Potential roles of bone morphogenetic protein (BMP)-9 in human liver diseases

Unveiling the Impact of BMP9 in Liver Diseases: Insights into Pathogenesis and Therapeutic Potential

Bone morphogenetic proteins (BMPs) are a group of growth factors belonging to the transforming growth factor β(TGF-β) family. While initially recognized for their role in bone formation, BMPs have emerged as significant players in liver diseases. Among BMPs with various physiological activities, this comprehensive review aims to delve into the involvement of BMP9 specifically in liver diseases and provide insights into the complex BMP signaling pathway. Through an enhanced understanding of BMP9, we anticipate the discovery of new therapeutic options and potential strategies for managing liver diseases.

Roles of transforming growth factor-β signaling in liver disease

In this editorial we expand the discussion on the article by Zhang et al published in the recent issue of the World Journal of Hepatology. We focus on the diagnostic and therapeutic targets identified on the basis of the current understanding of the molecular mechanisms of liver disease. Transforming growth factor-β (TGF-β) belongs to a structurally related cytokine super family. The family members display different time- and tissue-specific expression patterns associated with autoimmunity, inflammation, fibrosis, and tumorigenesis; and, they participate in the pathogenesis of many diseases. TGF-β and its related signaling pathways have been shown to participate in the progression of liver diseases, such as injury, inflammation, fibrosis, cirrhosis, and cancer. The often studied TGF-β/Smad signaling pathway has been shown to promote or inhibit liver fibrosis under different circumstances. Similarly, the early immature TGF-β molecule functions as a tumor suppressor, inducing apoptosis; but, its interaction with the mitogenic molecule epidermal growth factor alters this effect, activating anti-apoptotic signals that promote liver cancer development. Overall, TGF-β signaling displays contradictory effects in different liver disease stages. Therefore, the use of TGF-β and related signaling pathway molecules for diagnosis and treatment of liver diseases remains a challenge and needs further study. In this editorial, we aim to review the evidence for the use of TGF-β signaling pathway molecules as diagnostic or therapeutic targets for different liver disease stages.

Signaling pathways of liver regeneration: Biological mechanisms and implications

The liver possesses a unique regenerative ability to restore its original mass, in this regard, partial hepatectomy (PHx) and partial liver transplantation (PLTx) can be executed smoothly and safely, which has important implications for the treatment of liver disease. Liver regeneration (LR) can be the very complicated procedure that involves multiple cytokines and transcription factors that interact with each other to activate different signaling pathways. Activation of these pathways can drive the LR process, which can be divided into three stages, namely, the initiation, progression, and termination stages. Therefore, it is important to investigate the pathways involved in LR to elucidate the mechanism of LR. This study reviews the latest research on the key signaling pathways in the different stages of LR.

BMP9-ID1 Pathway Attenuates N6-Methyladenosine Levels of CyclinD1 to Promote Cell Proliferation in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a highly lethal malignant neoplasm, and the involvement of bone morphogenetic protein 9 (BMP9) has been implicated in the pathogenesis of liver diseases and HCC. Our goal was to investigate the role of BMP9 signaling in regulating N6-methyladenosine (m6A) methylation and cell cycle progression, and evaluate the therapeutic potential of BMP receptor inhibitors for HCC treatment. We observed that elevated levels of BMP9 expression in tumor tissues or serum samples from HCC patients were associated with a poorer prognosis. Through in vitro experiments utilizing the m6A dot blotting assay, we ascertained that BMP9 reduced the global RNA m6A methylation level in Huh7 and Hep3B cells, thereby facilitating their cell cycle progression. This effect was mediated by an increase in the expression of the inhibitor of DNA-binding protein 1 (ID1). Additionally, using methylated RNA immunoprecipitation qPCR(MeRIP-qPCR), we showed that the BMP9-ID1 pathway promoted CyclinD1 expression by decreasing the m6A methylation level in the 5' UTR of mRNA. This occurred through the upregulation of the fat mass and obesity-associated protein (FTO) in Huh7 and Hep3B cells. In our in vivo mouse xenograft models, we demonstrated that blocking the BMP receptor with LDN-212854 effectively suppressed HCC growth and induced global RNA m6A methylation. Overall, our findings indicate that the BMP9-ID1 pathway promotes HCC cell proliferation by down-regulating the m6A methylation level in the 5' UTR of CyclinD1 mRNA. Targeting the BMP9-ID1 pathway holds promise as a potential therapeutic strategy for treating HCC.

BMP9 is a potent inducer of chondrogenesis, volumetric expansion and collagen type II accumulation in bovine auricular cartilage chondroprogenitors

Reconstruction of the outer ear currently requires harvesting of cartilage from the posterior of the auricle or ribs leading to pain and donor site morbidity. An alternative source for auricular reconstruction is in vitro tissue engineered cartilage using stem/progenitor cells. Several candidate cell-types have been studied with tissue-specific auricular cartilage progenitor cells (AuCPC) of particular interest. Whilst chondrogenic differentiation of competent stem cells using growth factor TGFβ1 produces cartilage this tissue is frequently fibrocartilaginous and lacks the morphological features of hyaline cartilage. Recent work has shown that growth factor BMP9 is a potent chondrogenic and morphogenetic factor for articular cartilage progenitor cells, and we hypothesised that this property extends to cartilage-derived progenitors from other tissues. In this study we show monoclonal populations of AuCPCs from immature and mature bovine cartilage cultured with BMP9 produced cartilage pellets have 3-5-fold greater surface area in sections than those grown with TGFβ1. Increased volumetric growth using BMP9 was due to greater sGAG deposition in immature pellets and significantly greater collagen accumulation in both immature and mature progenitor pellets. Polarised light microscopy and immunohistochemical analyses revealed that the organisation of collagen fibrils within pellets is an important factor in the growth of pellets. Additionally, chondrocytes in BMP9 stimulated cell pellets had larger lacunae and were more evenly dispersed throughout the extracellular matrix. Interestingly, BMP9 tended to normalise the response of immature AuCPC monoclonal cell lines to differentiation cues whereas cells exhibited more variation under TGFβ1. In conclusion, BMP9 appears to be a potent inducer of chondrogenesis and volumetric growth for AuCPCs a property that can be exploited for tissue engineering strategies for reconstructive surgery though with the caveat of negligible elastin production following 21-day treatment with either growth factor.

