Lipocalin-2 Exacerbates Lupus Nephritis by Promoting Th1 Cell Differentiation.

BACKGROUND: Lipocalin-2 (LCN2) is an indicator of the severity of lupus nephritis (LN) and plays a pivotal role in immune responses, but it is not known if its effect on LN pathogenesis derives from regulating the immune imbalance of T lymphocyte subsets. METHODS: The expression of LCN2 in T cells and kidneys was assessed in renal biopsies from patients with LN. We investigated the relationship between LCN2 levels and development of LN and systemic illness by injecting anti-LCN2 antibodies into MRL/lpr mice and analyzing pristane-treated LCN2-/- mice. RESULTS: LCN2 is highly expressed in CD4+ T cells and in renal tissues, and is associated with severe renal damage in patients with LN and in mice with experimental lupus. LCN2 promotes IFN-γ overexpression in CD4+ T cells through the IL-12/STAT4 pathway in an autocrine or paracrine manner. Both neutralization of LCN2 in MRL/lpr mice and genetic depletion of LCN2 in pristane-induced lupus mice greatly ameliorate nephritis. The frequency and number of splenic and renal Th1 cells decrease in proportion to LN disease activity. Conversely, administration of LCN2 exacerbates the disease with significantly higher renal activity scores and increased numbers of Th1 cells. CONCLUSIONS: LCN2 plays a crucial role in Th1 cell differentiation, and may present a potential therapeutic target for LN.

Mesenchymal stem cells prevent podocyte injury in lupus-prone B6.MRL-Faslpr mice via polarizing macrophage into an anti-inflammatory phenotype.

BACKGROUND: Podocyte injury plays a pathogenic role in the development of lupus nephritis (LN). Mesenchymal stem cells (MSCs) have shown promising therapeutic potential for LN. However, whether MSCs can prevent podocyte injury in LN remains unknown. METHODS: Human umbilical cord-derived MSCs (UC-MSCs) were infused into lupus-prone B6.MRL-Faslpr (B6.lpr) mice to investigate the influences of UC-MSCs on podocyte injury in LN. Podocytes and macrophages were co-cultured with UC-MSCs in vitro to study the mechanism by which UC-MSC protect podocytes. We further explored the effects of UC-MSCs on macrophage polarization. RESULTS: We found that UC-MSCs promoted the expression of podocyte-specific markers, podocin and synaptopodin, in lupus-prone B6.lpr mice, along with the improvement of lupus renal pathology in terms of reduced IgG and C3 deposition in glomeruli and decreased anti-dsDNA antibody level. Besides, UC-MSC treatment decreased podocyte foot process effacement, as UC-MSCs-treated macrophages led to less podocyte injury in vitro. Interestingly, we further found that UC-MSCs-treated macrophages exhibited an anti-inflammatory phenotype with higher expression of CD206, and lower expression of tumor necrosis factor-α and interleukin-1ß. Additionally, UC-MSCs-treated lupus mice showed reduced renal macrophage infiltration and elevated CD206 expression in kidney. CONCLUSIONS: Our results demonstrated that UC-MSCs ameliorated LN by preventing podocyte injury possibly through reducing macrophage infiltration and polarizing macrophage into an anti-inflammatory phenotype.

Mesenchymal stem cell transplantation ameliorates Sjögren's syndrome via suppressing IL-12 production by dendritic cells.

BACKGROUND: Mesenchymal stem cells (MSCs) have been demonstrated to be effective in treating autoimmune diseases including Sjögren's syndrome (SS). We aim to compare the effects of MSC transplantation (MSCT) and the role of serum interleukin-12 (IL-12) in SS. METHODS: IL-12 levels were measured by ELISA. IL-12 mRNA transcripts in dendritic cells (DCs) were determined by RT-PCR. After co-culturing with MSCs, IL-12 mRNA transcripts in mouse and human DCs were detected. Non-obese diabetic (NOD) mice received MSCT, recombinant IL-12, or anti-IL-12 mAb treatment, respectively. Then, salivary flow rates, histopathology of salivary glands, and splenic lymphocyte subsets were examined in these mice. RESULTS: IL-12 levels in the serum were significantly increased in SS patients and positively correlated with the EULAR 2010 Sjögren's syndrome disease activity index. DCs from SS patients produced more IL-12 than those from the control. Likewise, IL-12 treatment in NOD mice significantly decreased salivary flow rates and promoted lymphocyte infiltration in salivary glands. IL-12 antibodies downregulated Th1, Th17, and Tfh cell. MSCT enhanced salivary flow rates and decreased lymphocyte infiltrations in salivary glands of NOD mice. MSCT downregulated Th17 and Tfh cells but upregulated regulatory T cells. MSCT reduced IL-12 productions in both SS patients and mice. CONCLUSION: Our results indicate that MSCs ameliorate SS possibly via suppressing IL-12 production in DCs and that IL-12 could be a potential therapeutic target of SS. TRIAL REGISTRATION: NTC00953485 . Registered June 2009.

Mesenchymal stem cells induced CD4+ T cell apoptosis in treatment of lupus mice.

