probiotics protect mice from CoCrMo particles-induced osteolysis

Wear particle-induced inflammatory osteolysis is the primary cause of aseptic loosening, which is the most common reason for total hip arthroplasty (THA) failure in the med- and long term. Recent studies have suggested an important role of gut microbiota (GM) in modulating the host metabolism and immune system, leading to alterations in bone mass. Probiotic bacteria administered in adequate amounts can alter the composition of GM and confer health benefits to the host. Given the inflammatory osteolysis that occurs in wear debris-induced prosthesis loosening, we examined whether the probiotic Lactobacillus casei could reduce osteolysis in a mouse calvarial resorption model. In this study, L. casei markedly protected mice from CoCrMo particles (CoPs)-induced osteolysis. Osteoclast gene markers and the number of osteoclasts were significantly decreased in L. casei-treated mice. Probiotic treatment decreased the M1-like macrophage phenotype indicated by downregulation of tumor necrosis factor α (TNF-α), interleukin (IL)-6 and inducible nitric oxide synthase (iNOS) and increased the M2-like macrophage phenotype indicated by upregulation of IL-4, IL-10 and arginase. Collectively, these results indicated that the L. casei treatment modulated the immune status and suppressed wear particle-induced osteolysis in vivo. Thus, probiotic treatment may represent a potential preventive and therapeutic approach to reduced wear debris-induced osteolysis.

APTES-modified nanosilica -- but neither APTES nor nanosilica -- inhibits endothelial cell growth via arrest of cell cycle at G1 phase:

The adverse effects of nanomaterials on the living system have attracted considerable attention in the past few years. Such effects may come from either the core nanomaterials or the chemical agents used to modify the nanomaterials – the latter being largely overlooked. In a free form, these modifying agents might have little impact on living cells; however, they may exhibit distinct biological effects when they assemble into a larger dimension. Here, we report that (3-aminopropyl)triethoxysilane – a small molecule compound ubiquitously employed to functionalise nanosilica surface – could decrease the viability of human umbilical vein endothelial cells when it was grafted onto the nanosilica surface. However, intriguingly, such effect was not found in 3-aminopropyl)triethoxysilane itself, the unmodified silica nanoparticles or the 3-aminopropyl)triethoxysilane-modified microparticles. Change of surface charge was excluded as a cause and apoptosis was not observed. Nevertheless, the 3-aminopropyl)triethoxysilane-modified nanoparticles could exclusively arrest cell cycle at G1 phase. Our findings suggest that substances could gain ‘new’ functions at the nanoscale, which may not be found in their larger or smaller counterparts. Understanding of such effects will provide critical insights for better evaluation and thus safer use of nanomaterials, in particular those having been pre-modified with other agents.

A novel fluorinated triazole derivative suppresses macrophage activation and alleviates experimental colitis via a Twist1-dependent pathway

Graphical abstract Figure. No caption available. &NA; Hyperactivated macrophages play a key role in the initiation and perpetuation of mucosal inflammation in Crohns disease (CD). Increasing evidence suggests that the basic helix‐loop‐helix (bHLH) repressor Twist1 can suppress activation of nuclear factor‐&kgr;B (NF‐&kgr;B) and the subsequent production of TNF‐&agr;, which are both essential elements of macrophage activation. Thus, developing novel therapeutic strategies to enhance Twist1 expression and to inhibit macrophage activation may be beneficial for CD treatment. In the present study, a series of trifluoroethyl thiazolo[3,2‐b][1,2,4]triazole derivatives were used to investigate their potential anti‐inflammatory activities and the underlying mechanism. In a biological activity screen, compound 7# (Thiazolo[3,2‐b][1,2,4]triazole‐5‐methanamine, 6‐phenyl‐&agr;‐(trifluoromethyl)‐, (&agr;R)‐, TT‐TFM) suppressed the activation of macrophages. Consistent with the in vitro data, TT‐TFM protected against 2,4,6‐trinitrobenzene sulfonic acid (TNBS), dextran sulfate sodium (DSS)‐induced acute colitis and IL‐10 knockout (KO) chronic colitis, as judged by body weight changes and colonic pathological damage. A mechanistic study based on microarray analysis and gene interference experiments indicated that TT‐TFM exerted anti‐inflammatory effects by enhancing Twist1 expression and subsequently blocking the NF‐&kgr;B/TNF‐&agr; pathway. In addition, pretreatment with lentiviruses encoding shRNA targeting Twist1 could abolish the therapeutic effect of TT‐TFM in TNBS colitis. Ultimately, TT‐TFM showed anti‐colitis activity by reducing NF‐&kgr;B activation and the TNF‐&agr; level by promoting Twist1 expression; thus, TT‐TFM may offer a therapeutic strategy for CD patients.

Expression of XBP1s in fibroblasts is critical for TiAl6 V4 particle-induced RANKL expression and osteolysis.

Wear particle‐induced osteolysis is a major cause of aseptic loosening, which is one of the most common reasons for total hip arthroplasty (THA) failure. Previous studies have shown that the expression of Receptor activation of nuclear factor (NF)‐kB (RANKL) by fibroblasts in periprosthetic membrane played a crucial role in wear particle‐induced osteolysis. However, the underlying mechanism of RANKL expression remains largely unknown. In the present study, we investigated the effect of TiAl6V4 particle (TiPs)‐induced XBP1s (spliced form of X‐box binding protein 1) on RANKL expression and osteoclastogenesis both in vitro and in vivo. The levels of XBP1s in peri‐implant membrane, animal models, and TiPs‐stimulated fibroblasts were determined by western blots. To assess the effect of XBP1s on RANKL expression, fibroblasts were treated with both a small interfering RNA (siRNA) and an inhibitor of XBP1 prior to exposure to TiPs. The effect of XBP1s on osteoclasts formation was determined by tartrate‐resistant acid phosphatase (TRAP) staining in vitro osteoclastogenesis assay and in animal models. The resorption of bone was assessed by micro‐computed tomography (micro‐CT) with three‐dimensional reconstruction. Our results demonstrated that XBP1s was activated in periprosthetic membrane, mouse calvaria models, and TiPs‐stimulated human synovial fibroblasts. Further, inhibition of XBP1s decreased the expression of RANKL and osteoclasts formation in vitro. In mouse calvaria models, both of the osteoclastogenesis and osteolysis were inhibited XBP1s inhibitor. Our results suggested that XBP1s mediated TiPs‐induced of RANKL expression in fibroblasts, and down regulating XBP1s may represent a potential therapy for wear particle‐induced osteolysis.