Identification of a four immune-related genes signature based on an immunogenomic landscape analysis of clear cell renal cell carcinoma.

Renal clear cell carcinoma (ccRCC) is the most common type of renal cell carcinoma, which has strong immunogenicity. A comprehensive study of the role of immune-related genes (IRGs) in ccRCC is of great significance in finding ccRCC treatment targets and improving patient prognosis. In this study, we comprehensively analyzed the expression of IRGs in ccRCC based on The Cancer Genome Atlas datasets. The mechanism of differentially expressed IRGs in ccRCC was analyzed by bioinformatics. In addition, Cox regression analysis was used to screen prognostic related IRGs from differentially expressed IRGs. We also identified a four IRGs signature consisting of four IRGs (CXCL2, SEMA3G, PDGFD, and UCN) through lasso regression and multivariate Cox regression analysis. Further analysis results showed that the four IRGs signature could effectively predict the prognosis of patients with ccRCC, and its predictive power is independent of other clinical factors. In addition, the correlation analysis of immune cell infiltration showed that this four IRGs signature could effectively reflect the level of immune cell infiltration of ccRCC. We also found that the expression of immune checkpoint genes CTLA-4, LAG3, and PD-1 in the high-risk group was higher than that in the low-risk group. Our research revealed the role of IRGs in ccRCC, and developed a four IRGs signature that could be used to evaluate the prognosis of patients with ccRCC, which will help to develop personalized treatment strategies for patients with ccRCC and improve their prognosis. In addition, these four IRGs may be effective therapeutic targets for ccRCC.

Targeting PDGF-mediated recruitment of pericytes blocks vascular mimicry and tumor growth.

Aggressive tumor cells can adopt an endothelial cell-like phenotype and contribute to the formation of a tumor vasculature, independent of tumor angiogenesis. This adoptive mechanism is referred to as vascular mimicry and it is associated with poor survival in cancer patients. To what extent tumor cells capable of vascular mimicry phenocopy the angiogenic cascade is still poorly explored. Here, we identify pericytes as important players in vascular mimicry. We found that pericytes are recruited by vascular mimicry-positive tumor cells in order to facilitate sprouting and to provide structural support of the vascular-like networks. The pericyte recruitment is mediated through platelet-derived growth factor (PDGF)-B. Consequently, preventing PDGF-B signaling by blocking the PDGF receptors with either the small tyrosine kinase inhibitor imatinib or blocking antibodies inhibits vascular mimicry and tumor growth. Collectively, the current study identifies an important role for pericytes in the formation of vascular-like structures by tumor cells. Moreover, the mechanism that controls the pericyte recruitment provides therapeutic opportunities for patients with aggressive vascular mimicry-positive cancer types. © 2018 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Cerebrospinal fluid biomarkers and HIV-associated neurocognitive disorders in HIV-infected individuals in Rakai, Uganda.

In the USA, increased cerebrospinal fluid (CSF) inflammatory cytokines have been observed in antiretroviral therapy (ART)-naive, HIV-seropositive individuals with HIV-associated neurocognitive disorder (HAND). We characterized the relationship between HAND and CSF biomarker expression in ART-naive, HIV-seropositive individuals in Rakai, Uganda. We analyzed CSF of 78 HIV-seropositive, ART-naive Ugandan adults for 17 cytokines and 20 neurodegenerative biomarkers via Luminex multiplex assay. These adults underwent neurocognitive assessment to determine their degree of HAND. We compared biomarker concentrations between high and low CD4 groups and across HAND classifications, adjusting for multiple comparisons. Individuals with CD4 <200 cells/µL (N = 38) had elevated levels of CSF Interleukin (IL)-2, IL-12, granulocyte-macrophage colony-stimulating factor (GM-CSF), TNF-α, matrix metalloproteinase (MMP)-1, MMP-7, and S100 calcium-binding protein B (S100B) and lower levels of amyloid ß42. Individuals with CD4 351-500 cells/µL (N = 40) had significantly higher CSF levels of interleukin (IL)-1ß, amyloid ß42, and soluble receptor for advanced glycation end products (sRAGE). Increasing levels of S100B, platelet-derived growth factor-AA (PDGF-AA), brain-derived neurotrophic factor (BDNF), and sRAGE were associated with decreased odds of mild neurocognitive disorder (n = 22) or HIV-associated dementia (n = 15) compared with normal function (n = 30) or asymptomatic neurocognitive impairment (n = 11). Increased levels of interferon (IFN)-γ were associated with increased odds of mild neurocognitive impairment or HIV-associated dementia relative to normal or asymptomatic neurocognitive impairment. Proinflammatory CSF cytokines, chemokines, and neurodegenerative biomarkers were present in increasing concentrations with advanced immunosuppression and may play a role in the development of HAND. The presence of select CNS biomarkers may also play a protective role in the development of HAND.