Umbilical cord-derived mesenchymal stem cell transplantation (UCMSCT) has been used to treat human autoimmune diseases like lupus for example, but little is known about its effect on cell apoptosis. Here we evaluated the efficacy of UCMSCT for lupus treatment and explored the mechanism by which mesenchymal stem cells (MSCs) modulate T cell apoptosis in lupus mice. 1 × 106 human umbilical cord-derived mesenchymal stem cells (UC-MSCs) were injected into B6.MRL-Faslpr (B6.lpr) mice via tail vein. 6 h, 24 h or 4 weeks later, the mice were sacrificed and the apoptosis of lymphocytes in peripheral blood and spleen were detected by flow cytometry. The immune cell subpopulations in spleen were also measured at 6 h and 24 h, respectively. The therapeutic effects were assessed after 4 weeks. The frequency of peripheral blood CD4+ T cell apoptosis was reduced in lupus-prone B6.lpr mice. UCMSCT alleviated the disease phenotypes in B6.lpr mice, decreased the ratio of Th1 as well as Th2 cells, and increased percentages of apoptotic CD4+ T cells in vivo and vitro. Collectively, our findings unravel that UCMSCT alleviate lupus disease and reverse immune imbalance possibly by promoting T cell apoptosis in B6.lpr mice.

Mesenchymal Stem Cells Control Complement C5 Activation by Factor H in Lupus Nephritis.

Lupus nephritis (LN) is one of the most severe complications of systemic lupus erythematosus (SLE) caused by uncontrolled activation of the complement system. Mesenchymal stem cells (MSCs) exhibit clinical efficacy for severe LN in our previous studies, but the underlying mechanisms of MSCs regulating complement activation remain largely unknown. Here we show that significantly elevated C5a and C5b-9 were found in patients with LN, which were notably correlated with proteinuria and different renal pathological indexes of LN. MSCs suppressed systemic and intrarenal activation of C5, increased the plasma levels of factor H (FH), and ameliorated renal disease in lupus mice. Importantly, MSCs transplantation up-regulated the decreased FH in patients with LN. Mechanistically, interferon-α enhanced the secretion of FH by MSCs. These data demonstrate that MSCs inhibit the activation of pathogenic C5 via up-regulation of FH, which improves our understanding of the immunomodulatory mechanisms of MSCs in the treatment of lupus nephritis.

Mesenchymal Stem Cells Promote the Osteogenesis in Collagen-Induced Arthritic Mice through the Inhibition of TNF-α.

OBJECTIVE: To investigate the effects of umbilical cord mesenchymal stem cell (UC-MSC) transplantation on joint damage and osteoporosis in collagen-induced arthritis (CIA) mice and to explore the mechanisms by which UC-MSCs modulate the osteogenic differentiation. METHODS: CIA mice were divided into the following treated groups: UC-MSC transplantation group, antitumor necrosis factor- (TNF-) α group, and zoledronic acid (ZA) group. Microcomputed tomography (micro-CT) was used to analyze the bone morphology parameters. Osteogenic differentiation of treated CIA mice was determined. Bone marrow mesenchymal stem cells (BM-MSCs) from CIA mice were treated with TNF-α in vitro to explore their effects on osteogenesis. RESULTS: The arthritis score was significantly reduced in the UC-MSC transplantation and anti-TNF-α-treated CIA groups, compared with control mice (P < 0.001). Micro-CT showed that CIA mice developed osteoporosis at 12 weeks after immunization. The bone morphology parameters were partially improved in UC-MSC-treated CIA mice. Impaired osteogenic differentiation functions were indicated by decreased ALP activity (P < 0.001) and reduced mRNA and protein levels of osteogenic marker genes (P < 0.05) in CIA mice compared with DBA/1 mice. UC-MSC treatment significantly upregulated the impaired osteogenic differentiation ability in CIA mice. Meanwhile, the serum TNF-α level was decreased significantly in the UC-MSC group. The osteogenesis was reduced with the addition of TNF-α in vitro. CONCLUSION: This study demonstrated that UC-MSC transplantation not only significantly improved the joint damage but also played a beneficial role in osteoporosis in CIA mice. Mechanistically, the improved osteogenic differentiation of CIA under UC-MSC treatment may be achieved by inhibition of TNF-α.

Human Umbilical Cord Mesenchymal Stem Cells Inhibit T Follicular Helper Cell Expansion Through the Activation of iNOS in Lupus-Prone B6.MRL-Faslpr Mice.

The aberrant generation or activation of T follicular helper (Tfh) cells contributes to the pathogenesis of systemic lupus erythematosus (SLE), yet little is known about how these cells are regulated. In this study, we demonstrated that the frequency of Tfh cells was increased in lupus-prone B6.MRL-Faslpr (B6.lpr) mice and positively correlated to plasma cell proportions and serum total IgG as well as anti-dsDNA antibody levels. Transplantation of mesenchymal stem cells derived from Wharton's jelly of human umbilical cords (hUC-MSCs) ameliorated lupus symptoms in B6.lpr mice, along with decreased percentages of Tfh cells. In vitro studies showed that the differentiation and proliferation of Tfh cells were markedly suppressed by hUC-MSCs. The production of inducible nitric oxide synthase (iNOS) was dramatically upregulated in hUC-MSCs when cocultured with CD4+ T cells directly, while adding the specific inhibitor of iNOS into the coculture system significantly reversed the inhibitory effect of hUC-MSCs on Tfh cell generation. Interestingly, the efficacy of hUC-MSCs in inhibiting Tfh cells was impaired in the Transwell system, with the reduction of iNOS in both mRNA and protein levels. Taken together, our findings suggest that hUC-MSCs could effectively inhibit Tfh cell expansion through the activation of iNOS in lupus-prone B6.lpr mice, which is highly dependent on cell-to-cell contacts.