Bone morphogenetic protein (BMP)9 in cancer development: mechanistic, diagnostic, and therapeutic approaches?

Bone morphogenetic protein (BMP)-9 is considered a member of the transforming growth factor (TGF)β superfamily. It was first found as an inducer of bone and cartilage formation and then discovered that this factor mediates several physiologic functions and hemostasis. Besides physiological conditions, BMP9 has also been elucidated that it is involved in several pathological situations, especially cancer. In various cancers, dysregulation of BMP9 has raised the issue that BMP9 might play a conflicting role in tumour development. BMP9 binding to its receptors (BMPRs), including ALKs and BMPRII, induces canonical SMAD-dependent and non-canonical PI3K/AKT and MAPK signalling pathways in tumour cells. BMP9, via inducing apoptosis, inhibiting tumour-promoting cell signalling pathways, suppressing epithelial-mesenchymal transition (EMT) process, blocking angiogenesis, and preventing cross-talk in the tumour microenvironment, mainly exerts tumour-suppressive functions. In contrast, BMP9 triggers tumour-supportive signalling pathways, promotes EMT, and enhances angiogenesis, suggesting that BMP9 is also involved in tumour development. It has been demonstrated that modulating BMP9 expression and functions might be a promising approach to cancer treatment. It has also been indicated that evaluating BMP9 expression in cancers might be a biomarker for predicting cancer prognosis. Overall, BMP9 would provide a promising target in cancer management.

Metabolic Health and Disease: A Role of Osteokines?

Maintenance of skeletal health is tightly regulated by osteocytes, osteoblasts, and osteoclasts via coordinated secretion of bone-derived factors, termed osteokines. Disruption of this coordinated process due to aging and metabolic disease promotes loss of bone mass and increased risk of fracture. Indeed, growing evidence demonstrates that metabolic diseases, including type 2 diabetes, liver disease and cancer are accompanied by bone loss and altered osteokine levels. With the persistent prevalence of cancer and the growing epidemic of metabolic disorders, investigations into the role of inter-tissue communication during disease progression are on the rise. While osteokines are imperative for bone homeostasis, work from us and others have identified that osteokines possess endocrine functions, exerting effects on distant tissues including skeletal muscle and liver. In this review we first discuss the prevalence of bone loss and osteokine alterations in patients with type 2 diabetes, non-alcoholic fatty liver disease, non-alcoholic steatohepatitis, cirrhosis, and cancer. We then discuss the effects of osteokines in mediating skeletal muscle and liver homeostasis, including RANKL, sclerostin, osteocalcin, FGF23, PGE2, TGF-β, BMPs, IGF-1 and PTHrP. To better understand how inter-tissue communication contributes to disease progression, it is essential that we include the bone secretome and the systemic roles of osteokines.

BMP9 Promotes an Epithelial Phenotype and a Hepatocyte-like Gene Expression Profile in Adult Hepatic Progenitor Cells

Bone morphogenetic protein 9 (BMP9), a member of the TGF-β superfamily, has emerged as a new player in chronic liver diseases (CLDs). Its levels increase in the fibrotic liver where it promotes fibrogenesis. It also regulates hepatic progenitor cells (oval cells in rodents), a cell population that contributes to repopulate the liver and recover functionality upon severe damage, but it can also be pro-fibrogenic, depending upon the hepatic microenvironment. Here we analyze the effect of chronic exposure to BMP9 in oval cells. We show that cells chronically treated with BMP9 (B9T-OC) display a more epithelial and hepatocyte-like phenotype while acquiring proliferative and survival advantages. Since our previous studies had revealed a functional crosstalk between BMP9 and the HGF/c-Met signaling pathways in oval cells, we analyzed a possible role for HGF/c-Met in BMP9-induced long-term effects. Data evidence that active c-Met signaling is necessary to obtain maximum effects in terms of BMP9-triggered hepatocytic differentiation potential, further supporting functionally relevant cooperation between these pathways. In conclusion, our work reveals a novel action of BMP9 in liver cells and helps elucidate the mechanisms that serve to increase oval cell regenerative potential, which could be therapeutically modulated in CLD.

Strategies for Improving Photodynamic Therapy Through Pharmacological Modulation of the Immediate Early Stress Response

Photodynamic therapy (PDT) is a minimally to noninvasive treatment modality that has emerged as a promising alternative to conventional cancer treatments. PDT induces hyperoxidative stress and disrupts cellular homeostasis in photosensitized cancer cells, resulting in cell death and ultimately removal of the tumor. However, various survival pathways can be activated in sublethally afflicted cancer cells following PDT. The acute stress response is one of the known survival pathways in PDT, which is activated by reactive oxygen species and signals via ASK-1 (directly) or via TNFR (indirectly). The acute stress response can activate various other survival pathways that may entail antioxidant, pro-inflammatory, angiogenic, and proteotoxic stress responses that culminate in the cancer cell's ability to cope with redox stress and oxidative damage. This review provides an overview of the immediate early stress response in the context of PDT, mechanisms of activation by PDT, and molecular intervention strategies aimed at inhibiting survival signaling and improving PDT outcome.