Cytokine Expression Pattern in Bone Marrow Microenvironment after Allogeneic Stem Cell Transplantation in Primary Myelofibrosis.

The only curative therapy for primary myelofibrosis (PMF) is allogeneic stem cell transplantation (ASCT). However, although we know that patients can benefit from ASCT, we do not know the extent of the changes of the expression profile of cytokines and matrix modulation factors. In this first systematic analysis, we evaluated the expression profile of 103 factors before and after transplantation to identify potential biomarkers. The expression of fibrosis-, inflammation-, and angiogenesis-associated genes was analyzed in a total of 52 bone marrow biopsies: PMF patients (n = 14) before and after ASCT and, for control purposes, post-ASCT multiple myeloma patients (n = 14) and non-neoplastic hematopoiesis (n = 10). In post-ASCT PMF cases, decreased expression of tissue inhibitor of metalloproteinases (TIMP) and platelet-derived growth factor alpha (PDGFA) correlated with bone marrow remodeling and hematological remission. Expression of several other matrix factors remained at high levels and may contribute to post-ASCT remodeling. This is the first systematic analysis of cytokine expression in post-ASCT PMF bone marrow that shows that normalization of bone marrow microenvironment is paralleled by decreased expression of TIMP and PDGFA.

Negative regulation of the hepatic fibrogenic response by suppressor of cytokine signaling 1.

Suppressor of cytokine signaling 1 (SOCS1) is an indispensable regulator of IFNγ signaling and has been implicated in the regulation of liver fibrosis. However, it is not known whether SOCS1 mediates its anti-fibrotic functions in the liver directly, or via modulating IFNγ, which has been implicated in attenuating hepatic fibrosis. Additionally, it is possible that SOCS1 controls liver fibrosis by regulating hepatic stellate cells (HSC), a key player in fibrogenic response. While the activation pathways of HSCs have been well characterized, the regulatory mechanisms are not yet clear. The goals of this study were to dissociate IFNγ-dependent and SOCS1-mediated regulation of hepatic fibrogenic response, and to elucidate the regulatory functions of SOCS1 in HSC activation. Liver fibrosis was induced in Socs1(-/-)Ifng(-/-) mice with dimethylnitrosamine or carbon tetrachloride. Ifng(-/-) and C57BL/6 mice served as controls. Following fibrogenic treatments, Socs1(-/-)Ifng(-/-) mice showed elevated serum ALT levels and increased liver fibrosis compared to Ifng(-/-) mice. The latter group showed higher ALT levels and fibrosis than C57BL/6 controls. The livers of SOCS1-deficient mice showed bridging fibrosis, which was associated with increased accumulation of myofibroblasts and abundant collagen deposition. SOCS1-deficient livers showed increased expression of genes coding for smooth muscle actin, collagen, and enzymes involved in remodeling the extracellular matrix, namely matrix metalloproteinases and tissue inhibitor of metalloproteinases. Primary HSCs from SOCS1-deficient mice showed increased proliferation in response to growth factors such as HGF, EGF and PDGF, and the fibrotic livers of SOCS1-deficient mice showed increased expression of the Pdgfb gene. Taken together, these data indicate that SOCS1 controls liver fibrosis independently of IFNγ and that part of this regulation may occur via regulating HSC proliferation and limiting growth factor availability.

