Transforming growth factor-beta in human platelets. Identification of a major storage site, purification, and characterization

Recombinant Human ADAMTS13 Treatment Improves Myocardial Remodeling and Functionality After Pressure Overload Injury in Mice

Background

A disintegrin‐like metalloproteinase with thrombospondin motif type 1 member 13 (ADAMTS13), the von Willebrand factor–cleaving enzyme, decreases leukocyte and platelet recruitment and, thus, reduces thrombosis and inflammation. Recombinant human ADAMTS13 (rhADAMTS13) is a novel drug candidate for ischemia/reperfusion injury and has shown short‐term benefits in mouse models of myocardial injury, but long‐term outcome has not been investigated.

Methods and Results

We evaluated the impact of rhADAMTS13 on cardiac remodeling, scarring, and contractile function, under chronic left ventricular pressure overload. The role of von Willebrand factor and the effect of rhADAMTS13 treatment were studied. This model of heart failure, based on ascending aortic constriction, produces a coronary inflammatory response and microvascular dysfunction, resulting in fibrotic remodeling and cardiac failure. Mice were treated with either rhADAMTS13 or vehicle and assessed for coronary vascular inflammation and ventricular function at several postsurgical time points, as well as for cardiac fibrosis after 4 weeks. Early upon induction of pressure overload under rhADAMTS13 treatment, we detected less endothelial‐lumen–associated von Willebrand factor, fewer platelet aggregates, and decreased activated transforming growth factor‐β1 levels than in vehicle‐treated mice. We observed significant preservation of cardiac function and decrease in fibrotic remodeling as a result of rhADAMTS13 administration.

Conclusions

Herein, we show that rhADAMTS13 decreases coronary vascular dysfunction and improves cardiac remodeling after left ventricular pressure overload in mice. We propose that this effect may, at least in part, be the result of decreased von Willebrand factor–mediated recruitment of platelets, a major source of the activated profibrotic cytokine transforming growth factor‐β1. Our study further supports the therapeutic potential of rhADAMTS13 for conditions characterized by inflammatory cardiac damage that results in fibrosis.

SMAD4-independent activation of TGF-β signaling by MUC1 in a human pancreatic cancer cell line

Pancreatic Ductal Adenocarcinoma (PDA) has a mortality rate that nearly matches its incidence rate. Transforming Growth Factor Beta (TGF-β) is a cytokine with a dual role in tumor development switching from a tumor suppressor to a tumor promoter. There is limited knowledge of how TGF-β function switches during tumorigenesis. Mucin 1 (MUC1) is an aberrantly glycosylated, membrane-bound, glycoprotein that is overexpressed in >80% of PDA cases and is associated with poor prognosis. In PDA, MUC1 promotes tumor progression and metastasis via signaling through its cytoplasmic tail (MUC1-CT) and interacting with other oncogenic signaling molecules. We hypothesize that high levels of MUC1 in PDA may be partly responsible for the TGF-β functional switch during oncogenesis. We report that overexpression of MUC1 in BxPC3 human PDA cells (BxPC3.MUC1) enhances the induction of epithelial to mesenchymal transition leading to increased invasiveness in response to exogenous TGF-β1. Simultaneously, these cells resist TGF-β induced apoptosis by downregulating levels of cleaved caspases. We show that mutating the tyrosines in MUC1-CT to phenylalanine reverses the TGF-β induced invasiveness. This suggests that the tyrosine residues in MUC1-CT are required for TGF-β induced invasion. Some of these tyrosines are phosphorylated by the tyrosine kinase c-Src. Thus, treatment of BxPC3.MUC1 cells with a c-Src inhibitor (PP2) significantly reduces TGF-β induced invasiveness. Similar observations were confirmed in the Chinese hamster ovarian (CHO) cell line. Data strongly suggests that MUC1 may regulate TGF-β function in PDA cells and thus have potential clinical relevance in the use of TGF-β inhibitors in clinical trials.

Toward the clinical use of circulating biomarkers predictive of bone union

Current methods for diagnosis of bone healing after treatment of trauma injuries rely on clinical findings and the use of imaging methodologies that provide conclusive results but only at mid/long-term post-intervention. In this Perspective we present and discuss incipient evidence on biomarkers that may serve for monitoring the progression of bone healing as well as predicting eventual nonunion outcomes.

Small but mighty: Platelets as central effectors of host defense

Platelets actively participate in inflammatory processes and drive diseases such as atherosclerosis, rheumatoid arthritis and cancer metastasis. However, platelets also have anti-inflammatory and anti-infective properties, which have received less consideration in the past. In this review, we highlight recent findings on the role of platelets in host defense and describe regulatory pathways modulating immuneresponses. Furthermore, we discuss the role of platelets for the resolution of inflammation and tissue repair. These conceptual changes contribute to our understanding of platelet biology in disease.

Critical role of CREBH-mediated induction of transforming growth factor β2 by hepatitis C virus infection in fibrogenic responses in hepatic stellate cells

Mechanisms of hepatic fibrogenesis induced by hepatitis C virus (HCV), one of the leading causes of liver fibrosis, are not fully understood. We studied transcriptional up-regulation of transforming growth factor β (TGF-β), especially TGF-β2, which is mediated by activation of liver-enriched transcription factor cAMP-responsive element-binding protein, hepatocyte specific (CREBH) triggered by HCV infection and its functional significance for induction of profibrogenic phenotypes by interaction of HCV-infected cells with hepatic stellate cells (HSCs). Compared to TGF-β1, expression of TGF-β2 mRNA was induced faster and to a higher level upon HCV infection. Serum TGF-β2 levels in hepatitis C patients were higher compared to those in healthy individuals and were positively correlated with hepatic fibrosis stages F0-F2. TGF-β2 promoter activity was decreased and increased, respectively, by silencing and overexpression of CREBH. CREBH recognition sites were identified in the TGF-β2 promoter. CREBH binding to the promoter and its increase in cells expressing HCV Core-NS2 were shown by gel mobility shift and chromatin immunoprecipitation, respectively. The active form of CREBH was detectable in HCV-infected chimeric mice with human livers and cells expressing HCV proteins. Involvement of CREBH in HCV-induced fibrogenic response was further demonstrated in the CREBH null-mutant mouse model. Fibrogenic phenotypes were assessed using co-cultures of HCV-infected cells and HSCs. Expressions of fibrogenic factors and TGF-β1 increasing in the co-cultures was prevented by TGF-β2- or CREBH silencing.

CONCLUSION

CREBH was identified as a key positive regulator of TGF-β2 transcription in HCV-infected cells. TGF-β2 released from infected cells potentially contributes to cross-induction of TGF-β in an autocrine manner through its own signaling pathway, leading to an increase in fibrogenic responses in adjacent HSCs. (Hepatology 2017;66:1430-1443).

Platelet derived TGF-β promotes cervical carcinoma cell growth by suppressing KLF6 expression

Platelets in the primary tumor microenvironment play crucial roles in regulating tumor growth, metastasis, and angiogenesis, but the underlying mechanisms are unclear. Here, we show that platelet releasates exhibited a proliferative effect on HeLa cells, and this effect correlated with a reduction of KLF6 expression. After incubation with either washed human platelets or collagen-related peptide (CRP) activated platelet releasates, expression of KLF6 in the HeLa cervical tumor cell line was markedly reduced. However, no significant difference was observed between control HeLa cells and HeLa cells incubated with resuspended activated platelet pellet. Moreover, the platelets’ promoting effect on HeLa cell growth was significantly abolished in KLF6 silenced HeLa cells. In addition, blocking TGF-β signaling with SB431542, a TGF-β receptor inhibitor, also counteracted the effect of platelets on proliferation and KLF6 expression in HeLa cells. From these findings, we conclude that platelet derived TGF-β promotes proliferation of HeLa cells by decreasing the expression of KLF6. The discovery that KLF6 is a key target of platelet-derived TGF-β signaling in HeLa cells identifies a potential new therapeutic target for the prevention and treatment of cervical carcinoma.