The Dual Effect of the BMP9-ALK1 Pathway in Blood Vessels: An Opportunity for Cancer Therapy Improvement?

Simple Summary

The modulation of tumor blood vessels is a great opportunity for improving cancer therapies. Understanding the cellular and molecular players that regulate the biology of tumor blood vessels and tumor angiogenesis is necessary for the development of new anti-tumor strategies. Bone morphogenetic protein 9 (BMP9) is a circulating factor with multiple effects in vascular biology through its receptor activin receptor-like kinase 1 (ALK1). In this review, we give an overview of the possible benefits of modulating BMP9–ALK1 functions for cancer therapy improvement.

Abstract

The improvement of cancer therapy efficacy, the extension of patient survival and the reduction of adverse side effects are major challenges in cancer research. Targeting blood vessels has been considered a promising strategy in cancer therapy. Since the tumor vasculature is disorganized, leaky and triggers immunosuppression and tumor hypoxia, several strategies have been studied to modify tumor vasculature for cancer therapy improvement. Anti-angiogenesis was first described as a mechanism to prevent the formation of new blood vessels and prevent the oxygen supply to tumor cells, showing numerous limitations. Vascular normalization using low doses of anti-angiogenic drugs was purposed to overcome the limitations of anti-angiogenic therapies. Other strategies such as vascular promotion or the induction of high endothelial venules are being studied now to improve cancer therapy. Bone morphogenetic protein 9 (BMP9) exerts a dual effect through the activin receptor-like kinase 1 (ALK1) receptor in blood vessel maturation or activation phase of angiogenesis. Thus, it is an interesting pathway to target in combination with chemotherapies or immunotherapies. This review manuscript explores the effect of the BMP9–ALK1 pathway in tumor angiogenesis and the possible usefulness of targeting this pathway in anti-angiogenesis, vascular normalization or vascular promotion therapies.

Effects of bone morphogenetic proteins on epithelial repair

Epithelial tissue has important functions such as protection, secretion, and sensation. Epithelial damage is involved in various pathological processes. Bone morphogenetic proteins (BMPs) are a class of growth factors with multiple functions. They play important roles in epithelial cells, including in differentiation, proliferation, and migration during the repair of the epithelium. This article reviews the functions and mechanisms of the most profoundly studied BMPs in the process of epithelial damage repair and their clinical significance.

New insights into BMP9 signaling in liver diseases

Bone morphogenetic protein 9 (BMP9) is a recently discovered cytokine mainly secreted by the liver and is a member of the transforming growth factor β (TGF-β) superfamily. In recent years, an increasing number of studies have shown that BMP9 is associated with liver diseases, including nonalcoholic fatty liver disease (NAFLD), liver fibrosis and hepatocellular carcinoma (HCC), and BMP9 signaling may play dual roles in liver diseases. In this review, we mainly summarized and discussed the roles and potential mechanisms of BMP9 signaling in NAFLD, liver fibrosis and HCC. Specifically, this article will provide a better understanding of BMP9 signaling and new clues for the treatment of liver diseases.

The Role of Bone Morphogenetic Protein 9 in Nonalcoholic Fatty Liver Disease in Mice

Background and Aims: It’s reported that bone morphogenetic protein 9 (BMP9) played an important role in lipid and glucose metabolism, but the role of BMP9 in nonalcoholic fatty liver disease (NAFLD) is unclear. Here, we evaluated the therapeutic efficacy of recombined BMP9 in NAFLD mice and investigated the potential mechanism.

Methods: The effects of recombinant BMP9 on NAFLD were assessed in HFD-induced NAFLD mice. C57BL/6 mice were administrated with high-fat diet (HFD) for 12 weeks. In the last 4 weeks, mice were treated with PBS or recombined BMP9 once daily. Insulin sensitivity was evaluated by glucose tolerance test (GTT) and insulin tolerance test (ITT) at the end of the 12th week. Then NAFLD related indicators were assessed by a variety of biological methods, including histology, western blotting, real-time PCR, RNA-seq and assay for transposase-accessible chromatin using sequencing (ATAC-seq) analyses.

Results: BMP9 reduced obesity, improved glucose metabolism, alleviated hepatic steatosis and decreased liver macrophages infiltration in HFD mice. RNA-seq showed that Cers6, Cidea, Fabp4 involved in lipid and glucose metabolism and Fos, Ccl2, Tlr1 involved in inflammatory response downregulated significantly after BMP9 treatment in HFD mouse liver. ATAC-seq showed that chromatin accessibility on promoters of Cers6, Fabp4, Ccl2 and Fos decreased after BMP9 treatment in HFD mouse liver. KEGG pathway analysis of dysregulated genes in RNA-seq and integration of RNA-seq and ATAC-seq showed that TNF signaling pathway and Toll-like receptor signaling pathway decreased in BMP9 treated HFD mouse liver.

