Modified BuShenYiQi formula alleviates experimental allergic asthma in mice by negative regulation of type 2 innate lymphoid cells and CD4+ type 9 helper T cells and the VIP-VPAC2 signalling pathway

CONTEXT

Modified BuShenYiQi formula (M-BYF) is derived from BuShenYiQi formula, used for the treatment of allergic asthma. The exact effect and mechanism of M-BYF on the improvement of asthma remain unclear.

OBJECTIVE

We investigated the mechanism underlying the therapeutic effect of M-BYF on allergic asthma.

MATERIALS AND METHODS

The asthma model was established in female BALB/c mice that were sensitized and challenged with ovalbumin (OVA). Mice in the treated groups were orally treated once a day with M-BYF (7, 14 and 28 g/kg/d) or dexamethasone before OVA challenge. Control and Model group received saline. Pathophysiological abnormalities and percentages of lung type 2 innate lymphoid cells (ILC2s) and Th9 cells were measured. Expression levels of type 2 cytokines and transcription factors required for these cells function and differentiation were analysed. Expression of vasoactive intestinal polypeptide (VIP)-VPAC2 signalling pathway-related proteins, and percentages of VIP expressing (VIP⁺) cells and VPAC2, CD90 co-expressing (VPAC2⁺CD90⁺) cells were detected.

RESULTS

M-BYF alleviated airway hyperresponsiveness, inflammation, mucus hypersecretion and collagen deposition in asthmatic mice. M-BYF down-regulated percentages of ILC2s and Th9 cells with lower expression of GATA3, PU.1 and IRF4, reduced IL-5, IL-13, IL-9 and VIP production. The decrease in the expression of VIP-VPAC2 signalling pathway and percentages of VIP⁺ cells, VPAC2⁺CD90⁺ cells were observed after M-BYF treatment. The LD₅₀ value of M-BYF was higher than 90 g/kg.

DISCUSSION AND CONCLUSIONS

M-BYF alleviated experimental asthma by negatively regulating ILC2s and Th9 cells and the VIP-VPAC2 signalling pathway. These findings provide the theoretical basis for future research of M-BYF in asthma patient population.

Psychological stress impairs IL22-driven protective gut mucosal immunity against colonising pathobionts

Crohn's disease is an inflammatory disease of the gastrointestinal tract characterized by an aberrant response to microbial and environmental triggers. This includes an altered microbiome dominated by Enterobacteriaceae and in particular adherent-invasive E. coli (AIEC). Clinical evidence implicates periods of psychological stress in Crohn's disease exacerbation, and disturbances in the gut microbiome might contribute to the pathogenic mechanism. Here we show that stress-exposed mice develop ileal dysbiosis, dominated by the expansion of Enterobacteriaceae. In an AIEC colonisation model, stress-induced glucocorticoids promote apoptosis of CD45+CD90+ cells that normally produce IL-22, a cytokine that is essential for the maintenance of ileal mucosal barrier integrity. Blockade of glucocorticoid signaling or administration of recombinant IL-22 restores mucosal immunity, prevents ileal dysbiosis, and blocks AIEC expansion. We conclude that psychological stress impairs IL-22-driven protective immunity in the gut, which creates a favorable niche for the expansion of pathobionts that have been implicated in Crohn's disease. Importantly, this work also shows that immunomodulation can counteract the negative effects of psychological stress on gut immunity and hence disease-associated dysbiosis.

Innate Type 2 Response to Aspergillus fumigatus in a Murine Model of Atopic Dermatitis-like Skin Inflammation

BACKGROUND

Atopic dermatitis (AD) is a chronic and relapsing inflammatory skin disease mediated by T helper type 2 (Th2) cells in acute phase. Group 2 innate lymphoid cells (ILCs) play a role in the initiation of the Th2 response. Although mold exposure is associated with the development of AD, studies on the underlying mechanisms are lacking. This study investigated whether group 2 ILCs are involved in inflammation in AD-like skin induced by Aspergillus fumigatus (Af).

METHODS

We investigated changes of group 2 ILCs population in Af-induced AD-like skin lesions. To induce AD-like skin lesions, Af extracts were applied to the dorsal skin of BALB/c and Rag1^-/- mice five times per week, with repeat exposures at 2-week intervals.

RESULTS

The clinical parameters were higher in the Af-treated group than in the control group. Histologic findings revealed epiderrmal and dermal thickening as well as eosinophil and mast cell infiltration into the skin of Af-treated mice. Populations of group 2 ILCs in the skin were also significantly higher in the Af-treated group. In addition, interleukin-33 mRNA expression was significantly higher in the skin lesions of the Af-treated mice. In the Rag1^-/- mice lacking mature lymphocytes, AD-like skin lesions were still induced by Af and ILCs depletion using an anti-CD90.2 mAb lowered the Af-induced inflammatory response.