Targeting Platelets for the Treatment of Cancer

The majority of cancer-associated mortality results from the ability of tumour cells to metastasise leading to multifunctional organ failure and death. Disseminated tumour cells in the blood circulation are faced with major challenges such as rheological shear stresses and cell-mediated cytotoxicity mediated by natural killer cells. Nevertheless, circulating tumour cells with metastatic ability appear equipped to exploit host cells to aid their survival. Despite the long interest in targeting tumour-associated host cells such as platelets for cancer treatment, the clinical benefit of this strategy is still under question. In this review, we provide a summary of the latest mechanistic and clinical evidence to evaluate the validity of targeting platelets in cancer.

Optimisation of a double-centrifugation method for preparation of canine platelet-rich plasma

Background

Platelet-rich plasma (PRP) has been expected for regenerative medicine because of its growth factors. However, there is considerable variability in the recovery and yield of platelets and the concentration of growth factors in PRP preparations. The aim of this study was to identify optimal relative centrifugal force and spin time for the preparation of PRP from canine blood using a double-centrifugation tube method.

Methods

Whole blood samples were collected in citrate blood collection tubes from 12 healthy beagles. For the first centrifugation step, 10 different run conditions were compared to determine which condition produced optimal recovery of platelets. Once the optimal condition was identified, platelet-containing plasma prepared using that condition was subjected to a second centrifugation to pellet platelets. For the second centrifugation, 12 different run conditions were compared to identify the centrifugal force and spin time to produce maximal pellet recovery and concentration increase. Growth factor levels were estimated by using ELISA to measure platelet-derived growth factor-BB (PDGF-BB) concentrations in optimised CaCl₂-activated platelet fractions.

Results

The highest platelet recovery rate and yield were obtained by first centrifuging whole blood at 1000 g for 5 min and then centrifuging the recovered platelet-enriched plasma at 1500 g for 15 min. This protocol recovered 80% of platelets from whole blood and increased platelet concentration six-fold and produced the highest concentration of PDGF-BB in activated fractions.

Conclusions

We have described an optimised double-centrifugation tube method for the preparation of PRP from canine blood. This optimised method does not require particularly expensive equipment or high technical ability and can readily be carried out in a veterinary clinical setting.

Electronic supplementary material

The online version of this article (doi:10.1186/s12917-017-1123-3) contains supplementary material, which is available to authorized users.

Atrophic Mandible Fractures: Are Bone Grafts Necessary? An Update

PURPOSE

The management of atrophic mandibular fractures poses a challenge because of anatomic variations and medical comorbidities associated with elderly patients. The purpose of this article is to review and update the literature regarding the management of atrophic mandible fractures using load-bearing reconstruction plates placed without bone grafts.

MATERIALS AND METHODS

We performed a review of the English-language literature looking for atrophic mandibular fractures with or without continuity defects and reconstruction without bone grafts. Included are 2 new patients from our institution who presented with fractures of their atrophic mandibles and had continuity defects and infections. Both patients underwent reconstruction with a combination of a reconstruction plate, recombinant human bone morphogenetic protein 2, and tricalcium phosphate. This study was approved as an "exempt study" by the Institutional Review Board at the University of Kentucky. This investigation observed the Declaration of Helsinki on medical protocol and ethics.

RESULTS

Currently, the standard of care to manage atrophic mandibular fractures with or without a continuity defect is a combination of a reconstruction plate plus autogenous bone graft. However, there is a need for an alternative option for patients with substantial comorbidities. Bone morphogenetic proteins, with or without additional substances, appear to be a choice. In our experience, successful healing occurred in patients with a combination of a reconstruction plate, recombinant human bone morphogenetic protein 2, and tricalcium phosphate.

CONCLUSIONS

Whereas primary reconstruction of atrophic mandibular fractures with reconstruction plates supplemented with autogenous bone graft is the standard of care, in selected cases in which multiple comorbidities may influence local and/or systemic outcomes, bone morphogenetic proteins and tricalcium phosphate can be used as a predictable alternative to autogenous grafts.

Platelet releasates promote the proliferation of hepatocellular carcinoma cells by suppressing the expression of KLF6

Platelets in the primary tumor microenvironment play crucial roles in the regulation of tumor progression, but the mechanisms underlying are poorly understood. Here, we report that platelet releasates exerted a proliferative effect on hepatocellular carcinoma (HCC) cells both in vitro and in vivo. This effect depended on a reduction of KLF6 expression in HCC cells. After incubation with either platelets or platelet granule contents, SMMC.7721 and HepG2 cells exhibited significant increases in proliferation and decreases in apoptosis. However, no effect was observed when incubating cancer cells with resuspended activated platelet pellet which exhausted of releasates. Platelet releasates also increased the population of HCC cells in the S and G2/M phases of the cell cycle and reduced the cell population in the G0/G1 phase. Moreover, knocking down KLF6 expression significantly diminished the platelet-mediated enhancement of HCC growth. In addition, blocking TGF-β signaling with the TGF-β receptor inhibitor SB431542 counteracted the effect of platelets on KLF6 expression and proliferation of HCC cells. Based on these findings, we conclude that platelet releasates, especially TGF-β, promote the proliferation of SMMC.7721 and HepG2 cells by decreasing expression of KLF6. This discovery identifies a potential new therapeutic target for the prevention and treatment of hepatocellular carcinoma.

Role of Platelet-Derived Tgfβ1 in the Progression of Ovarian Cancer

Purpose: Transforming growth factor β1 (Tgfβ1) plays an important role in cancer. Most of Tgfβ1 in plasma is from platelets; thus, we studied whether platelet Tgfβ1 has any role in the progression of ovarian cancer, and whether this role is limited to metastasis or also involves the growth of primary tumors.Experimental Design: We compared the growth of murine ovarian cancer cell-induced tumors in platelet-specific Tgfβ1-deficient mice and wild-type mice. Using resected tumor nodules, we studied the effect of platelet Tgfβ1 on neoangiogenesis and on platelet extravasation into tumors. To investigate the effect of Tgfβ1 at different stages of ovarian cancer, we reduced expression of Tgfβ1 receptor (its TgfβR1 component) in tumors at different time points after injection of cancer cells, and compared the final tumor size.Results: Lack of platelet Tgfβ1 in mice reduced tumor growth, neoangiogenesis, and platelet extravasation. Ovarian cancer tumors in platelet-specific Tgfβ1-deficient mice reached less than half of their size in wild-type littermates. Knockdown of TgfβR1 on cancer cells in the first 2 weeks after their injection reduced tumor growth, but was less effective if initiated after 3 weeks.Conclusions: We showed that platelet Tgfβ1 increased the growth of primary tumors in murine models of ovarian cancer. We also showed that inhibition of TgfβR1 is more effective in reducing the growth of ovarian cancer if initiated earlier. Our results supported a therapeutic benefit in preventing platelet activation, degranulation, and release of Tgfβ1 in ovarian cancer. Clin Cancer Res; 23(18); 5611-21. ©2017 AACR.