Conclusion: Our data revealed that BMP9 might alleviate NAFLD via improving glucose and lipid metabolism, decreasing inflammatory response and reshaping chromatin accessibility in HFD mouse liver. BMP9 downregulate genes related to lipid metabolism, glucose metabolism and inflammation expression, at least partially via decreasing promoter chromatin accessibility of Cers6, Fabp4, Fos and Tlr1. BMP9 may also reduce the expression of liver Ccl2, thereby changing the number or composition of liver macrophages, and ultimately reducing liver inflammation. The effect of BMP9 on NAFLD might be all-round, and not limit to lipid and glucose metabolism. Therefore, the underlying mechanism needs to be studied in detail further.

Evaluating Distribution and Prognostic Value of New Tumor-Infiltrating Lymphocytes in HCC Based on a scRNA-Seq Study With CIBERSORTx

Hepatocellular carcinoma (HCC) is a commonly diagnosed cancer with high mortality rates. The immune response plays an important role in the progression of HCC. Immunotherapies are becoming an increasingly promising tool for treating cancers. Advancements in scRNA-seq (single-cell RNA sequencing) have allowed us to identify new subsets in the immune microenvironment of HCC. Yet, distribution of these new cell types and their potential prognostic value in bulk samples from large cohorts remained unclear. This study aimed to investigate the tumor-infiltration and prognostic value of new cell subsets identified by a previous scRNA-seq study in a TCGA HCC cohort using CIBERSORTx, a machine learning method to estimate cell proportion and infer cell-type-specific gene expression profiles. We observed different distributions of tumor-infiltrating lymphocytes between tumor and normal cells. Among these, the CD4-GZMA cell subset showed association with prognosis (log-rank test, p < 0.05). We further analyzed CD4-GZMA cell specific gene expression with CIBERSORTx, and found 19 prognostic genes (univariable cox regression, p < 0.05). Finally, we applied Least absolute shrinkage and selection operator (LASSO) Cox regression to construct an immune risk score model and performed a prognostic assessment of our model in TCGA and ICGC cohorts. Taken together, the immune landscape in HCC bulk samples may be more complex than assumed, with heterogeneity and different tumor-infiltration relative to scRNA-seq results. Additionally, CD4-GZMA cells and their characteristics may yield therapeutic benefits in the immune treatment of HCC.

Potential roles of bone morphogenetic protein-9 in glucose and lipid homeostasis

Bone morphogenetic protein-9 (BMP-9) is a novel cytokine which is cloned from the fetal mouse liver cDNA library and belongs to the member of the transforming growth factor-β (TGF-β) superfamily. BMP-9 is mainly secreted by the liver and exerts a variety of physiological functions. In this review, we present the latest knowledge on the biochemistry of BMP-9 and its role in glucose metabolism and lipid homeostasis. We introduced the expression site, structure, synthesis, and secretion of BMP-9, as well as BMP-9 signaling pathway. We also discuss the effects of BMP-9 on glucose metabolism and lipid metabolism in different organs. BMP-9 can regulate glucose and lipid homeostasis in the body by inhibiting liver gluconeogenesis, transforming white adipose tissue to brown adipose tissue, promoting muscle glycogen synthesis, increasing the uptake and utilization of glucose by muscle tissue, increasing liver and adipose tissue insulin sensitivity, promoting insulin synthesis and secretion, inhibiting liver lipid deposition, and playing a leptin-like role. Finally, through the results of animal intervention studies and human clinical studies in the review, we deeply understand the association of BMP-9 with obesity, insulin resistance (IR), type 2 diabetes, and non-alcoholic fatty liver disease (NAFLD), which provides new ideas for the prevention and treatment of diseases.

Endothelial protective factors BMP9 and BMP10 inhibit CCL2 release by human vascular endothelial cells

Bone morphogenetic protein 9 (BMP9) and BMP10 are circulating ligands that mediate endothelial cell (EC) protection via complexes of the type I receptor ALK1 and the type II receptors activin type-IIA receptor (ACTR-IIA) and bone morphogenetic type II receptor (BMPR-II). We previously demonstrated that BMP9 induces the expression of interleukin-6, interleukin-8 and E-selectin in ECs and might influence their interactions with monocytes and neutrophils. We asked whether BMP9 and BMP10 regulate the expression of chemokine (C-C motif) ligand 2 (CCL2), a key chemokine involved in monocyte-macrophage chemoattraction. Here, we show that BMP9 and BMP10 repress basal CCL2 expression and release from human pulmonary artery ECs and aortic ECs. The repression was dependent on ALK1 and co-dependent on ACTR-IIA and BMPR-II. Assessment of canonical Smad signalling indicated a reliance of this response on Smad4. Of note, Smad1/5 signalling contributed only at BMP9 concentrations similar to those in the circulation. In the context of inflammation, BMP9 did not alter the induction of CCL2 by TNF-α. As CCL2 promotes monocyte/macrophage chemotaxis and endothelial permeability, these data support the concept that BMP9 preserves basal endothelial integrity.