CONCLUSIONS

Group 2 ILCs may play a role in a murine model of Af-induced AD-like skin lesions.

Langerin+ DCs regulate innate IL-17 production in the oral mucosa during Candida albicans-mediated infection

The opportunistic fungal pathogen Candida albicans frequently causes diseases such as oropharyngeal candidiasis (OPC) in immunocompromised individuals. Although it is well appreciated that the cytokine IL-17 is crucial for protective immunity against OPC, the cellular source and the regulation of this cytokine during infection are still a matter of debate. Here, we directly visualized IL-17 production in the tongue of experimentally infected mice, thereby demonstrating that this key cytokine is expressed by three complementary subsets of CD90+ leukocytes: RAG-dependent αβ and γδ T cells, as well as RAG-independent ILCs. To determine the regulation of IL-17 production at the onset of OPC, we investigated in detail the myeloid compartment of the tongue and found a heterogeneous and dynamic mononuclear phagocyte (MNP) network in the infected tongue that consists of Zbtb46-Langerin- macrophages, Zbtb46+Langerin+ dendritic cells (DCs) and Ly6C+ inflammatory monocytes. Of those, the Langerin+ DC population stands out by its unique capacity to co-produce the cytokines IL-1β, IL-6 and IL-23, all of which promote IL-17 induction in response to C. albicans in the oral mucosa. The critical role of Langerin+ DCs for the innate IL-17 response was confirmed by depletion of this cellular subset in vivo, which compromised IL-17 induction during OPC. In conclusion, our work revealed key regulatory factors and their cellular sources of innate IL-17-dependent antifungal immunity in the oral mucosa.

A Novel Prime and Boost Regimen of HIV Virus-Like Particles with TLR4 Adjuvant MPLA Induces Th1 Oriented Immune Responses against HIV

HIV virus-like particles (VLPs) present the HIV envelope protein in its native conformation, providing an ideal vaccine antigen. To enhance the immunogenicity of the VLP vaccine, we sought to improve upon two components; the route of administration and the additional adjuvant. Using HIV VLPs, we evaluated sub-cheek as a novel route of vaccine administration when combined with other conventional routes of immunization. Of five combinations of distinct prime and boost sequences, which included sub-cheek, intranasal, and intradermal routes of administration, intranasal prime and sub-cheek boost (IN+SC) resulted in the highest HIV-specific IgG titers among the groups tested. Using the IN+SC regimen we tested the adjuvant VesiVax Conjugatable Adjuvant Lipid Vesicles (CALV) + monophosphoryl lipid A (MPLA) at MPLA concentrations of 0, 7.5, 12.5, and 25 μg/dose in combination with our VLPs. Mice that received 12.5 or 25 μg/dose MPLA had the highest concentrations of Env-specific IgG2c (20.7 and 18.4 μg/ml respectively), which represents a Th1 type of immune response in C57BL/6 mice. This was in sharp contrast to mice which received 0 or 7.5 μg MPLA adjuvant (6.05 and 5.68 μg/ml of IgG2c respectively). In contrast to IgG2c, MPLA had minor effects on Env-specific IgG1; therefore, 12.5 and 25 μg/dose of MPLA induced the optimal IgG1/IgG2c ratio of 1.3. Additionally, the percentage of germinal center B cells increased significantly from 15.4% in the control group to 31.9% in the CALV + 25 μg MPLA group. These mice also had significantly more IL-2 and less IL-4 Env-specific CD8⁺ T cells than controls, correlating with an increased percentage of Env-specific central memory CD4⁺ and CD8⁺ T cells. Our study shows the strong potential of IN+SC as an efficacious route of administration and the effectiveness of VLPs combined with MPLA adjuvant to induce Env specific Th1-oriented HIV-specific immune responses.

Selection of natural autoreactive B cells

Natural antibodies produced by CD5+ B1 B cells include anti-thymocyte autoantibody (ATA). Transgenic mice bearing the Ig-μ heavy chain of a prototypic ATA, V(H)3609Vκ21c, demonstrated a critical requirement for self-antigen in the accumulation of ATA B cells and production of high levels of serum ATA. Further work with ATA-μκ transgenic mice revealed that, while development of most B cells were blocked at an immature stage in spleen, some mature ATA B cells were present. ATA-μκ transgenic mice with varying levels of Thy-1 autoantigen showed a clear relationship between BCR crosslinking and B cell fate, with low levels generating marginal zone ATA B cells and complete antigen absence allowing maturation to follicular ATA B cells. Finally, different fates of developing ATA B cells encountering high levels self-antigen may be accounted for by variations in the response of newly formed B cells arising from foetal and adult development.