The role of platelets in autoimmunity, vasculopathy, and fibrosis: Implications for systemic sclerosis

INTRODUCTION

Systemic sclerosis (SSc) is an autoimmune disease characterized by vasculopathy, autoimmunity, and widespread dermal and visceral fibrosis. This article summarizes the current knowledge about the potential contribution of platelets in the disease process and the rationale of targeting platelets as an adjunct treatment for SSc.

METHODS

We performed an electronic search (Medline) using the keywords platelets, systemic sclerosis, autoimmunity, fibrosis, Raynaud, and pulmonary arterial hypertension.

RESULTS

The link that connects vasculopathy, autoimmunity, and fibrosis in SSc remains obscure. Experimental data suggest that platelets are not solely cell fragments regulating hemostasis but they have a pleiotropic role in several biologic processes including immune regulation, vasculopathy, fibrosis, and all key features of SSc. Platelets interplay with the impaired endothelium, can interact with immune cells, and they are storages of bioactive molecules involved in tissue injury and remodeling. The potential role of platelets in the pathogenesis of SSc is further supported by experimental data in animal models of SSc. Platelet-derived serotonin represents a novel target in SSc and serotonin blockade is currently being tested in clinical trials.

CONCLUSION

Platelets may be actively involved in the pathogenesis of SSc by activating immune responses and facilitating the fibrotic process. However, definite conclusions cannot be drawn until more data from both basic and clinical research are available.

Resveratrol suppresses pulmonary tumor metastasis by inhibiting platelet-mediated angiogenic responses

BACKGROUND

To explore the impact of Resveratrol (RSV) on the angiogenic potential of activated platelets and to elucidate the underlying mechanism.

METHODS

Vascular endothelial growth factor concentrations were measured by enzyme-linked immunosorbent assay. Capillary tube formation assay was used to examine the impact of RSV on the angiogenic potential of activated platelets. The levels of cyclic adenosine monophosphate and cyclic guanosine monophosphate (cGMP) in the supernatant were evaluated using corresponding enzyme-linked immunosorbent assay kits. Immunoblotting assays were used to determine the expression of vasodilator-stimulated phosphoprotein and Akt phosphorylation. A pulmonary metastasis experiment with male nude mice model was performed to test the effect of RSV on pulmonary metastasis and angiogenesis in vivo.

RESULTS

RSV inhibited platelets-mediated angiogenic responses induced by adenosine diphosphate (ADP)ADP through increased cGMP generation and cGMP-mediated vasodilator-stimulated phosphoprotein phosphorylation along with reduced intracellular Ca²⁺ mobilization. In addition, RSV attenuated the platelet secretion and angiogenic responses induced by A549 cells in vitro and suppressed A549 lung cancer metastasis and angiogenesis in nude mice.

CONCLUSIONS

RSV is a potential therapeutic drug for the prevention of tumor metastasis by interrupting the platelet-tumor cell amplification loop.

Platelets subvert T cell immunity against cancer via GARP-TGFβ axis

Cancer-associated thrombocytosis has long been linked to poor clinical outcome, but the underlying mechanism is enigmatic. We hypothesized that platelets promote malignancy and resistance to therapy by dampening host immunity. We show that genetic targeting of platelets enhances adoptive T cell therapy of cancer. An unbiased biochemical and structural biology approach established transforming growth factor β (TGFβ) and lactate as major platelet-derived soluble factors to obliterate CD4⁺ and CD8⁺ T cell functions. Moreover, we found that platelets are the dominant source of functional TGFβ systemically as well as in the tumor microenvironment through constitutive expression of the TGFβ-docking receptor glycoprotein A repetitions predominant (GARP) rather than secretion of TGFβ per se. Platelet-specific deletion of the GARP-encoding gene Lrrc32 blunted TGFβ activity at the tumor site and potentiated protective immunity against both melanoma and colon cancer. Last, this study shows that T cell therapy of cancer can be substantially improved by concurrent treatment with readily available antiplatelet agents. We conclude that platelets constrain T cell immunity through a GARP-TGFβ axis and suggest a combination of immunotherapy and platelet inhibitors as a therapeutic strategy against cancer.

Potential of extravasated platelet aggregation as a surrogate marker for overall survival in patients with advanced gastric cancer treated with preoperative docetaxel, cisplatin and S-1: a retrospective observational study

BACKGROUND

The theory of extravasated platelet aggregation in cancer lesions was recently introduced. We investigated the association of platelet aggregation in gastric cancer stroma with clinicopathological features, chemotherapeutic response, pathological response, and survival.

METHODS

The study comprised 78 patients with advanced gastric cancer who had undergone gastrectomy with or without combination of docetaxel, cisplatin and S-1 (DCS) as preoperative chemotherapy between 2005 and 2014. The patients were divided into two groups: patients who had received preoperative DCS therapy forming the p-DCS group and patients who had not received preoperative DCS therapy forming the control group. The 39 patients in the control group had received gastrectomy and postoperative chemotherapy of S-1 alone. Platelet aggregation in biopsy specimens before preoperative DCS therapy in the p-DCS group and at the time of diagnosis in the control group were evaluated using CD42b immunohistochemical staining.

RESULTS

Twenty-four patients in the p-DCS group and 19 in the control group were found to have platelet aggregation in their cancer stroma. Patients with histologically confirmed platelet aggregation had significantly higher rates of chemoresistance (58.3%) than those without platelet aggregation (20.0%) (P = 0.019). According to multivariate analysis, CD42b expression (odds ratio: 5.102, 95% confidence interval: 1.039-25.00, P = 0.045) was correlated with chemoresistance. CD42b expression and histological non-responder status were both significantly correlated with poor overall survival (OS) (P = 0.012, P = 0.016); however, RECIST was not correlated with OS. In the control group, CD42b expression was also significantly correlated with poor overall survival (OS) (P = 0.033). In the p-DCS group, according to multivariate analysis, male sex (hazard ratio: 0.281, 95% confidence interval: 0.093-0.846, P = 0.024) was correlated with good prognosis and CD42b expression (hazard ratio: 4.406, 95% confidence interval: 1.325-14.65, P = 0.016) with poor prognosis.

CONCLUSIONS

This study suggests that platelets in gastric cancer stroma may create a favorable microenvironment for chemoresistance. CD42b immunohistochemical staining of biopsy specimens is a promising candidate for being a prognostic marker in patients with gastric cancer.

Assessment of Th17/Treg cells and Th cytokines in an improved immune thrombocytopenia mouse model

OBJECTIVES

The improved passive immune thrombocytopenia (ITP) mouse model has been extensively utilized for the study of ITP. However, how closely this model matches the human inflammation state and immune background is unclear. Our study aimed to explore the profile of Th cytokines and Th17/Treg cells in the model.

METHODS

We induced the ITP mouse model by dose-escalation injection of MWReg30. The serum levels of cytokines (IFN-γ, IL-2, IL-4, IL-10, IL-17A, and TGF-β1) were measured by enzyme-linked immunosorbent assay and the frequency of Th17 and Treg cells was measured by flow cytometry. The mRNA expression of Foxp3 and RORrt was measured by real-time PCR.