BMP-9 Modulates the Hepatic Responses to LPS

It was previously shown that Bone Morphogenetic Protein (BMP)-9 is constitutively produced and secreted by hepatic stellate cells (HSC). Upon acute liver damage, BMP-9 expression is transiently down-regulated and blocking BMP-9 under conditions of chronic damage ameliorated liver fibrogenesis in C57BL/6 mice. Thereby, BMP-9 acted as a pro-fibrogenic cytokine in the liver but without directly activating isolated HSC in vitro. Lipopolysaccharide (LPS), an endotoxin derived from the membrane of Gram-negative bacteria in the gut, is known to be essential in the pathogenesis of diverse kinds of liver diseases. The aim of the present project was therefore to investigate how high levels of BMP-9 in the context of LPS signalling might result in enhanced liver damage. For this purpose, we stimulated human liver sinusoidal endothelial cells (LSEC) with LPS and incubated primary human liver myofibroblasts (MF) with the conditioned medium of these cells. We found that LPS led to the secretion of factors from LSEC that upregulate BMP-9 expression in MF. At least one of these BMP-9 enhancing factors was defined to be IL-6. High BMP-9 in turn, especially in combination with LPS stimulation, induced the expression of certain capillarization markers in LSEC and enhanced the LPS-mediated induction of pro-inflammatory cytokines in primary human macrophages. In LSEC, pre-treatment with BMP-9 reduced the LPS-mediated activation of the NfkB pathway, whereas in macrophages, LPS partially inhibited the BMP-9/Smad-1 signaling cascade. In vivo, in mice, BMP-9 led to the enhanced presence of F4/80-positive cells in the liver and it modulated the LPS-mediated regulation of inflammatory mediators. In summary, our data point to BMP-9 being a complex and highly dynamic modulator of hepatic responses to LPS: Initial effects of LPS on LSEC led to the upregulation of BMP-9 in MF but sustained high levels of BMP-9 in turn promote pro-inflammatory reactions of macrophages. Thereby, the spatial and timely fine-tuned presence (or absence) of BMP-9 is needed for efficient wound-healing responses in the liver.

Genome-wide comparative analysis ofbone morphogenetic proteins: genomic structure, phylogeny, and expression patterns in the golden pompano,Trachinotus ovatus(Linnaeus, 1758)

Bone morphogenetic proteins (BMPs) play important roles in various physiological processes, especially during the formation and maintenance of various organs. In this study, we first obtained and characterized twenty BMP genes from the Trachinotus ovatus genome (designated as ToBMPs). Sequence alignment and phylogenetic analysis both indicated that the predicted amino acid sequences of ToBMP were highly conserved with corresponding homologs of other species. Moreover, a comparative analysis was performed with seven representative vertebrate genomes and found difference in number of BMP3 genes in different species, which three members, BMP3a, BMP3b-1, and BMP3b-2, existed in diploid T. ovatus, but there were four and two members in tetraploidized Cyprinus carpio (BMP3a-1, BMP3a-2, BMP3b-1, and BMP3b-2) and diploid Danio rerio (BMP3a and BMP3b), respectively. The amino acid alignment and genomic structure analysis of ToBMP3 also suggested that the BMP3 gene had expanded in T. ovatus. Furthermore, tissue expression patterns were assessed for the small intestine, liver, white muscle, brain, spleen, fin, gill, head kidney, stomach, blood, and gonads. It was discovered that BMP1, BMP2, BMP3a, BMP4, BMP6, BMP7b, BMP11, and BMP16 were ubiquitously expressed in all the tissues tested. To study the regulatory function of BMP in response to the intake of different types of food, the expression changes in BMP mRNAs were detected by qRT-PCR, and the results showed that the majority of the BMP genes had the highest mRNA levels in the small intestine and liver after ingesting pelleted feed. Our data provide a useful resource for further studies on how paralogous genes may have different expression profiles in T. ovatus.

BMP-9 is a novel marker for colorectal tumorigenesis undergoing the normal mucosa-adenoma-adenocarcinoma sequence and is associated with colorectal cancer prognosis

Depending on the type of cancer, bone morphogenetic protein-9 (BMP-9) can promote or inhibit tumorigenesis; however, the function of BMP-9 in colorectal cancer remains unclear. The aim of the present study was to evaluate the clinicopathological importance of BMP-9 expression in the tumorigenesis of normal colorectal epithelial tissue, and subsequent transformation into adenoma and carcinoma. In addition, the present study aimed to determine the prognostic value of BMP-9 on the survival of patients with colorectal cancer (CRC). A total of 65 patients with pathologically confirmed colorectal adenocarcinoma and a history of adenoma were enrolled. BMP-9 and Ki-67 expression was assessed retrospectively using paraffin-embedded samples of normal colorectal mucosa, colorectal adenoma and CRC obtained from each patient. The prognostic value of BMP-9 expression was analyzed in a group comprising 48 patients with CRC and a mean follow-up duration of 39.1 months. Bioinformatics analyses were performed in order to validate the results of the present study using published CRC datasets. The results from the present study suggested that the expression of BMP-9 gradually increased during the transition from normal mucosa to adenoma and subsequent adenocarcinoma (P<0.05); however, no significant association between the expression levels of BMP-9 and the clinicopathological parameters of patients was reported. Kaplan-Meier analysis revealed that patients with high expression levels of BMP-9 exhibited shorter overall survival rate than those with low levels of expression (54.7 vs. 41.3 months; log-rank test, P<0.05). Furthermore, regardless of tumor location and the presence of blood vessel tumor emboli, the univariate and multivariate analyses indicated that BMP-9 expression may be an independent prognostic factor for the overall survival rate of patients with CRC. The results of the present study suggested that BMP-9 may serve an oncogenic role and possess prognostic value in CRC.

CD105 overexpression mediates drug-resistance in choriocarcinoma cells through BMP9/Smad pathway

Background: CD105 (endoglin, ENG) is a membranous protein that is overexpressed in tumor-associated endothelial cells and some actual tumor cells and is associated with poor prognosis. However, the association between CD105 and response to chemoresistance in choriocarcinoma cells has not been clearly defined. The present study aimed to investigate the effects of targeting CD105 in drug-resistant choriocarcinoma.