Phosphoinositide 3-kinase δ regulates migration and invasion of synoviocytes in rheumatoid arthritis.

Cartilage destruction mediated by invasive fibroblast-like synoviocytes (FLS) plays a central role in pathogenesis of rheumatoid arthritis (RA). Increased cell migration and degradation of extracellular matrix are fundamental to these processes. The class I PI3Ks control cell survival, proliferation, and migration, which might be involved in cartilage damage in RA. PI3Kδ isoform was recently identified as a key regulator of FLS growth and survival, suggesting that it could contribute to synoviocyte aggressive behavior. Therefore, we assessed the role of PI3Kδ in RA synoviocyte migration and invasion. We observed that PI3Kδ inhibition or small interfering RNA knockdown decreased platelet-derived growth factor (PDGF)-mediated migration and invasion of FLS. We then showed that PI3Kδ regulates the organization of actin cytoskeleton and lamellipodium formation during PDGF stimulation. To gain insight into molecular mechanisms, we examined the effect of PI3Kδ inhibition on Rac1/PAK, FAK, and JNK activation. Our studies suggest that Rac1/PAK is key target of PDGF-mediated PI3Kδ signaling, whereas FAK and JNK are not involved. Thus, PI3Kδ contributes to multiple aspects of the pathogenic FLS behavior in RA. These observations, together with previous findings that PI3Kδ regulates FLS growth and survival, suggest that PI3Kδ inhibition could be chondroprotective in RA by modulating synoviocyte growth, migration, and invasion.

Elevated sL1-CAM levels in BALF and serum of IPF patients.

BACKGROUND AND OBJECTIVE: IPF is a form of interstitial pneumonia of unknown origin that has a poor prognosis for which current treatments are limited. Recent studies have shown that EMT plays a role in IPF and tumour metastasis. L1-CAM has also been linked to EMT during tumour development and tumour metastasis. Our aim was to determine prospectively the level of L1-CAM in IPF patients. METHODS: Forty consecutive Chinese patients (with IPF, 16; LC, 12; and CC, 12), but no apparent lung or other organ's diseases were enrolled. Soluble L1-CAM (sL1-CAM), TGF-ß1, PDGF, γ-INF levels in BALF and serum sL1-CAM were measured using ELISA. RESULTS: BALF sL1-CAM levels of IPF, LC and CC patients were 10.87 ± 0.88 ng/mL, 6.34 ± 0.67 ng/mL and 5.43 ± 0.65 ng/mL, respectively. BALF sL1-CAM concentration of IPF patients was significantly higher than that in LC and in CC patients. Besides, serum sL1-CAM levels in patients with IPF, LC and CC were 9.60 ± 1.41 ng/mL, 9.82 ± 0.72 ng/mL and 5.41 ± 1.07 ng/mL, respectively. The serum sL1-CAM levels in patients with IPF and LC were significantly higher than those in patients with CC (P < 0.001, respectively). CONCLUSIONS: The concentrations of sL1-CAM both in BALF and in serum of patients with IPF are markedly increased compared with controls. This indicates that L1-CAM might be involved in the pathogenesis of IPF as well as that of LC.

Platelet-derived growth factor-D modulates extracellular matrix homeostasis and remodeling through TIMP-1 induction and attenuation of MMP-2 and MMP-9 gelatinase activities.