RESULTS

The serum levels of cytokines IFN-γ, TGF-β1, IL-4, and IL-10 were significantly lower in ITP mice. The secretion of serum proinflammatory cytokines IL-2 and IL-17A and the percentage of Th17 cells showed no statistically significant increase. In ITP mice the frequency of Treg cells and mRNA expression of Foxp3 was significantly lower in splenocytes.

CONCLUSION

Our data suggest that the improved passive ITP mouse model does not mimic the autoimmune inflammatory process of human ITP. Compared with human ITP, this model has a similar change in frequency of Treg cells, which may directly or indirectly result from antibody-mediated platelet destruction due to attenuated release of TGF-β.

A critical role of platelet TGF-β release in podoplanin-mediated tumour invasion and metastasis

The tumour microenvironment is critical for various characteristics of tumour malignancies. Platelets, as part of the tumour microenvironment, are associated with metastasis formation via increasing the rate of tumour embolus formation in microvasculature. However, the mechanisms underlying the ability of tumour cells to acquire invasiveness and extravasate into target organs at the site of embolization remain unclear. In this study, we reported that platelet aggregation-inducing factor podoplanin expressed on tumour cell surfaces were found to not only promote the formation of tumour-platelet aggregates via interaction with platelets, but also induced the epithelial-mesenchymal transition (EMT) of tumour cells by enhancing transforming growth factor-β (TGF-β) release from platelets. In vitro and in vivo analyses revealed that podoplanin-mediated EMT resulted in increased invasiveness and extravasation of tumour cells. Treatment of mice with a TGF-β-neutralizing antibody statistically suppressed podoplanin-mediated distant metastasis in vivo, suggesting that podoplanin promoted haematogenous metastasis in part by releasing TGF-β from platelets that was essential for EMT of tumour cells. Therefore, our findings suggested that blocking the TGF-β signalling pathway might be a promising strategy for suppressing podoplanin-mediated haematogenous metastasis in vivo.

The role of the extracellular matrix in primary myelofibrosis

Primary myelofibrosis (PMF) is a myeloproliferative neoplasm that arises from clonal proliferation of hematopoietic stem cells and leads to progressive bone marrow (BM) fibrosis. While cellular mutations involved in the development of PMF have been heavily investigated, noteworthy is the important role the extracellular matrix (ECM) plays in the progression of BM fibrosis. This review surveys ECM proteins contributors of PMF, and highlights how better understanding of the control of the ECM within the BM niche may lead to combined therapeutic options in PMF.

Transforming growth factor-β1 functional polymorphisms in myeloablative sibling hematopoietic stem cell transplantation

Hematopoietic stem cell transplantation (HSCT) with sibling donors (s.d.) is a life-saving intervention for patients with hematological malignancies. Numerous genetic factors have a role in transplant outcome. Several functional polymorphisms have been identified in TGF-β1 gene, such as single-nucleotide polymorphism (SNP) at +29C>T within exon 1. Two hundred and forty five patient/donor pairs who underwent a s.d. HSCT in our centers were genotyped for this SNP. In the myeloablative cohort, +29CC donors were associated with an increase in severe chronic GvHD (32% vs 16%, hazard ratio (HR) 9.0, P=0.02). Regarding survival outcomes, +29CC patients developed higher non relapse mortality (NRM) (1-5 years CC 28-32% vs TC/TT 7-10%; HR 5.1, P=0.01). Recipients of +29TT donors experienced a higher relapse rate (1-5 years TT 37-51% vs TC 19-25% vs CC 13%-19%; HR 2.4, P=0.01) with a decreased overall survival (OS) (1-5 years TT 69-50% vs TC/CC 77-69%; HR 1.9, P=0.05). Similar to previous myeloablative unrelated donors HSCT results, we confirmed that +29CC patients had higher NRM. In addition we found that +29TT donors might be associated with a higher relapse rate and lower OS. These results should be confirmed in larger series. Identification of these SNPs will allow personalizing transplant conditioning and immunosuppressant regimens, as well as assisting in the choice of the most appropriate donor.

Cancer and Thrombosis: The Platelet Perspective

Platelets are critical to hemostatic and immunological function, and are key players in cancer progression, metastasis, and cancer-related thrombosis. Platelets interact with immune cells to stimulate anti-tumor responses and can be activated by immune cells and tumor cells. Platelet activation can lead to complex interactions between platelets and tumor cells. Platelets facilitate cancer progression and metastasis by: (1) forming aggregates with tumor cells; (2) inducing tumor growth, epithelial-mesenchymal transition, and invasion; (3) shielding circulating tumor cells from immune surveillance and killing; (4) facilitating tethering and arrest of circulating tumor cells; and (5) promoting angiogenesis and tumor cell establishment at distant sites. Tumor cell-activated platelets also predispose cancer patients to thrombotic events. Tumor cells and tumor-derived microparticles lead to thrombosis by secreting procoagulant factors, resulting in platelet activation and clotting. Platelets play a critical role in cancer progression and thrombosis, and markers of platelet-tumor cell interaction are candidates as biomarkers for cancer progression and thrombosis risk.

Application of platelet-rich plasma with stem cells in bone and periodontal tissue engineering

Presently, there is a high paucity of bone grafts in the United States and worldwide. Regenerating bone is of prime concern due to the current demand of bone grafts and the increasing number of diseases causing bone loss. Autogenous bone is the present gold standard of bone regeneration. However, disadvantages like donor site morbidity and its decreased availability limit its use. Even allografts and synthetic grafting materials have their own limitations. As certain specific stem cells can be directed to differentiate into an osteoblastic lineage in the presence of growth factors (GFs), it makes stem cells the ideal agents for bone regeneration. Furthermore, platelet-rich plasma (PRP), which can be easily isolated from whole blood, is often used for bone regeneration, wound healing and bone defect repair. When stem cells are combined with PRP in the presence of GFs, they are able to promote osteogenesis. This review provides in-depth knowledge regarding the use of stem cells and PRP in vitro, in vivo and their application in clinical studies in the future.

Platelets as immune-sensing cells

Publisher's Note: This article has a companion Point by Brass et al. Publisher's Note: Join in the discussion of these articles at Blood Advances Community Conversations.

Synergistic effects of overexpression of BMP‑2 and TGF‑β3 on osteogenic differentiation of bone marrow mesenchymal stem cells

Bone morphogenetic protein 2 (BMP-2) and transforming growth factor β (TGF-β) isoforms are important in advancing bone regeneration. The aim of the present study was to investigate the positive and reciprocal effect of TGF-β3, one of the three TGF-β isoforms, on BMP-2 in promoting osteogenic differentiation. Exogenous BMP-2 and TGF-β3 genes were separately, and in combination, overexpressed in rabbit bone marrow-derived mesenchymal stem cells (rBMSCs). Expression levels of BMP-2 and TGF-β3 were evaluated using reverse-transcription-polymerase chain reaction (RT-PCR) and Western blotting assays. Furthermore, the osteogenic differentiation capacities of BMSCs were assessed by measuring Alizarin Red S staining, an alkaline phosphatase activity assay, and quantification of the osteogenic-specific genes, Runt-related transcription factor 2 (Runx2) and Osterix (Osx). Using lentiviral-mediated transfection, robust co-transfection efficiency of >90% was achieved. RT-PCR and immunoblotting results indicated a marked elevated expression of BMP-2 and TGF-β3 in rBMSCs undergoing co-transfection, compared with transfection with BMP-2 or TGF-β3 alone, indicating that BMP-2 and TGF-β3 are synergistically expressed in rBMSCs. Furthermore, enhanced osteogenic differentiation was observed in rBMSCs co-transfected with BMP-2/TGF-β3. The present study successfully delivered BMP-2 together with TGF-β3 into rBMSCs with high efficiency for the first time. Furthermore, TGF-β3 overexpression was demonstrated to enhance the osteogenic efficacy of BMP-2 in rBMSCs, and vice versa. This provides a potential clinical therapeutic approach for regenerating the function of osseous tissue, and may present a promising strategy for bone defect healing.