Methods: CD105 expression was evaluated in drug-resistant and parental choriocarcinoma cells by qRT-PCR, western blotting, and immunofluorescence. CD105 overexpressing and knockdown cells were established by lentiviral transfection. CCK8, transwell, and flow cytometric assays were used to measure changes in drug-sensitivity, invasion, migration, and apoptosis. Drug-sensitivity and Smad1/5/8, Smad2, and Smad3 expression were also detected after BMP9 treatment. Immunohistochemical staining for CD105 and BMP9 was performed on choriocarcinoma tissues and the relationships between clinical and pathological characteristics were analysed.

Results: Data demonstrated that CD105 overexpression could decrease drug sensitivity, promote invasion and migration, and inhibit apoptosis in choriocarcinoma cells, and this protein was confirmed to mediate drug resistance through the BMP9/Smad pathway. Further experiments showed that the expression of CD105 and BMP9 was consistent in choriocarcinoma tissues and significantly associated with disease recurrence.

Conclusions: This study provides evidence suggesting that CD105 is critical for the development of drug-resistance in choriocarcinoma and might serve as a therapeutic target for reversing chemoresistance in choriocarcinoma patients.

Bioengineering strategies for bone and cartilage tissue regeneration using growth factors and stem cells

Bone and cartilage tissue engineering is an integrative approach that is inspired by the phenomena associated with wound healing. In this respect, growth factors have emerged as important moieties for the control and regulation of this process. Growth factors act as mediators and control the important physiological functions of bone regeneration. Herein, we discuss the importance of growth factors in bone and cartilage tissue engineering, their loading and delivery strategies, release kinetics, and their integration with biomaterials and stem cells to heal bone fractures. We also highlighted the role of growth factors in the determination of the bone tissue microenvironment based on the reciprocal signaling with cells and biomaterial scaffolds on which future bone and cartilage tissue engineering technologies and medical devices will be based upon.

Differential Consequences of Bmp9 Deletion on Sinusoidal Endothelial Cell Differentiation and Liver Fibrosis in 129/Ola and C57BL/6 Mice

The aim of the present work was to address the role of BMP9 in different genetic backgrounds (C57BL/6, BALB/c, and 129/Ola) of mice deleted for Bmp9. We found that Bmp9 deletion led to premature mortality only in the 129/Ola strain. We have previously shown that Bmp9 deletion led to liver sinusoidal endothelial cells (LSEC) capillarization and liver fibrosis in the 129/Ola background. Here, we showed that this is not the case in the C57BL/6 background. Analysis of LSEC from Wild-type (WT) versus Bmp9-KO mice in the C57BL/6 background showed no difference in LSEC fenestration and in the expression of differentiation markers. Comparison of the mRNA expression of LSEC differentiation markers between WT C57BL/6 and 129/Ola mice showed a significant decrease in Stabilin2, Plvap, and CD209b, suggesting a more capillary-like phenotype in WT C57BL/6 LSECs. C57BL/6 mice also had lower BMP9 circulating concentrations and hepatic Vegfr2 mRNA levels, compared to the 129/Ola mice. Taken together, our observations support a role for BMP9 in liver endothelial cell fenestration and prevention of fibrosis that is dependent on genetic background. It also suggests that 129/Ola mice are a more suitable model than C57BL/6 for the study of liver fibrosis subsequent to LSEC capillarization.

BMP2 secretion from hepatocellular carcinoma cell HepG2 enhances angiogenesis and tumor growth in endothelial cells via activation of the MAPK/p38 signaling pathway

Background

Hepatocellular carcinoma (HCC) is one of the most common tumors globally, with varying prevalence based on endemic risk factors. Bone morphogenetic protein (BMP) exhibits a broad spectrum of biological activities in various tissues including angiogenesis. Here, this study aimed to investigate the mechanism of BMP2 in HCC by mediating the mitogen-activated protein kinase (MAPK)/p38 signaling pathway.

Methods

BMP2 expression was quantified in HCC and adjacent tissues. BMP2 gain- and loss-of-function experiments were conducted by infection with lentivirus over-expressing BMP2 or expressing shRNA against BMP2. The angiogenesis was evaluated with HepG2 cells co-cultured with ECV304 cells. SB-239063 was applied to inhibit the activation of the MAPK/p38 signaling pathway so as to identify the significance of this pathway in HCC progression. Finally, in vivo experiments were conducted to identify the role of BMP2 and the MAPK/p38 signaling pathway in tumor growth and angiogenesis.

Results

BMP2 was highly expressed in HCC. Over-expression of BMP2 was found to accelerate cell proliferation, migration, invasion, microvascular density, and angiogenesis and decrease cell apoptosis in vitro and in vivo. BMP2 silencing exhibited inhibitory effects on HCC cell invasion and angiogenesis. The co-culture system illustrated that HepG2 cells secreted BMP2 in ECV304, and silenced BMP2 in HepG2 cells resulted in the inactivation of the MAPK/p38 signaling pathway, thus suppressing cancer progression, tumor growth, and angiogenesis in HCC.

Conclusion

Taken together, the key findings of this study propose that silencing of BMP2 inhibits angiogenesis and tumor growth in HCC, highlighting BMP2 silencing as a potential strategy for the treatment of HCC.