Platelet-derived growth factor-D (PDGF-D) is a more recent recognized growth factor involved in the regulation of several cellular processes, including cell proliferation, transformation, invasion, and angiogenesis by binding to and activating its cognate receptor PDGFR-ß. After bile duct ligation or in the carbon tetrachloride-induced hepatic fibrosis model, PDGF-D showed upregulation comparable to PDGF-B. Moreover, adenoviral PDGF-D gene transfer induced hepatic stellate cell proliferation and liver fibrosis. We here investigated the molecular mechanism of PDGF-D involvement in liver fibrogenesis. Therefore, the GRX mouse cell line was stimulated with PDGF-D and evaluated for fibrotic markers and PDGF-D signaling pathways in comparison to the other PDGF isoforms. We found that PDGF-D failed to enhance Col I and α-smooth muscle actin (α-SMA) production but has capacity to upregulate expression of the tissue inhibitor of metalloprotease 1 (TIMP-1) resulting in attenuation of MMP-2 and MMP-9 gelatinase activity as indicated by gelatinase zymography. This phenomenon was restored through application of a PDGF-D neutralizing antibody. Unexpectedly, PDGF-D incubation decreased both PDGFR-α and -ß in mRNA and protein levels, and PDGF-D phosphorylated typrosines specific for PDGFR-α and -ß. We conclude that PDGF-D intensifies fibrogenesis by interfering with the fibrolytic activity of the TIMP-1/MMP system and that PDGF-D signaling is mediated through both PDGF-α and -ß receptors.

Macrophages are the dominant effector cells responsible for IgG-mediated passive systemic anaphylaxis challenged by natural protein antigen in BALB/c and C57BL/6 mice.

IgG-induced passive systemic anaphylaxis (PSA), a serious adverse effect of passive immune therapy using therapeutic monoclonal antibodies, has been greatly emphasized. However, controversy exists regarding the type of effector cells involved in IgG-induced anaphylaxis as a result of the induction of PSA by different IgG subtypes or the use of mice with varying genetic backgrounds. To clarify the effector cells for PSA, the PSA model with serious hypothermia was established by IgG monoclonal antibody (mAb) against natural protein or complete antigen, not hapten conjugate, in BALB/c and C57BL/6 mice. The results indicated that PSA could be remarkably inhibited by the depletion of macrophages but not by the depletion of whole leukocytes, basophils, neutrophils or monocytes. We further confirmed that macrophages are indispensable for the PSA induced by all six IgG-natural antigen complexes in both strains of mice. Additionally, platelet-activating factor (PAF) was found to be the major effector mediator for IgG-induced anaphylaxis. Moreover, gene knock-out of the third component of complement (C3) did not affect PSA-related hypothermia in C57BL/6 mice. These results indicate that macrophages and PAF act as dominant effector cells and mediator molecules, respectively, and are indispensable components in the induction of IgG-mediated PSA induced by IgG mAb and natural protein antigen. Based on the above results, we hypothesize that inconsistencies in effector cells for PSA may be associated with different features of the mAb-antigen system that might affect the magnitude of FcγRs cross-linking on effector cells.

Platelet-derived growth factor C promotes revascularization in ischemic limbs of diabetic mice.

BACKGROUND: Platelet-derived growth factor C (PDGF-C) has been reported to promote angiogenesis independently of vascular endothelial growth factor (VEGF), although its significance in postnatal angiogenesis in vivo remains poorly understood. VEGF has been employed as a major molecular tool to induce therapeutic angiogenesis. However, VEGF therapy is not very effective in models of cardiovascular diseases associated with diabetes, and the mechanisms of this phenomenon still remain to be elucidated. METHODS: We used a murine model of hind limb ischemia and of streptozotocin-induced diabetes. RESULTS: Expression of PDGF-C and its receptor PDGFR-α were markedly upregulated in ischemic limbs. Treatment with a neutralizing antibody against PDGF-C significantly impaired blood flow recovery and neovascularization after ischemia almost to the same extent as a VEGF-neutralizing antibody. Mice deficient in PDGF-C exhibited reduced blood flow recovery after ischemia compared with wild-type mice, confirming a strong proangiogenic activity of PDGF-C. Next, we injected an expression vector encoding PDGF-C into ischemic limbs. Blood flow recovery and neovascularization after ischemia were significantly improved in the groups treated with PDGF-C compared with controls. Attenuation of angiogenic responses to ischemia has been reported in patients with diabetes even after VEGF treatment, although a precise mechanism remains unknown. We hypothesized that PDGF-C might relate to the impaired angiogenesis of diabetes. We tested this hypothesis by inducing diabetes by intraperitoneal injection of streptozotocin. Expression levels of PDGF-C at baseline and after ischemia were significantly lower in limb tissues of diabetic mice than in those of control mice, whereas expression levels of other members of the PDGF family and VEGF were not changed or were even higher in diabetic mice. Introduction of VEGF complementary DNA expression plasmid vector into ischemic limbs did not improve blood flow recovery. However, these changes were effectively reversed by additional introduction of the PDGF-C complementary DNA plasmid vector. CONCLUSIONS: These results indicate that downregulation of PDGF-C expression in limb tissues of diabetic mice contributes to impaired angiogenesis and suggest that introduction of PDGF-C might be a novel strategy for therapeutic angiogenesis, especially in the diabetic state. CLINICAL RELEVANCE: Angiogenesis and arteriogenesis after ischemia are attenuated in most diabetic patients, although the precise mechanisms remain unclear. Platelet-derived growth factors (PDGFs) have a variety of functions on many cell types, and PDGF-C stimulates angiogenesis and revascularizes ischemic tissues. This study indicates the role for PDGF-C as a critical regulator of impaired angiogenesis of diabetes and suggests that PDGF-C might be a novel target for the treatment of ischemic cardiovascular diseases in diabetes.