Mesenchymal stem cells from rats with chronic kidney disease exhibit premature senescence and loss of regenerative potential

Mesenchymal stem cell (MSC) transplantation has the potential for organ repair. Nevertheless, some factors might lessen the regenerative potential of MSCs, e.g. donor age or systemic disease. It is thus important to carefully assess the patient's suitability for autologous MSC transplantation. Here we investigated the effects of chronic kidney disease (CKD) on MSC function. We isolated bone marrow MSCs from remnant kidney rats (RK) with CKD (CKD-RK-MSC) and found signs of premature senescence: spontaneous adipogenesis, reduced proliferation capacity, active senescence-associated-β-galactosidase, accumulation of actin and a modulated secretion profile. The functionality of CKD-RK-MSCs in vivo was tested in rats with acute anti-Thy1.1-nephritis, where healthy MSCs have been shown to be beneficial. Rats received healthy MSCs, CKD-RK-MSC or medium by injection into the left renal artery. Kidneys receiving healthy MSCs exhibited accelerated healing of glomerular lesions, whereas CKD-RK-MSC or medium exerted no benefit. The negative influence of advanced CKD/uremia on MSCs was confirmed in a second model of CKD, adenine nephropathy (AD). MSCs from rats with adenine nephropathy (CKD-AD-MSC) also exhibited cellular modifications and functional deficits in vivo. We conclude that CKD leads to a sustained loss of in vitro and in vivo functionality in MSCs, possibly due to premature cellular senescence. Considering autologous MSC therapy in human renal disease, studies identifying uremia-associated mechanisms that account for altered MSC function are urgently needed.

Preparation and Functional Analysis of Tumor-Infiltrating Stroma Cells Using Bone Marrow Chimera Mice

Tumor-infiltrating stroma cells (TISC) as well as tumors themselves are thought to be involved in tumor-related immunosuppression, which is one of the critical mechanisms of tumor escape from immune surveillance. However, preparation of TISC is difficult because of the small proportion of TISC in established tumors. Thus, the cells thought to be involved in tumor-related immunosuppression are generally prepared from spleens or draining lymph nodes in tumor-bearing mice. In this study, we developed a method for directly preparing TISC from established tumors in order to analyze their function. Using green fluorescent protein (GFP) transgenic (Tg) mice and C57BL/6 mice transplanted with bone marrow (BM) cells of GFPTg mice, we detected three subpopulations of TISC: one is compatible with immature myeloid cells (ImC) derived from BM and the two other subpopulations, CD11b(+) cells and CD11b(-) cells, do not originate from BM. The TISC including these subpopulations but not each subpopulation independently after culturing with tumors in the presence of GM-CSF could suppress T cell proliferation induced by anti-CD3. In our system, tumors did not inhibit T cell responses directly, but unknown factors from tumors affected immunosuppression by TISC.

Expression of integrin α2 receptor in human cord blood CD34+CD38-CD90+ stem cells engrafting long-term in NOD/SCID-IL2Rγ(c) null mice

Human hematopoietic stem cells reside in the CD34+CD38-CD90+ population in cord blood and bone marrow. However, this cell fraction is heterogeneous, and the phenotype of the rare primitive stem cells remains poorly defined. We here report that primitive cord blood CD34+CD38-CD90+ stem cells, with the ability to reconstitute NOD/SCID-IL2Rγ(c) null (NSG) mice long-term, at 24 weeks after transplantation, can be prospectively isolated at an increased purity by using integrin α2 receptor as an additional stem cell marker. Using a limiting dilution transplantation assay, we found a highly significant enrichment of multilineage reconstituting stem cells in the CD34+CD38-CD90+ cell fraction expressing the integrin α2 receptor, with a frequency of 1/29 cells, as compared to a frequency of 1/157 in the corresponding integrin α2- cells. In line with this, long-term reconstituting stem cells within the cord blood CD34+CD38- cell population were significantly enriched in the integrin α2+ fraction, while stem cells and progenitors reconstituting short-term, at 8-12 weeks, were heterogeneous in integrin α2 expression. Global gene expression profiling revealed that the lineage-marker negative (Lin-) CD34+CD38-CD90+CD45RA- integrin α2+ cell population was molecularly distinct from the integrin α2- cell population and the more mature Lin-CD34+CD38-CD90-CD45RA- cell population. Our findings identify integrin α2 as a novel stem cell marker, which improves prospective isolation of the primitive human hematopoietic stem cells within the CD34+CD38-CD90+ cell population for experimental and therapeutic stem cell applications.