Adenovirus‑mediated overexpression of bone morphogenetic protein‑9 promotes methionine choline deficiency‑induced non‑alcoholic steatohepatitis in non‑obese mice

Liver inflammation and macrophage infiltration are critical steps in the progression of non‑alcoholic fatty liver to the development of non‑alcoholic steatohepatitis. Bone morphogenetic protein‑9 is a cytokine involved in the regulation of chemokines and lipogenesis. However, the function of bone morphogenetic protein‑9 in non‑alcoholic steatohepatitis is still unknown. The present study hypothesized that bone morphogenetic protein‑9 may contribute to steatohepatitis in mice fed a methionine choline deficiency diet (MCD). C57BL/6 mice overexpressing bone morphogenetic protein‑9 and control mice were fed the MCD diet for 4 weeks. Liver tissue and serum samples were obtained for subsequent measurements. Bone morphogenetic protein‑9 overexpression exacerbated steatohepatitis in mice on the MCD diet, as indicated by liver histopathology, increased serum alanine aminotransferase activity, aspartate transaminase activity, hepatic inflammatory gene expression and M1 macrophage recruitment. Although bone morphogenetic protein‑9 overexpression did not affect the expression of pro‑fibrogenic genes, including Collagen I (α)1 or matrix metalloproteinase (MMP) 9, it did upregulate the expression of transforming growth factor‑β and plasminogen activator inhibitor 1, and downregulated the expression of MMP2. The above results indicate that bone morphogenetic protein‑9 exerts a pro‑inflammatory role in MCD diet‑induced non‑alcoholic steatohepatitis.

Epithelial‑mesenchymal transition induced by bone morphogenetic protein 9 hinders cisplatin efficacy in ovarian cancer cells

Bone morphogenetic protein 9 (BMP9) belongs to the transforming growth factor-β (TGF-β) superfamily, and has been reported to promote cancer cell proliferation and epithelial-mesenchymal transition (EMT). Cisplatin (DDP) is the first line treatment for ovarian cancer. However, initiation of EMT confers insensitivity to chemotherapy. The present study aimed to verify and examine the mechanisms underlying the effects of BMP9 on treatment with DDP for ovarian cancer. Prior to treatment with DDP, ovarian cancer cells were exposed to BMP9 for 3 days. Following this, cell viability, apoptosis rate and the extent of DNA damage were evaluated to compare the effects of DDP on BMP9-pretreated and non-pretreated ovarian cancer cells. In addition, EMT marker expression was evaluated by western blotting and immunofluorescence. The results demonstrated that BMP9 pretreatment inhibited the cytotoxicity of DDP on ovarian cancer cells. Additionally, BMP9-pretreated ovarian cancer cells had downregulated expression of the epithelial marker E-cadherin, which was accompanied by an upregulation of the mesenchymal markers N-cadherin, Snail, Slug, and Twist. Taken together, the findings of the present study indicated that BMP9 conferred resistance to DDP in ovarian cancer cells by inducing EMT. The present study provided valuable insight into the mechanisms of chemotherapy in ovarian cancer and highlighted the potential of BMP9 as a novel therapeutic target for improving cisplatin chemosensitivity.

Prostate Osteoblast-Like Cells: A Reliable Prognostic Marker of Bone Metastasis in Prostate Cancer Patients

The main aim of this study was to investigate the putative association among the presence of prostate cancer cells, defined as prostate osteoblast-like cells (POLCs), and showing the expression of typical morphological and molecular characteristics of osteoblasts, the development of bone metastasis within 5 years of diagnosis, and the uptake of 18F-choline evaluated by PET/CT analysis. To this end, prostate biopsies (n = 110) were collected comprising 44 benign lesions and 66 malignant lesions. Malignant lesions were further subdivided into two groups: biopsies from patients that had clinical evidence of bone metastasis (BM+, n = 23) and biopsies from patients that did not have clinical evidence of bone metastasis within 5 years (BM-, n = 43). Paraffin serial sections were obtained from each specimen to perform histological classifications and immunohistochemical (IHC) analysis. Small fragments of tissue were used to perform ultrastructural and microanalytical investigations. IHC demonstrated the expression of markers of epithelial-to-mesenchymal transition (VIM), bone mineralization, and osteoblastic differentiation (BMP-2, PTX-3, RUNX2, RANKL, and VDR) in prostate lesions characterized by the presence of calcium-phosphate microcalcifications and high metastatic potential. Ultrastructural studies revealed the presence of prostate cancer cells with osteoblast phenotype close to microcalcifications. Noteworthy, PET/CT analysis showed higher uptake of 18F-choline in BM+ lesions with high positivity (≥300/500 cells) for RUNX2 and/or RANKL immunostaining. Although these data require further investigations about the molecular mechanisms of POLCs generation and role in bone metastasis, our study can open new and interesting prospective in the management of prostate cancer patients. The presence of POLCs along with prostate microcalcifications may become negative prognostic markers of the occurrence of bone metastases.