Mechanisms of persistent atrial fibrillation.

PURPOSE OF REVIEW: Atrial fibrillation is the most common sustained arrhythmia, but its mechanisms are poorly understood. In particular, little is known about the factors that contribute to the establishment of persistent or permanent atrial fibrillation. This review addresses possible common signaling pathways that might promote both structural and electrical remodeling of the atria, thus contributing to atrial fibrillation perpetuation. RECENT FINDINGS: Sustained atrial fibrillation may trigger an inflammatory response leading to activation of myofibroblasts and to the release of cytokines such as transforming growth factor-ß and platelet-derived growth factor, as well as profibrotic proteins such as galectin-3. Activation of signaling cascades involving such proteins is critical for the development of fibrosis and may also lead to ion channel dysfunction, which, along with myocyte apoptosis and extracellular matrix generation and turnover, likely contributes to both electrical and structural remodeling and predisposes to atrial fibrillation. SUMMARY: Identifying upstream strategies targeting molecular pathways that are common to fibrosis and electrical remodeling leading to atrial fibrillation perpetuation is highly desirable. This would facilitate finding new target genes with pleiotropic effects on the expression of ion channel proteins in myocytes and profibrotic molecules in nonmyocyte cells that are important for pathologic remodeling, which could become an important goal in persistent atrial fibrillation therapy.

Nanomechanical recognition of prognostic biomarker suPAR with DVD-ROM optical technology.

In this work the use of a high-throughput nanomechanical detection system based on a DVD-ROM optical drive and cantilever sensors is presented for the detection of urokinase plasminogen activator receptor inflammatory biomarker (uPAR). Several large scale studies have linked elevated levels of soluble uPAR (suPAR) to infectious diseases, such as HIV, and certain types of cancer. Using hundreds of cantilevers and a DVD-based platform, cantilever deflection response from antibody-antigen recognition is investigated as a function of suPAR concentration. The goal is to provide a cheap and portable detection platform which can carry valuable prognostic information. In order to optimize the cantilever response the antibody immobilization and unspecific binding are initially characterized using quartz crystal microbalance technology. Also, the choice of antibody is explored in order to generate the largest surface stress on the cantilevers, thus increasing the signal. Using optimized experimental conditions the lowest detectable suPAR concentration is currently around 5 nM. The results reveal promising research strategies for the implementation of specific biochemical assays in a portable and high-throughput microsensor-based detection platform.

PDGF-CC blockade inhibits pathological angiogenesis by acting on multiple cellular and molecular targets.