MHC class I antigen presentation of DRiP-derived peptides from a model antigen is not dependent on the AAA ATPase p97

CD8⁺ T cells are responsible for killing cells of the body that have become infected or oncogenically transformed. In order to do so, effector CD8⁺ T cells must recognize their cognate antigenic peptide bound to a MHC class I molecule that has been directly presented by the target cell. Due to the rapid nature of antigen presentation, it is believed that antigenic peptides are derived from a subset of newly synthesized proteins which are degraded almost immediately following synthesis and termed Defective Ribosomal Products or DRiPs. We have recently reported on a bioassay which can distinguish antigen presentation of DRiP substrates from other forms of rapidly degraded proteins and found that poly-ubiquitin chain disassembly may be necessary for efficient DRiP presentation. The AAA ATPase p97 protein is necessary for efficient cross-presentation of antigens on MHC class I molecules and plays an important role in extracting mis-folded proteins from the endoplasmic reticulum. Here, we find that genetic ablation or chemical inhibition of p97 does not diminish DRiP antigen presentation to any great extent nor does it alter the levels of MHC class I molecules on the cell surface, despite our observations that p97 inhibition increased the levels of poly-ubiquitinated proteins in the cell. These data demonstrate that inhibiting poly-ubiquitin chain disassembly alone is insufficient to abolish DRiP presentation.

[Long-term expansion of multipotent mesenchymal stromal cells under reduced oxygen tension]

We have shown that the decrease in oxygen tension in the culture medium of multipotent mesenchymal stromal cells (MMSCs) results in a short-term reduction in the proportion of CD73(+)-cells in the population, without effecting the number of cells expressing other constitutive surface markers (CD90 and CD105). In this case, the heterogeneity of the cell population declined: large spread cells disappeared. The proliferative activity of MMSCs significantly increased and remained stable in conditions in which the oxygen content was close to the tissue oxygen levels (5% O2). At lower oxygen concentration, proliferative activity of the cells gradually reduced from passages 3-4. The increase in proliferative activity was not accompanied by increased expression of telomerase gene indicateding the alsance of cell transformation. However, genome-wide analysis of MMSC gene expression level revealed changes in expression of cyclins (CCND2 and PCNA), regulatory subunit cyclin-dependent kinase (CKS2) and an inhibitor of cyclin-dependent kinase (CDKN2C), regulating the cell cycle, which is obviously facilitated the increase in the proliferative capacity of cells at lower oxygen tension.

[FTY720 attenuates rat anti-Thy-1 mesangial proliferative glomerulonephritis by inhibition of transforming growth factor β1-connective tissue growth factor pathway]

OBJECTIVE

To investigate whether FTY720 inhibits rat mesangial proliferation and extracellular matrix expansion through suppression of transforming growth factor β1-connective tissue growth factor (TGFβ1-CTGF) pathway, and to explore experimental evidence for its effect on mesangial proliferative glomerulonephritis.

METHODS

A rat model of anti-Thy-1 mesangial proliferative glomerulonephritis was established and FTY720 intervention was performed. Periphery blood lymphocyte count, urine protein excretion, glomerular mesangial proliferation, protein and gene expression of TGFβ1 and CTGF and extracellular matrix protein including fibronectin, laminin and collagen IV in isolated glomeruli were documented at 1, 3 and 7 days after injection of anti-Thy-1 antibody.

RESULTS

The model group developed proteinuria at 1, 3 and 7 days after injection of anti-Thy-1 antibody, which were significantly higher [(27.9 ± 7.3), (63.5 ± 18.8) and (52.4 ± 15.4)mg/d, respectively] than those in the control group [(8.4 ± 2.4), (8.4 ± 2.1) and (10.4 ± 3.2) mg/d; respectively, P < 0.01]. FTY720 intervention group showed significantly decreased proteinuria at 3 and 7 days after injection [(31.4 ± 7.0), (25.5 ± 7.7) mg/d, respectively] than model group (P < 0.01), although higher than the control group (P < 0.01). After intervention for 3 and 7 days, FTY720 significantly down-regulated both TGFβ1 and CTGF gene and protein expression in cultured glomeruli, and suppressed the production of glomerular extracellular matrix protein secretion, leading to attenuated mesangial cell proliferation and extracellular matrix expansion in rat anti-Thy-1 mesangial proliferative glomerulonephritis.

CONCLUSION

FTY720 significantly attenuates mesangial proliferation and extracellular matrix expansion through inhibition of TGFβ1-CTGF pathway in rat, and thus ameliorates the development of anti-Thy-1 mesangial proliferative glomerulonephritis.

[Expression of neonatal Fc receptor on human nephritis and rat nephritis models]

OBJECTIVE

To study the expression of neonatal Fc receptor in podocytes in human nephritis and immune-induced rat nephritis models: anti-Thy1.1 nephritis and Heymann nephritis.