Review of Osteosarcoma and Current Management

Osteosarcoma is the most common primary malignancy of bone in children and young adults. This tumor has a very heterogeneous genetic profile and lacks any consistent unifying event that leads to the pathogenesis of osteosarcoma. In this review, some of the important genetic events involved in osteosarcoma will be highlighted. Additionally, the clinical diagnosis of osteosarcoma will be discussed, as well as contemporary chemotherapeutic and surgical management of this tumor. Finally, the review will discuss some of the novel approaches to treating this disease.

Smad4 is required to inhibit osteoclastogenesis and maintain bone mass

Bone homeostasis is maintained as a delicate balance between bone-resorption and bone-formation, which are coupled to maintain appropriate bone mass. A critical question is how bone-resorption is terminated to allow bone-formation to occur. Here, we show that TGFβs inhibit osteoclastogenesis and maintain bone-mass through Smad4 activity in osteoclasts. We found that latent-TGFβ1 was activated by osteoclasts to inhibit osteoclastogenesis. Osteoclast-specific Smad4 conditional knockout mice (Smad4-cKO) exhibited significantly reduced bone-mass and elevated osteoclast formation relative to controls. TGFβ1-activation induced expression of Irf8 and Bcl6, both of which encode factors inhibiting osteoclastogenesis, by blocking their negative regulator, Prdm1, in osteoclasts in a Smad4-dependent manner. Reduced bone-mass and accelerated osteoclastogenesis seen in Smad4-cKO were abrogated by Prdm1 deletion. Administration of latent-TGFβ1-Fc to wild-type mice antagonized LPS-induced bone destruction in a model of activated osteoclast-mediated bone destruction. Thus, latent-TGFβ1-Fc could serve as a promising new therapeutic agent in bone diseases marked by excessive resorption.

Effect of the herbal mixture composed of Aloe Vera, Henna, Adiantum capillus-veneris, and Myrrha on wound healing in streptozotocin-induced diabetic rats

BACKGROUND

Wound healing is often impaired in diabetic animals and humans. Matrix metalloproteases act as pro-inflammatory agents in physiological wound healing pathways by stimulating cytokines including the interleukins, IL6, IL1A and IL1B, and the tumor necrosis factor and transforming growth factor beta1. Botanicals are traditionally used to assist healing of different types of wounds, because they produce fewer side effects. Our specific aim here was to develop a plant-based recipe supporting effective wound healing in diabetic animals.

METHODS

Plant materials from Adiantum capillus-veneris, Commiphora molmol, Aloe Vera, and henna were collected for this study, and oven-dried at 60 °C. The dried leaves and resins were then crumbled into a powder and mixed in equal parts with Vaseline as a preservative. This mixture was used as an ointment on wounds induced in 60 diabetic and non-diabetic rats that were divided into 6 subgroups receiving agent or control treatments. Necrotic tissue surrounding the wound was periodically removed during wound healing. RNA was extracted from the healing region of the wound at days 7, 14 and 21 for cDNA synthesis to monitor changes in Tgfb1, Mmp3, Mmp9, Il6 and Tnf α expression using real-time PCR.

RESULTS

The expression of the Mmp3, the Tnf α, and the Tgfb1 genes from wound tissue were significantly different (p < 0.05) between diabetic and non-diabetic (control) rats treated with the herbal mixture after 14 and 21 days. There was no significant difference (p > 0.05) of the Mmp9 gene expression in diabetic and non-diabetic rats treated only with Vaseline after 7, 14, and 21 days. But, the expression of the Mmp9 gene decreased significantly (p < 0.05) in diabetic rats after 14 days in comparison to non-diabetic rats, when the herbal mixture was added to Vaseline.

CONCLUSIONS

Our study presents an herbal treatment that alters the gene expression signature at wounds induced in the rat model for type I diabetes in a manner consistent with accelerated healing, and demonstrates that this herbal treatment might be effective to treat wounds in diabetic patients.

Growth Factor Variation in Two Types of Autologous Platelet Biomaterials: PRP Versus PRF

Autologous platelet biomaterials represent a key source of cytokines and growth factors extensively used for clinical and surgical applications involving tissue regeneration; wound healing and tissue repair. In this communication we discuss the growth factors released by activated platelet rich plasma (PRP) and platelet rich fibrin (PRF) releasate. Our study highlights that significantly higher growth factors (TGF-ß1) are released by activated PRP as compared to releasate of PRF. The various growth factors released by both platelet products are significantly higher than the baseline concentration in the whole blood and have different bio-mechanism hence should be individualized as per the clinical indication.

The TGF-β Signalling Network in Muscle Development, Adaptation and Disease

Skeletal muscle possesses remarkable ability to change its size and force-producing capacity in response to physiological stimuli. Impairment of the cellular processes that govern these attributes also affects muscle mass and function in pathological conditions. Myostatin, a member of the TGF-β family, has been identified as a key regulator of muscle development, and adaptation in adulthood. In muscle, myostatin binds to its type I (ALK4/5) and type II (ActRIIA/B) receptors to initiate Smad2/3 signalling and the regulation of target genes that co-ordinate the balance between protein synthesis and degradation. Interestingly, evidence is emerging that other TGF-β proteins act in concert with myostatin to regulate the growth and remodelling of skeletal muscle. Consequently, dysregulation of TGF-β proteins and their associated signalling components is increasingly being implicated in muscle wasting associated with chronic illness, ageing, and inactivity. The growing understanding of TGF-β biology in muscle, and its potential to advance the development of therapeutics for muscle-related conditions is reviewed here.

The Discovery and Early Days of TGF-β: A Historical Perspective

Transforming growth factors (TGFs) were discovered as activities that were secreted by cancer cells, and later by normal cells, and had the ability to phenotypically and reversibly transform immortalized fibroblasts. TGF-β distinguished itself from TGF-α because it did not bind to the same epidermal growth factor (EGF) receptor as TGF-α and, therefore, acted through different cell-surface receptors and signaling mediators. This review summarizes the discovery of TGF-β, the early developments in its molecular and biological characterization with its many biological activities in different cell and tissue contexts and its roles in disease, the realization that there is a family of secreted TGF-β-related proteins with many differentiation functions in development and activities in normal cell and tissue physiology, and the subsequent identification and characterization of the receptors and effectors that mediate TGF-β family signaling responses.

Signalling by Transforming Growth Factor Beta Isoforms in Wound Healing and Tissue Regeneration

Transforming growth factor beta (TGFβ) signalling is essential for wound healing, including both non-specific scar formation and tissue-specific regeneration. Specific TGFβ isoforms and downstream mediators of canonical and non-canonical signalling play different roles in each of these processes. Here we review the role of TGFβ signalling during tissue repair, with a particular focus on the prototypic isoforms TGFβ1, TGFβ2, and TGFβ3. We begin by introducing TGFβ signalling and then discuss the role of these growth factors and their key downstream signalling mediators in determining the balance between scar formation and tissue regeneration. Next we discuss examples of the pleiotropic roles of TGFβ ligands during cutaneous wound healing and blastema-mediated regeneration, and how inhibition of the canonical signalling pathway (using small molecule inhibitors) blocks regeneration. Finally, we review various TGFβ-targeting therapeutic strategies that hold promise for enhancing tissue repair.