The importance of identifying VEGF-independent pathways in pathological angiogenesis is increasingly recognized as a result of the emerging drug resistance to anti-VEGF therapies. PDGF-CC is the third member of the PDGF family discovered after more than two decades of studies on PDGF-AA and PDGF-BB. The biological function of PDGF-CC and the underlying cellular and molecular mechanisms remain largely unexplored. Here, using different animal models, we report that PDGF-CC inhibition by neutralizing antibody, shRNA, or genetic deletion suppressed both choroidal and retinal neovascularization. Importantly, we revealed that PDGF-CC targeting acted not only on multiple cell types important for pathological angiogenesis, such as vascular mural and endothelial cells, macrophages, choroidal fibroblasts and retinal pigment epithelial cells, but also on the expression of other important angiogenic genes, such as PDGF-BB and PDGF receptors. At a molecular level, we found that PDGF-CC regulated glycogen synthase kinase (GSK)-3beta phosphorylation and expression both in vitro and in vivo. Activation of GSK3beta impaired PDGF-CC-induced angiogenesis, and inhibition of GSK3beta abolished the antiangiogenic effect of PDGF-CC blockade. Thus, we identified PDGF-CC as an important candidate target gene for antiangiogenic therapy, and PDGF-CC inhibition may be of therapeutic value in treating neovascular diseases.

Normal ageing is associated with an increase in Th2 cells, MCP-1 (CCL1) and RANTES (CCL5), with differences in sCD40L and PDGF-AA between sexes.

We have observed T helper type 2 (Th2) polarization of systemic immunity in patients with metastatic malignant melanoma. We hypothesized that similar changes in systemic immunity occur with ageing and may be permissive for the development of melanoma. We analysed the peripheral blood of 389 healthy blood donors. All subjects were profiled for peripheral blood T cell and B cell subsets, and 58 of these subjects were profiled for antigen-specific cytotoxic T cell subsets [cytomegalovirus (CMV), influenza and melanoma antigen recognized by T cells 1 (MART-1)]. Ninety-five separate healthy subjects underwent profiling of 42 plasma cytokines. Ageing was associated positively with CD4(+) CD294(+) Th2 cells, and associated negatively with CD3(+) T cells, cytotoxic T cells and T helper cells. Ageing was also associated negatively with CMV-, influenza- and MART-1-specific naive and CD8(+) T cells. There were significant increases in plasma monocyte chemotactic protein 1 (MCP-1) (CCL1) and regulated upon activation normal T cell expressed and secreted (RANTES) (CCL5) with age. We observed differences in cytokine profiles between males and females; specifically, women had higher levels of sCD40L and PDGF-AA. In summary, we demonstrated in healthy blood donors that ageing was associated with an increase in cellular Th2 bias and a decline in total numbers of T cells. Additionally, there was an increase in MCP-1 and RANTES with ageing. Women had higher levels of sCD40L and PDGF-AA than men.

HIF-1α signaling by airway epithelial cell K-α1-tubulin: role in fibrosis and chronic rejection of human lung allografts.

Long term survival of the human lung allografts are hindered by chronic rejection, manifested clinically as bronchiolitis obliterans syndrome (BOS). We previously demonstrated significant correlation between the development of antibodies (Abs) to K-α1-tubulin (Kα1T) and BOS. In this study, we investigated the molecular basis for fibrinogenesis mediated by ligation of Kα1T expressed on airway epithelial cells by its specific Abs. Using RT-PCR we demonstrate that normal human bronchial epithelial (NHBE) cells upon ligation of Kα1T with specific Abs caused upregulation of pro-fibrotic growth factors. Western blot analysis of NHBE incubated with Kα1T Abs increased hypoxia inducible factor (HIF-1α). Kα1T Ab-mediated growth factor expression is dependent on HIF-1α as inhibition of HIF-1α returned fibrotic growth factor expression to basal levels. In conclusion, we propose that HIF-1α -mediated upregulation of fibrogenic growth factors induced by ligation of Kα1T Abs is critical for development of fibrosis leading to chronic rejection of lung allograft.

Role of cytokines in lavage or drainage fluid after hemithyroidectomy in wound healing: involvement of histamine in the acceleration and delay of wound healing.