METHODS

Thirty-nine cases of renal biopsies were enrolled from September 2009 to February 2010, including 8 cases of minimal change disease, 4 cases of focal segmental glomerulosclerosis, 9 cases of membranous nephropathy, 12 cases of IgA nephropathy and 6 cases of lupus nephritis. Five normal kidney tissue samples adjacent to renal clear-cell carcinoma were served as normal controls. Laser capture microdissection and real-time RT-PCR were used to assess the expression level of FcRn mRNA in glomeruli of various glomerulonephritides, and immunohistochemistry (IHC) of FcRn by SuperVision method was performed. In addition, rat models of mesangial proliferative nephritis (anti-Thy1.1 nephritis) and passive membranous nephropathy (Heymann nephritis) were established and FcRn was examined in renal tissues by IHC.

RESULTS

The FcRn mRNA level in lupus nephritis was statistically higher than that of normal controls (P < 0.05). FcRn protein expression by IHC was seen in lupus nephritis (6/6), membranous nephropathy (6/9) and IgA nephropathy (7/12), significantly higher than that of normal controls (0/5), P < 0.05. Minimal change disease and focal segmental glomerular sclerosis showed minimal or none expression of FcRn (1/8, 0/4 respectively) and not statistically difference from that of normal controls. Furthermore, FcRn expression in podocytes was detected in rat anti-Thy1.1 (3/5) and Heymann nephritis models (2/7) but was not detected in normal controls.

CONCLUSIONS

Expression of FcRn in podocytes was up-regulated in immune-induced human nephritis and rat nephritis models of anti-Thy1.1 nephritis and Heymann nephritis. FcRn may play a role in the development of immune-induced glomerulonephritis.

Thy1+ NK [corrected] cells from vaccinia virus-primed mice confer protection against vaccinia virus challenge in the absence of adaptive lymphocytes

While immunological memory has long been considered the province of T- and B- lymphocytes, it has recently been reported that innate cell populations are capable of mediating memory responses. We now show that an innate memory immune response is generated in mice following infection with vaccinia virus, a poxvirus for which no cognate germline-encoded receptor has been identified. This immune response results in viral clearance in the absence of classical adaptive T and B lymphocyte populations, and is mediated by a Thy1⁺ subset of natural killer (NK) cells. We demonstrate that immune protection against infection from a lethal dose of virus can be adoptively transferred with memory hepatic Thy1⁺ NK cells that were primed with live virus. Our results also indicate that, like classical immunological memory, stronger innate memory responses form in response to priming with live virus than a highly attenuated vector. These results demonstrate that a defined innate memory cell population alone can provide host protection against a lethal systemic infection through viral clearance.

Immunological memory is a hallmark of adaptive immunity and provides the basis for our ability to become ‘immune’ to pathogens to which we have previously been exposed, and provides the basis for vaccination. For decades, the paradigm held that only the classical adaptive lymphocytes were capable of forming and maintaining protective immunological memory. Recently, several papers have shown the capacity of an innate cell population, a subset of natural killer (NK) cells, to exhibit certain aspects of immunological memory. Here we show that innate memory forms in response to infection with vaccinia virus and resides in a discrete subset of NK cells. We further demonstrate that this innate memory provides significant host protection against a subsequent systemic infection with a lethal dose of vaccinia virus, in some cases resulting in the complete clearance of detectable virus. We also demonstrate that priming with live, replicating virus stimulates innate memory more robustly than a highly attenuated vector. These findings shed new light on this emergent area of immunology, and hold significant implications for harnessing innate memory as part of creating novel vaccination strategies.

Mesenchymal stromal cells improve renal injury in anti-Thy 1 nephritis by modulating inflammatory cytokines and scatter factors

MSC (mesenchymal stromal cells) can differentiate into renal adult cells, and have anti-inflammatory and immune-modulating activity. In the present study, we investigated whether MSC have protective/reparative effects in anti-Thy1 disease, an Ab (antibody)-induced mesangiolysis resulting in mesangioproliferative nephritis. We studied five groups of rats: (i) rats injected with anti-Thy1.1 Ab on day 0 (group A); (ii) rats injected with anti-Thy1.1 Ab on day 0+MSC on day 3 (group B); (iii) rats injected with anti-Thy1.1 Ab on day 0+mesangial cells on day 3 (group C); (iv) rats injected with saline on day 0+MSC on day 3 (group D); and (v) rats injected with saline on day 0 (group E). Rats were killed on days 1, 3, 7 and 14. MSC prevented the increase in serum creatinine, proteinuria, glomerular monocyte influx and glomerular histopathological injury. Furthermore, MSC suppressed the release of IL-6 (interleukin-6) and TGF-β (transforming growth factor-β), modulated glomerular PDGF-β (platelet-derived growth factor-β), and reset the scatter factors and their receptors, potentiating HGF (hepatocyte growth factor)/Met and inactivating MSP (macrophage-stimulating protein)/Ron (receptor origin nantaise). Few MSC were found in the kidney. These results indicate that MSC improve anti-Thy 1 disease not by replacing injured cells, but by preventing cytokine-driven inflammation and modulating PDGF-β and the scatter factors, i.e. systems that regulate movement and proliferation of monocytes and mesangial cells.