Platelets drive smooth muscle metaplasia and fibrogenesis in endometriosis through epithelial-mesenchymal transition and fibroblast-to-myofibroblast transdifferentiation

Smooth muscle metaplasia (SMM) and fibrotic tissues are frequently seen in endometriotic lesions, yet the mechanisms underlying their formation are poorly understood. In this study, we investigated the roles of activated platelets in driving epithelial-mesenchymal transition (EMT) and fibroblast-to-myofibroblast transdifferentiation (FMT) in endometriosis. Through in vitro experimentations, we found that activated platelets, through the release of TGF-β1 and the induction of TGF-β/Smad signaling pathway, promoted EMT and FMT in endometriosis, resulting in increased cell contractility, collagen production, and ultimately to fibrosis. TGF-β blockade reversed these processes. Prolonged exposure of endometriotic stromal cells to activated platelets induced increased expression of α-SMA as well as markers of differentiated smooth muscle cells. Consequently, endometriotic lesions and their microenvironment contain all the necessary molecular machinery to promote SMM and fibrogenesis. Our results suggest that endometriotic lesions are wounds that undergo repeated injury and healing, highlighting the importance of platelets in the development of endometriosis.

Evidence of an interaction between TGF-β1 and the SDF-1/CXCR4/CXCR7 axis in human platelets

BACKGROUND

TGF-β1, SDF-1 and its cognate receptors CXCR4 and CXCR7 are expressed on the surface of human platelets and their expression levels are differently regulated in symptomatic coronary artery disease (CAD). All these proteins and receptors influence outcome in patients with symptomatic CAD. There might be a crosstalk between TGF-β1 and the SDF-1/CXCR4/CXCR7 axis. Interrelations in CAD, especially in the context of platelets, are poorly understood. Therefore, we aimed to provide clinical and experimental evidence of interactions between TGF-β1 and the SDF-1/CXCR4/CXCR7 axis in human platelets.

METHODS AND RESULTS

Blood samples of the complete cohort (n=284) were analysed for platelet surface expression levels of TGF-β1, SDF-1, CXCR4 and CXCR7 by flow cytometry. For stimulation assays platelet rich plasma was treated with TGF-β1 or SDF-1 and then analysed by flow cytometry. Multiple regression analyses were run to show independent associations of TGF-β1 with SDF-1, CXCR4, CXCR7 and clinical cofactors. Both, CXCR4 and CXCR7 significantly predicted TGF-β1 (p<0.001 and p<0.001, respectively). After stimulation with SDF-1, surface expression of TGF-β1 increased significantly when compared to resting platelets [mean TGF-β1 MFI 19.01 vs. mean TGF-β1 MFI 14.01, p<0.001]. Upon receptor blocking with either anti-CXCR4 or anti-CXCR7 monoclonal antibodies the enhancing effect of SDF-1 on TGF-β1 surface expression was significantly blunted. Stimulation with TGF-β1 did not alter SDF-1, CXCR4 or CXCR7 expression significantly.

CONCLUSIONS

We provide first clinical and experimental data suggesting a cross-talk between TGF-β and the SDF-1/CXCR4/CXCR7 axis in platelets which does not involve transcriptional modulation as shown previously for other cellular systems.

Synergistic effect of vitamin D and low concentration of transforming growth factor beta 1, a potential role in dermal wound healing

Dermal wound healing, in which transforming growth factor beta 1 (TGFβ1) plays an important role, is a complex process. Previous studies suggest that vitamin D has a potential regulatory role in TGFβ1 induced activation in bone formation, and there is cross-talk between their signaling pathways, but research on their effects in other types of wound healing is limited. The authors therefore wanted to explore the role of vitamin D and its interaction with low concentration of TGFβ1 in dermal fibroblast-mediated wound healing through an in vitro study. Human dermal fibroblasts were treated with vitamin D, TGFβ1, both, or vehicle, and then the wound healing functions of dermal fibroblasts were measured. To further explore possible mechanisms explaining the synergistic effect of vitamin D and TGFβ1, targeted gene silencing of the vitamin D receptor was performed. Compared to either factor alone, treatment of fibroblasts with both vitamin D and low concentration of TGFβ1 increased gene expression of TGFβ1, connective tissue growth factor, and fibronectin 1, and enhanced fibroblast migration, myofibroblast formation, and collagen production. Vitamin D receptor gene silencing blocked this synergistic effect of vitamin D and TGFβ1 on both collagen production and myofibroblast differentiation. Thus a synergistic effect of vitamin D and low TGFβ1 concentration was found in dermal fibroblast-mediated wound healing in vitro. This study suggests that supplementation of vitamin D may be an important step to improve wound healing and regeneration in patients with a vitamin D deficiency.

Platelet-derived TGF-β1 mediates the down-modulation of NKG2D expression and may be responsible for impaired natural killer (NK) cytotoxicity in women with endometriosis

STUDY QUESTION

Does platelet-derived transforming growth factor-β1 (TGF-β1) have any role in the reduced cytotoxicity of natural killer (NK) cells in women with endometriosis?

SUMMARY ANSWER

Platelet-derived TGF-β1 suppresses the expression of NK Group 2, Member D (NKG2D) on NK cells, resulting in reduced cytotoxicity in women with endometriosis, but neutralization of TGF-β1 reverses the reduction.

WHAT IS KNOWN ALREADY

NK cells are cytotoxic lymphocytes that play an important role in peritoneal immune surveillance, and their function is known to be impaired in women with endometriosis. There is increased platelet aggregation in endometriotic lesions and increased platelet activation rate in the peripheral blood in women with endometriosis, yet activated platelets release copiousTGF-β1, which is known to be a potent immunosuppressive molecule that suppresses NK cell function and NKG2D expression.

STUDY DESIGN, SIZE, DURATION

Cross-sectional clinical studies of 30 women with endometriosis and 33 women without endometriosis and in vitro experimentation with and without TGF-β1 blockade.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Peritoneal fluid (PF) samples from premenopausal women with endometriosis and age- and menstrual phase-matched controls were collected. Platelet count, white blood cell (WBC) count, mean platelet volume (MPV), platelet activation rate, TGF-β1 concentration, expression levels of NKG2D on NK cells in the PF were evaluated. The apoptosis of freshly isolated NK cells treated with PF from women with endometriosis, the NK cytotoxicity and NKG2D expression treated with PF in the presence or absence of an anti-TGF-β1 antibody were also determined.

MAIN RESULTS AND THE ROLE OF CHANCE

The platelet count, WBC count, MPV, platelet activation rate and the TGF-β1 concentration in the PF from women with endometriosis were significantly elevated when compared with those of women without endometriosis. The TGF-β1 concentration correlated positively with the platelet activation rate (r = 0.59, P < 0.01), suggesting that activated platelets are responsible, at least in part, for the increased TGF-β1 concentration. The cytotoxicity of freshly isolated NK cells treated with PF of women with endometriosis is significantly reduced when compared with that of women without endometriosis. Both the platelet activation rate and the TGF-β1 concentration in the PF correlated negatively with the NKG2D expression in NK cells isolated from the PF (r = -0.36, P < 0.01, and r = -0.45, P < 0.01, respectively). In addition, the NKG2D expression level and the cytotoxicity in freshly isolated NK cells were found to be significantly reduced if co-cultured with PF from women with endometriosis, but the TGF-β1 blockade effectively reverses the reduction.