Wound healing is a sophisticated biologic process. In the case of hemithyroidectomy, the operation time is relatively short with small tissue damage and without skin excision, and bacterial contamination before, during, and after the operation is uncommon. Here, we explored which cytokine(s) affected the rates of healing of skin wounds after hemithyroidectomy of 29 patients. We assessed the amounts of cytokines (e.g., interleukin-6, platelet-derived growth factor, basic fibroblast growth factor, vascular endothelial growth factor, and tumor necrosis factor-α) in either the preoperative or postoperative lavage fluids, or in the drainage fluids on postoperative days (PODs) 1-8. All of these cytokines showed a similar pattern; after reaching a peak on POD1, the production fell sharply on POD2-8, revealing that wound healing commenced on POD1. The rates of wound healing were inversely related to the levels of histamine in six patients (i.e., those with the three largest and those with the three smallest total volumes of drainage fluid on POD1): high (or low) levels of histamine in the postoperative lavage fluids with low (or high) levels in the drainage fluids on POD1 caused earlier (or the delay of) wound healing, suggesting involvement of histamine in the acceleration and delay of wound healing.

Platelet-derived growth factor-producing CD4+ Foxp3+ regulatory T lymphocytes promote lung fibrosis.

RATIONALE: There is evidence that CD4(+) effector T lymphocytes (T eff) participate in the development of lung fibrosis, but the role of their CD4(+) regulatory T-cell (T reg) counterparts remains to be determined. OBJECTIVES: To elucidate the contribution of T reg cells in a mouse model of lung fibrosis induced by silica (SiO(2)) particles. METHODS: Lung T reg and T eff cells purified from SiO(2)-treated Foxp3-GFP transgenic mice were cocultured with naive lung fibroblasts or transferred to the lungs of healthy mice. DEREG mice, which express the diphtheria toxin receptor under the control of the foxp3 gene, were used to deplete T reg cells during fibrogenesis. MEASUREMENTS AND MAIN RESULTS: CD4(+) Foxp3(+) T reg cells were persistently recruited in the lungs in response to SiO(2). T reg accumulation paralleled the establishment of pulmonary immunosuppression and fibrosis. T reg cells highly expressed platelet-derived growth factor (PDGF)-B via a TGF-ß autocrine signaling pathway, directly stimulated fibroblast proliferation in vitro, and increased lung collagen deposition upon transfer in the lung of naive mice. The direct profibrotic effects of T reg cells were abolished by the inhibitor of the PDGF-B/TGF-ß signaling pathway, imatinib mesylate. Neutralization of T reg-immunosuppressive activity resulted in enhanced accumulation of T eff cells and IL-4-driven pulmonary fibrogenesis, further demonstrating that T reg cells control T eff cell functions during inflammatory fibrosis. CONCLUSIONS: Our study indicates that T reg cells contribute to lung fibrosis by stimulating fibroblasts through the secretion of PDGF-B in noninflammatory conditions and regulate detrimental T eff cell activities during inflammation-related fibrosis.

Effect of cocaine on human immunodeficiency virus-mediated pulmonary endothelial and smooth muscle dysfunction.