Distinct requirements for achievement of allotolerance versus reversal of autoimmunity via nonmyeloablative mixed chimerism induction in NOD mice

OBJECTIVES

Mixed hematopoietic chimerism is associated with islet allograft tolerance and may reverse autoimmunity. We developed low intensity regimens for the induction of mixed chimerism and examined the effects on autoimmunity in prediabetic nonobese diabetic (NOD) mice.

RESEARCH DESIGN AND METHODS

NOD mice received various combinations of total body irradiation, anti-CD154, anti-CD8alpha, anti-CD4, and anti-Thy1.2 monoclonal antibodies, with or without transplantation of C57BL/6 bone marrow cells and were followed up for development of diabetes, chimerism, and donor skin graft survival. Autoimmunity was assessed by histologic examination of salivary glands and pancreata.

RESULTS

Although conditioning alone prevented or delayed the onset of diabetes, stable mixed chimerism was required for the reversal of isletitis. Mixed chimerism and skin graft tolerance were achieved in NOD mice receiving anti-CD154 with bone marrow transplantation as the means of tolerizing peripheral CD4 T cells to alloantigens. However, isletitis was not reversed in allotolerant mixed chimeras prepared with this regimen.

CONCLUSIONS

Partial depletion of peripheral autoreactive NOD CD4 T cells is needed to achieve full reversal of isletitis by mixed chimerism induction from a protective donor strain, but it is not required for induction of specific tolerance to donor alloantigens. Thus, the requirements for tolerizing alloreactive and autoreactive NOD CD4 cells are distinct.

Contrasting effects of steroids and mizoribine on macrophage activation and glomerular lesions in rat thy-1 mesangial proliferative glomerulonephritis

BACKGROUND

Macrophages with a pro-inflammatory (M1) phenotype mediate renal injury in proliferative forms of glomerulonephritis, while alternatively activated (M2) macrophages are thought to be anti-inflammatory and promote repair. Glucocorticoids, the mainstay therapy for proliferative glomerulonephritis, can induce alternative macrophage activation in vitro, but it is unknown whether this occurs in vivo and if this is required for glucocorticoid responsiveness. In addition, clinical studies have suggested that the ability of mizoribine (MZR) to suppress steroid-resistant proliferative glomerulonephritis may operate via inhibiting pro-inflammatory macrophage activation.

METHODS

This study examined prednisolone (PSL) and/or MZR treatment of rat Thy-1 disease - a model in which macrophages promote mesangial proliferative glomerulonephritis.

RESULTS

PSL treatment of Thy-1 nephritis induced an M2-like macrophage phenotype, but failed to modify mesangial hypercellularity and actually exacerbated global glomerulosclerosis. In contrast, MZR treatment reduced hypercellularity and glomerulosclerosis and suppressing both M1 and M2 markers of macrophage activation, with a selective reduction in CD169+ macrophages. Combined PSL/MZR treatment suppressed glomerular lesions and prevented steroid induction of an M2-like macrophage phenotype. In vitro, MZR prevented steroid induction of an M2 macrophage phenotype.

CONCLUSIONS

Glucocorticoid induced alternative macrophage activation failed to ameliorate rat mesangial proliferative glomerulonephritis, whereas MZR suppression of this disease model was attributed, in part, to inhibition of M1-like pro-inflammatory macrophage activation.

Apoptosis of glomerular mesangial cells induced by sublytic C5b-9 complexes in rats with Thy-1 nephritis is dependent on Gadd45 gamma upregulation

The complement C5b-9 complexes can result in cell apoptosis, but the mechanism of sublytic C5b-9-mediated glomerular mesangial cell (GMC) apoptosis in Thy-1 nephritis (Thy-1N) remains largely unclear. The Gadd45 gene is involved in the cellular response to DNA damage and can promote cell apoptosis. In this study, both Gadd45 gamma expression patterns and pathologic changes of renal tissue were examined in rat Thy-1N. Both Gadd45 gamma expression and GMC apoptosis were significantly decreased in Thy-1N rats upon the depletion of complement with cobra venom factor. Our in vitro studies showed that Gadd45 gamma over-expression increased sublytic C5b-9-induced GMC apoptosis, while Gadd45 gamma gene knockdown by siRNA greatly reduced GMC apoptosis. Moreover, Gadd45 gamma gene silencing in vivo markedly inhibited the pathologic changes in the renal tissue of Thy-1N rats. These data suggest that Gadd45 gamma gene expression is involved in regulating GMC apoptosis mediated by sublytic C5b-9 in Thy-1N.