LIMITATIONS, REASONS FOR CAUTION

This study is limited by the cross-sectional nature of the study.

WIDER IMPLICATIONS OF THE FINDINGS

NKG2D is known to potently activate NK cells, so potent that it even overrides inhibitory signals transduced by other inhibitory receptors. This is the first time we demonstrate that platelet-derived TGF-β1 may be responsible for reduced NKG2D expression as well as reduced cytotoxicity of NK cells in women with endometriosis. This study provides yet another piece of evidence that platelets play critical roles in the development of endometriosis, and anti-platelet treatment should improve NK cell functionality in treating endometriosis. Equally important, this study highlights the critical role of the lesion microenvironment in shaping NK cell-mediated anti-endometriotic immunity.

STUDY FUNDING/COMPETING INTERESTS

This research was supported in part by grants 81270676 (S.-W.G.), 81471434 (S.-W.G.), 81530040 (S.-W.G.), and 81370695 (X.L.) from the National Natural Science Foundation of China, and grant 2013ZYJB0019 (X.L.) from Shanghai Municipal Commission of Health and Family Planning. None of the authors has anything to disclose.

Thrombopoietin receptor agonists: a new immune modulatory strategy in immune thrombocytopenia?

In 2008, new drugs that mimic the effects of thrombopoietin became available for the treatment of primary immune thrombocytopenia, eg, romiplostim and eltrombopag. These drugs activate the thrombopoietin receptor, stimulate the production of megakaryocytes, and increase the production of platelets. Important clinical observation has been gained, such as unexpected long-term remission after stopping thrombopoietin receptor agonists. The pathophysiology of this unforeseen cure is currently the subject of discussion and is investigated in clinical trials and laboratory research projects. Here we evaluate the different hypotheses on how thrombopoietin receptor agonists can affect the immune system, particularly the induction of tolerance, and by which mechanisms this may be achieved.

The nonhemostatic immune functions of platelets

Platelets are megakaryocyte-derived cellular fragments, which lack a nucleus and are the smallest circulating cells and are classically known to have a major role in supporting hemostasis. Apart from this well-established role, it is now becoming evident that platelets are also capable of conveying other important functions, such as during infection and inflammation. This paper will outline these nonhemostatic functions in two major sections termed "Platelets versus pathogens" and "Platelet-target cell communication". Platelets actively contribute to protection against invading pathogens and are capable of regulating immune functions in various target cells, all through sophisticated and efficient mechanisms. These relatively novel features will be highlighted, illustrating the multifunctional role of platelets in inflammation.

Platelets and plasma stimulate sheep rotator cuff tendon tenocytes when cultured in an extracellular matrix scaffold

The addition of platelet-rich plasma (PRP) to rotator cuff repair has not translated into improved outcomes after surgery. However, recent work stimulating ligament healing has demonstrated improved outcomes when PRP or whole blood is combined with an extracellular matrix carrier. The objective of this study was to evaluate the effect of three components of blood (plasma, platelets, and macrophages) on the in vitro activity of ovine rotator cuff cells cultured in an extracellular matrix environment. Tenocytes were obtained from six ovine infraspinatus tendons and cultured over 14 days in an extracellular matrix scaffold with the following additives: (1) plasma (PPP), (2) plasma and platelets (PAP), (3) plasma and macrophages (PPPM), (4) plasma, platelets and macrophages (PAPM), (5) phosphate buffered saline (PBS), and (6) PBS with macrophages (PBSM). Assays measuring cellular metabolism (AlamarBlue), proliferation (Quantitative DNA assay), synthesis of collagen and cytokines (SIRCOL, TNF-α and IL-10 ELISA, and MMP assay), and collagen gene expression (qPCR) were performed over the duration of the experiment, as well as histology at the conclusion. Plasma was found to stimulate cell attachment and spreading on the scaffold, as well as cellular proliferation. Platelets also stimulated cell proliferation, cellular metabolism, transition of cells to a myofibroblast phenotype, and contraction of the scaffolds. The addition of macrophages did not have any significant effect on the sheep rotator cuff cells in vitro. In vivo studies are needed to determine whether these changes in cellular function will translate into improved tendon healing.

Characterization of a Decapentapletic Gene (AccDpp) from Apis cerana cerana and Its Possible Involvement in Development and Response to Oxidative Stress

To tolerate many acute and chronic oxidative stress-producing agents that exist in the environment, organisms have evolved many classes of signal transduction pathways, including the transforming growth factor β (TGFβ) signal pathway. Decapentapletic gene (Dpp) belongs to the TGFβ superfamily, and studies on Dpp have mainly focused on its role in the regulation of development. No study has investigated the response of Dpp to oxidative pressure in any organism, including Apis cerana cerana (A. cerana cerana). In this study, we identified a Dpp gene from A. cerana cerana named AccDpp. The 5΄ flanking region of AccDpp had many transcription factor binding sites that relevant to development and stress response. AccDpp was expressed at all stages of A. cerana cerana, with its highest expression in 15-day worker bees. The mRNA level of AccDpp was higher in the poison gland and midgut than other tissues. Furthermore, the transcription of AccDpp could be repressed by 4°C and UV, but induced by other treatments, according to our qRT-PCR analysis. It is worth noting that the expression level of AccDpp protein was increased after a certain time when A. cerana cerana was subjected to all simulative oxidative stresses, a finding that was not completely consistent with the result from qRT-PCR. It is interesting that recombinant AccDpp restrained the growth of Escherichia coli, a function that might account for the role of the antimicrobial peptides of AccDpp. In conclusion, these results provide evidence that AccDpp might be implicated in the regulation of development and the response of oxidative pressure. The findings may lay a theoretical foundation for further genetic studies of Dpp.

Gene therapy strategies to improve strength and quality of flexor tendon healing

INTRODUCTION

Rupture of the repair and adhesion around a tendon are two major problems after tendon surgery. Novel biological therapies which enhance healing and reduce adhesions are goals of many investigations. Gene therapy offers a new and promising approach to tackle these difficult problems. In the past decade, we sought to develop methods to augment tendon healing and reduce tendon adhesion through gene therapy.

AREAS COVERED

This review discusses the methods and results of adeno-associated viral (AAV) type 2 vector gene therapy to increase tendon healing strength and reduce adhesions in a chicken model. Micro-RNA related gene therapy is also discussed. We also developed a controlled release system, which incorporates nanoparticles to deliver micro-RNAs to regulate tendon healing.

EXPERT OPINION

We obtained promising results of enhancement of tendon healing strength in a chicken model using AAV2-mediated gene transfer. AAV2-mediated micro-RNA transfer also limited adhesions around the tendon. Controlled release systems incorporating nanoparticles have ideally delivered genes to the healing tendons and resulted in a moderate (but incomplete) reduction of adhesions. It remains to be determined what the best doses are and what other factors are in play in adhesion formation. These are two targets in our future investigations.

Transforming growth factor β1 signaling coincides with epithelial-mesenchymal transition and fibroblast-to-myofibroblast transdifferentiation in the development of adenomyosis in mice

STUDY QUESTION

Do platelets have any role in the development of adenomyosis?