Human immunodeficiency virus (HIV)-associated pulmonary arterial hypertension (PAH) is a devastating, noninfectious complication of acquired immune deficiency syndrome, and the majority of HIV-PAH cases occur in individuals with a history of intravenous drug use (IVDU). However, although HIV-1 and IVDU have been associated with PAH independently or in combination, the pathogenesis of the disproportionate presence of HIV-PAH in association with IVDU has yet to be characterized. The objective of this study was to obtain a better understanding of the interactions between HIV-1 and cocaine to help uncover the mechanism(s) of the development of HIV-PAH. We observed that exposure of HIV-infected macrophages or HIV-Trans-Activator of Transcription (Tat)-treated pulmonary endothelial cells to cocaine enhanced the expression of platelet-derived growth factor (PDGF)-BB. Simultaneous treatment with Tat and cocaine, on the other hand, exacerbated both the disruption of tight junction proteins (TJPs), with enhanced permeability in pulmonary endothelial cells, and the proliferation of pulmonary smooth muscle cells (pSMCs) compared with either treatment alone. Histological examination of HIV plus IVDU human lung sections showed signs of early pulmonary arteriopathy, severe down-modulation of TJPs, and increased expression of PDGF-BB compared with the lung sections from individuals who are infected with HIV and without history of IVDU. Interestingly, blocking of PDGF receptor signaling with the receptor antagonist or small interfering RNA has been shown to inhibit the increase in proliferation of pSMCs on Tat and cocaine exposure. Our results, therefore, support an additive effect of cocaine to HIV infection in the development of pulmonary arteriopathy through enhancement of endothelial dysfunction and proliferation of pSMCs, while also suggesting PDGF-PDGF receptor axis as a potential target for use in clinical intervention.

Prospective, randomized, multi-center feasibility trial of rhPDGF-BB versus autologous bone graft in a foot and ankle fusion model.

BACKGROUND: The increased morbidity and surgical time associated with harvesting autologous bone graft (ABG) have encouraged surgeons to develop synthetic orthobiologic alternatives. The recombinant form of platelet-derived growth factor (rhPDGF-BB), an angiogenic, mitogenic, and chemotactic cytokine, has been shown to significantly enhance bone formation in human periodontal osseous defects when combined with a tricalcium phosphate carrier (ß-TCP). The purpose of this prospective, controlled, randomized, multi-center feasibility clinical trial was to compare the safety and efficacy of this biosynthetic bone graft substitute (Augment™ Bone Graft) to ABG during ankle and hindfoot fusion. MATERIALS AND METHODS: Twenty adult subjects requiring ankle or hindfoot fusion from three U.S. centers were enrolled and randomized in a 2:1 ratio to receive Augment™ or ABG, respectively. Surgical approach and fixation techniques were standardized, and minimum followup was 9 months. The primary endpoint was radiographic osseous union, evaluated by a blinded independent radiologist. Secondary endpoints included assessment of clinical success, union rate by serial computed tomography (CT) examination, time to full weightbearing, AOFAS Ankle-Hindfoot Score (AOFAS), Foot Function Index (FFI), Short Form-12 (SF-12), and Visual Analog pain assessment Scale (Pain VAS). RESULTS: At 36 weeks, 77% (10/13) of the Augment™ and 50% (3/6) of the ABG patients were fused based on radiographic criteria. There were two nonunions in the Augment™ group (9%, 2/14). Healing rates based on 12 week CT scanning (50% osseous bridging) were 69% (9/13) in the Augment™ and 60% (3/5) in the ABG groups, respectively. All functional outcome measures (FFI, AOFAS, SF-12), as well as the VAS pain scores, improved in both groups over time. Surgical procedure times lasted an average 26 minutes longer for the ABG as compared to the Augment™ populations. There were no device related serious adverse events in this study. CONCLUSION: Based on the available data, the rate of radiographic union, time to full weightbearing, and outcomes scores between the Augment™ and ABG subjects appear comparable. Augment™ may represent a safe and efficacious treatment alternative to ABG during foot and ankle arthrodesis.

Inhibition of mesangial cell proliferation and matrix expansion in glomerulonephritis in the rat by antibody to platelet-derived growth factor.

Platelet-derived growth factor (PDGF), a potent mitogen for mesenchymal cells in culture, is expressed in vivo in a variety of inflammatory conditions associated with cell proliferation, including atherosclerosis, wound repair, pulmonary fibrosis, and glomerulonephritis. However, it is not known if PDGF mediates the fibroproliferative responses that characterize these inflammatory disorders. We administered neutralizing anti-PDGF IgG or control IgG to rats with mesangial proliferative nephritis. Inhibition of PDGF resulted in a significant reduction in mesangial cell proliferation, and largely prevented the increased deposition of extracellular matrix associated with the disease. This suggests that PDGF may have a central role in proliferative glomerular disease.