Human CD34/CD90 ASCs are capable of growing as sphere clusters, producing high levels of VEGF and forming capillaries

Background

Human adult adipose tissue is an abundant source of mesenchymal stem cells (MSCs). Moreover, it is an easily accessible site producing a considerable amount of stem cells.

Methodology/Principal Findings

In this study, we have selected and characterized stem cells within the stromal vascular fraction (SVF) of human adult adipose tissue with the aim of understanding their differentiation capabilities and performance. We have found, within the SVF, different cell populations expressing MSC markers – including CD34, CD90, CD29, CD44, CD105, and CD117 – and endothelial-progenitor-cell markers – including CD34, CD90, CD44, and CD54. Interestingly, CD34⁺/CD90⁺ cells formed sphere clusters, when placed in non-adherent growth conditions. Moreover, they showed a high proliferative capability, a telomerase activity that was significantly higher than that found in differentiated cells, and contained a fraction of cells displaying the phenotype of a side population. When cultured in adipogenic medium, CD34⁺/CD90⁺ quickly differentiated into adipocytes. In addition, they differentiated into endothelial cells (CD31⁺/VEGF⁺/Flk-1⁺) and, when placed in methylcellulose, were capable of forming capillary-like structures producing a high level of VEGF, as substantiated with ELISA tests.

Conclusions/Significance

Our results demonstrate, for the first time, that CD34⁺/CD90⁺ cells of human adipose tissue are capable of forming sphere clusters, when grown in free-floating conditions, and differentiate in endothelial cells that form capillary-like structures in methylcellulose. These cells might be suitable for tissue reconstruction in regenerative medicine, especially when patients need treatments for vascular disease.

[Effects of adipose-derived stem cell transplantation on the angiogenesis and the expression of bFGF and VEGF in the brain post focal cerebral ischemia in rats]

AIM

To investigate the effects of adipose-derived stem cell (ADSC) transplantation on the angiogenesis in the brain post focal cerebral ischemia in rats.

METHODS

72 male adult Sprague-Dawley rats were randomly divided into 4 groups: sham-operated group, middle cerebral artery occlusion (MCAO) group, vehicle group and MCAO+ADSC-treated group (n=18). A permenant focal cerebral ischemia model was established with the modified Longa's method. ADSC were labeled by DAPI before transplantation. One day after right MCAO, 30 muL of cell suspension containing 1x10(6) cells were injected into the lateral ventricle of MCAO+ADSC-treated group and the same dose of PBS was given to the vehicle group. On D4, D7 and D14 after MCAO, the rats were killed to detect the regeneration of microvessel and the expression of bFGF and VEGF in ischemic region by immunohistochemistry and RT-PCR.

RESULTS

A lot of microvessel proliferate in the injured cortex reached peak in 2 weeks. The microvessel density in the brain tissues of rats treated with ADSC was higher than that in MCAO group and vehicle group (P<0.01). The expression of bFGF and VEGF in the brain tissues of MCAO+ADSC-treated group was higher than that in MCAO group and vehicle group on D4, D7 and D14 post MCAO.

CONCLUSION

The transplantation of ADSC can promote the revascularization of cerebral ischemia in rats partly by enhancing bFGF and VEGF synthesis in brain.

The profile of gene expression and role of nuclear factor kappa B on glomerular injury in rats with Thy-1 nephritis

Mesangioproliferative glomerulonephritis (MsPGN) is a disease of high incidence in humans. Rats with Thy-1 nephritis (Thy-1 N) are used as an animal model for studying MsPGN. Although several studies have demonstrated that many pathological factors could cause the injury of glomerular mesangial cells (GMCs) in Thy-1 N, changes of profile and the molecular mechanism of the disease (i.e. the role of transcription factors) at intervals remain unclear. The purpose of this study was to identify the changes in gene expression profile and to observe the role of nuclear factor kappa B (NF-kappaB) on the pathological change of renal tissue in Thy-1 N rats. Our results showed that the pathological changes of GMCs in Thy-1 N included three phases: apoptosis (40 min), necrosis (24 h) and proliferation (7 days). Concomitantly, at 40 min and on day 7, the up-regulation of 341 genes and 250 genes were observed, while 392 genes and 119 genes were down-regulated in Thy-1 N. Expression of interleukin (IL)-1beta, IL-6, proliferating cell nuclear antigen, alpha-smooth muscle actin, collagen type IV and excretion of urinary protein was increased in rats with Thy-1 N and decreased in pyrrolidine dithiocarbamate-treated rats with Thy-1 N. These data indicated that the significant changes in the gene profile were coupled with the pathological changes of Thy-1 N, and activation of NF-kappaB may contribute to the pathogenesis of GMCs apoptosis, proliferation, extracelluar matrix accumulation and proteinuria in Thy-1 N.