SUMMARY ANSWER

Activated platelets coincide with the release of transforming growth factor (TGF)-β1 and induction of the TGF-β/Smad signaling pathway as well as evidence of epithelial-mesenchymal transition (EMT) and fibroblast-to-myofibroblast transdifferentiation (FMT) in a mouse model of adenomyosis, resulting ultimately in fibrosis, as in adenomyosis.

WHAT IS KNOWN ALREADY

Both EMT and FMT are known to play vital roles in fibrogenesis in general and in endometriosis in particular. EMT has been implicated in the development of adenomyosis, but this was based primarily on cross-sectional observation. It is unclear as to whether adenomyotic lesions and their microenvironment have the machinery to promote EMT and FMT, resulting ultimately in fibrosis. There has not been any published study on the role of platelets in the development of adenomyosis, even though adenomyotic lesions undergo repeated cycles of tissue injury and repair, which implicates the involvement of platelets and constitutes an environment conducive for fibrogenesis.

STUDY DESIGN, SIZE, DURATION

Adenomyosis was induced in 28 female ICR mice by neonatal dosing of tamoxifen. Another 32 were neonatally dosed without tamoxifen. These mice were sacrificed serially and their tissue samples were subsequently evaluated.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Female ICR mice with and without induced adenomyosis were sacrificed in batch at 5, 10, 15, 42 and 60 days of age. The depth of myometrial infiltration of endometrial tissues was assessed and immunohistochemistry analysis of biomarkers of EMT and FMT, as well as TGF-β1, phosphorylated Smad3 (p-Smad3) and markers of proliferation, angiogenesis and extracellular matrix (ECM) deposits was performed in ectopic (for adenomyotic mice) and eutopic (controls) endometrial tissue samples. Masson trichrome and Van Gieson stainings were performed to quantify the extent of fibrosis in lesions. Progesterone receptor isoform B (PR-B) staining also was performed.

MAIN RESULTS AND THE ROLE OF CHANCE

While TGF-β1 immunoreactivity was consistently low in control endometrium, its level was increased dramatically starting from Day 10, along with the extent of platelet aggregation. Staining for TGF-β1 and p-Smad3 increased progressively as adenomyosis progressed, along with markers for proliferation, angiogenesis and ECM deposits. Consistently, staining of vimentin (a marker for stromal or mesenchymal cells) was also increased while that of E-cadherin (a marker for epithelial cells) was reduced. PR-B staining also decreased progressively. Starting from Day 42, α-SMA staining, a marker for myofibroblasts, was elevated in lesions, while in control endometrium, it was negative. Concomitantly, the extent of fibrosis also was increased.

LIMITATIONS, REASONS FOR CAUTION

This study is limited by the use of histochemistry and immunohistochemistry analyses only and the lack of intervention.

WIDER IMPLICATIONS OF THE FINDINGS

Like their endometriotic counterpart, adenomyotic lesions and their microenvironment may contain all the necessary molecular machinery to promote fibrogenesis. Platelet-induced activation of the TGF-β/Smad signaling pathway may be a driving force in EMT and FMT in the development of adenomyosis, leading to fibrosis. This study provides the first piece of evidence that adenomyotic lesions are wounds that undergo repeated injury and healing, and as such, platelets play critical roles in the development of adenomyosis. It suggests the potential for the use of anti-platelet therapy in the treatment of adenomyosis, and also opens a new venue for developing novel biomarkers for diagnostic or prognostic purposes.

STUDY FUNDING/COMPETING INTERESTS

Support for data collection and analysis was provided by grants from the National Science Foundation of China. None of the authors has anything to disclose.

Co-expression of parathyroid hormone related protein and TGF-beta in breast cancer predicts poor survival outcome

Background

Better methods to predict prognosis can play a supplementary role in administering individualized treatment for breast cancer patients. Altered expressions of PTHrP and TGF-β have been observed in various types of human cancers. The objective of the current study was to evaluate the association of PTHrP and TGF-β level with the clinicopathological features of the breast cancer patients.

Methods

Immunohistochemistry was used to examine PTHrP and TGF-β protein expression in 497 cases of early breast cancer, and Kaplan-Meier method and COX’s Proportional Hazard Model were applied to the prognostic value of PTHrP and TGF-β expression.

Results

Both over-expressed TGF-β and PTHrP were correlated with the tumor in larger size, higher proportion of axillary lymph node metastasis and later clinical stage. Additionally, the tumors with a high TGF-β level developed poor differentiation, and only TGF-β expression was associated with disease-free survival (DFS) of the breast cancer patients. Followed up for a median of 48 months, it was found that only the patients with negative TGF-β expression had longer DFS (P < 0.05, log-rank test). Nevertheless, those with higher PTHrP expression tended to show a higher rate of bone metastasis (67.6 % vs. 45.8 %, P = 0.019). In ER negative subgroup, those who developed PTHrP positive expression presented poor prognosis (P < 0.05, log-rank test). The patients with both positive TGF-β and PTHrP expression were significantly associated with the high risk of metastases. As indicated by Cox’s regression analysis, TGF-β expression and the high proportion of axillary lymph node metastasis served as significant independent predictors for breast cancer recurrence.

Conclusions

TGF-β and PTHrP were confirmed to be involved in regulating the malignant progression in breast cancer, and PTHrP expression, to be associated with bone metastasis as a potential prognostic marker in ER negative breast cancer.

Inhibition of angiogenesis by platelets in systemic sclerosis patients

INTRODUCTION

Systemic sclerosis (SSc) is a chronic autoimmune disease characterized by microvascular damage, inflammation, and fibrosis. It has become increasingly evident that platelets, beyond regulating hemostasis, are important in inflammation and innate immunity. Platelets may be an important source of proinflammatory and profibrotic cytokines in the vascular microenvironment. In this study, we sought to assess the contribution of platelet-derived factors in patients with SSc to the angiogenesis of human dermal microvascular endothelial cells (DMVECs) in a tubule formation assay and to characterize the secretion of profibrotic and proinflammatory cytokines in these platelets.

METHODS

We analyzed platelets obtained from 30 patients with SSc and 12 healthy control subjects. Angiogenesis was evaluated in vitro with a DMVEC tubule formation assay on Matrigel and platelet-derived angiogenic factors such as vascular endothelial growth factor (VEGF), 165b isoform (VEGF165b), and cytokine secretion was evaluated. Platelet serotonin content was also determined.

RESULTS

When DMVECs were incubated with SSc platelet releasates, tubule formation was significantly inhibited (p < 0.01, t test), and higher expression of endothelin-1 in these cells was observed compared with control subjects (p < 0.05, Mann-Whitney U test). In SSc platelet releasates, VEGF165b was significantly higher (p < 0.05, t test), and the VEGF165b/VEGF ratio was increased compared with that of control subjects. Higher secretion of transforming growth factor β (p < 0.01, t test) and CD40L (p < 0.01, t test) was observed compared with control subjects. Also, intraplatelet serotonin levels were lower in platelets obtained from patients with diffuse SSc compared with patients with limited SSc and control subjects (p < 0.05, t test).

CONCLUSIONS

Our findings suggest that antiangiogenic factors such as VEGF165b, together with proinflammatory and profibrotic factors secreted by platelets, can contribute to the progression of peripheral microvascular damage, defective vascular repair, and fibrosis in patients with SSc.