MDS: a stem cell disorder--but what exactly is wrong with the primitive hematopoietic cells in this disease?

Despite the various abnormalities identified in the immune system or the bone marrow microenvironment in patients with myelodysplastic syndrome (MDS), most of the investigation of this disorder has centered on the hematopoietic stem/progenitor compartment. It is generally written that MDS is a stem cell disorder, and there is certainly evidence supporting this view. However, whether it occurs in a cell with only myeloid multipotentiality (i.e., that involves megakaryocytic, erythroid and granulocytic/monocytic lineages) or occurs in a true stem cell is open to debate. The absence of an assay for human stem cells necessitates the use of surrogate markers for such cells, such as gene expression profiles, or the identification of specific genetic or epigenetic abnormalities that are found in multiple lineages. Clearly, the common cytogenetic and genetic abnormalities found in MDS are most indicative of a clonal myeloid disease similar to AML, rather than a lymphoid disease, and the often tri-lineage ineffective hematopoiesis and dysplasia are generally not found within the lymphoid compartment. Recent studies, using modern molecular detection techniques, have identified new recurring molecular lesions in these disorders but have not really unraveled its pathogenesis.

Effect of Suturing Technique on Corneal Xenograft Survival

PURPOSE

Understanding xenograft rejection is crucial for the potential introduction of xenotransplantation into clinical practice. Small-animal models play an essential role in this context and substantially contribute to our knowledge about mechanisms of xenograft rejection.

METHODS

Rat-to-mouse corneal xenografts were performed by using 2 suturing techniques. Sutures were left either as long or as short as possible to limit the extent of a nonspecific inflammatory response. Cyclosporine A (CsA), monoclonal antibody anti-T cells, and a specific inhibitor of inducible NO synthase (alone or in a combination with CsA) were tested as immunosuppressants.

RESULTS

Grafts with long sutures were rejected in 7.3 +/- 1.2 days, whereas those with short sutures were rejected after 11.8 +/- 1.0 days (P < 0.001). Similarly, long sutures induced more pronounced corneal neovascularization (P < 0.001). Although groups of recipients with long sutures all tested immunosuppressants significantly (P < 0.01-0.001) prolonged corneal graft survival, none of them showed a comparable efficacy in groups of recipients with short sutures.

CONCLUSIONS

This study showed that suturing technique significantly affects the outcome of corneal concordant xenograft transplantation, influences the effectiveness of immunosuppressive regimens, and therefore must be taken into account when evaluating their efficacy.

Met-RANTES reduces endothelial progenitor cell homing to activated (glomerular) endothelium in vitro and in vivo

The chemokine RANTES (regulated upon activation normal T-cell expressed and secreted) is involved in the formation of an inflammatory infiltrate during glomerulonephritis. However, RANTES receptor inhibition, although reducing glomerular leukocyte infiltration, can also increase damage. We hypothesized that RANTES does not only promote the influx and activation of inflammatory leukocytes but also mediates glomerular microvascular repair by stimulating the homing of bone marrow (BM)-derived endothelial progenitor cells. To investigate the role of RANTES in the participation of BM-derived cells in glomerular vascular repair, we used a rat BM transplantation model in combination with reversible anti-Thy-1.1 glomerulonephritis. Twenty-four hours after the induction of glomerulonephritis, BM-transplanted rats were treated for 7 days with either the RANTES receptor antagonist Met-RANTES or saline. The participation of BM-derived endothelial cells in glomerular repair, glomerular monocyte infiltration, and proteinuria was evaluated at days 7 and 28. Furthermore, we used an in vitro perfusion chamber assay to study the role of RANTES receptors in shear-resistant adhesion of the CD34+ stem cells to activated endothelium under flow. In our reversible glomerulonephritis model, RANTES receptor inhibition specifically reduced the participation of BM-derived cells in glomerular vascular repair by more than 40% at day 7 without impairing monocyte influx. However, no obvious change in recovery from proteinuria or morphological damage was observed. Blockade of RANTES receptors on CD34+ cells in vitro partially inhibited platelet-enhanced, shear-resistant firm adhesion of the CD34+ cells to activated endothelium. In conclusion, our data suggest that RANTES is involved in the homing and participation of BM-derived endothelial cells in glomerular repair.