Functional Expression of Organic Anion Transporting Polypeptide 1a4 Is Regulated by Transforming Growth Factor-β/Activin Receptor-like Kinase 1 Signaling at the Blood-Brain Barrier

Central nervous system (CNS) drug delivery can be achieved by targeting drug uptake transporters such as Oatp1a4. In fact, many drugs that can improve neurologic outcomes in CNS diseases [3-hydroxy-3-methylglutaryl-CoA reductase inhibitors (i.e., statins)] are organic anion transporting polypeptide (OATP) transport substrates. To date, transport properties and regulatory mechanisms of Oatp1a4 at the blood-brain barrier (BBB) have not been rigorously studied. Such knowledge is critical to develop Oatp1a4 for optimization of CNS drug delivery and for improved treatment of neurological diseases. Our laboratory has demonstrated that the transforming growth factor-β (TGF-β)/activin receptor-like kinase 1 (ALK1) signaling agonist bone morphogenetic protein 9 (BMP-9) increases functional expression of Oatp1a4 in rat brain microvessels. Here, we expand on this work and show that BMP-9 treatment increases blood-to-brain transport and brain exposure of established OATP transport substrates (i.e., taurocholate, atorvastatin, and pravastatin). We also demonstrate that BMP-9 activates the TGF-β/ALK1 pathway in brain microvessels as indicated by increased nuclear translocation of specific Smad proteins associated with signaling mediated by the ALK1 receptor (i.e., pSmad1/5/8). Furthermore, we report that an activated Smad protein complex comprised of phosphorylated Smad1/5/8 and Smad4 is formed following BMP-9 treatment and binds to the promoter of the Slco1a4 gene (i.e., the gene that encodes Oatp1a4). This signaling mechanism causes increased expression of Slco1a4 mRNA. Overall, this study provides evidence that Oatp1a4 transport activity at the BBB is directly regulated by TGF-β/ALK1 signaling and indicates that this pathway can be targeted for control of CNS delivery of OATP substrate drugs.

Impact of selective anti-BMP9 treatment on tumor cells and tumor angiogenesis

The role of bone morphogenic protein 9 (BMP9) signaling in angiogenesis has been controversial, with a number of studies showing that it acts either as a pro-angiogenic or, conversely, as an anti-angiogenic factor in a context-dependent manner. Notably, BMP9 was also reported to function in both pro- or anti-tumorigenic roles during tumor progression. It has therefore remained unclear, whether selective BMP9 inhibition is a useful target for antibody therapy of cancer. To shed light on these questions, we characterized BMP9 expression in plasma of patients with different cancer indications and found elevated levels of pro-domains and precursor BMP9 with a strong response in renal cell carcinoma (RCC). These studies prompted us to evaluate the potential of selective anti-BMP9 cancer therapy in RCC. We generated a novel monoclonal therapeutic antibody candidate, mAb BMP9-0093, that selectively targets all different BMP9 variants but does not bind to the closest homolog BMP10. In vitro, mAb BMP9-0093 treatment inhibited signaling, endothelin-1 (ET-1) production and spreading of endothelial cells and restored BMP9-induced decrease in pericyte migration and attachment. Furthermore, BMP9-mediated epithelial-mesenchymal transition of renal cell carcinoma cells was reversed by mAb BMP9-0093 treatment in vitro. In vivo, mAb BMP9-0093 showed significant anti-tumor activity that was associated with an increase in apoptosis as well as a decrease in tumor cell proliferation and ET-1 release. Furthermore, mAb BMP9-0093 induced mural cell coverage of endothelial cells, which was corroborated by a reduction in vascular permeability, demonstrated by a diminished penetration of omalizumab-Alexa 647 into tumor tissue. Our findings provide new evidence for a better understanding of BMP9 contribution in tumor progression and angiogenesis that may result in the development of effective targeted therapeutic interventions.

Bone morphogenetic protein-9 increases the functional expression of organic anion transporting polypeptide 1a4 at the blood-brain barrier via the activin receptor-like kinase-1 receptor

Targeting uptake transporters such as organic anion transporting polypeptide 1a4 (Oatp1a4) at the blood-brain barrier (BBB) can facilitate central nervous system (CNS) drug delivery. Effective blood-to-brain drug transport via this strategy requires characterization of mechanisms that modulate BBB transporter expression and/or activity. Here, we show that activation of activin receptor-like kinase (ALK)-1 using bone morphogenetic protein (BMP)-9 increases Oatp1a4 protein expression in rat brain microvessels in vivo. These data indicate that targeting ALK1 signaling with BMP-9 modulates BBB Oatp1a4 expression, presenting a unique opportunity to optimize drug delivery and improve pharmacotherapy for CNS diseases.

Bone morphogenetic protein 9 (BMP9) and BMP10 enhance tumor necrosis factor-α-induced monocyte recruitment to the vascular endothelium mainly via activin receptor-like kinase 2

Bone morphogenetic proteins 9 and 10 (BMP9/BMP10) are circulating cytokines with important roles in endothelial homeostasis. The aim of this study was to investigate the roles of BMP9 and BMP10 in mediating monocyte-endothelial interactions using an in vitro flow adhesion assay. Herein, we report that whereas BMP9/BMP10 alone had no effect on monocyte recruitment, at higher concentrations both cytokines synergized with tumor necrosis factor-α (TNFα) to increase recruitment to the vascular endothelium. The BMP9/BMP10-mediated increase in monocyte recruitment in the presence of TNFα was associated with up-regulated expression levels of E-selectin, vascular cell adhesion molecule (VCAM-1), and intercellular adhesion molecule 1 (ICAM-1) on endothelial cells. Using siRNAs to type I and II BMP receptors and the signaling intermediaries (Smads), we demonstrated a key role for ALK2 in the BMP9/BMP10-induced surface expression of E-selectin, and both ALK1 and ALK2 in the up-regulation of VCAM-1 and ICAM-1. The type II receptors, BMPR-II and ACTR-IIA were both required for this response, as was Smad1/5. The up-regulation of cell surface adhesion molecules by BMP9/10 in the presence of TNFα was inhibited by LDN193189, which inhibits ALK2 but not ALK1. Furthermore, LDN193189 inhibited monocyte recruitment induced by TNFα and BMP9/10. BMP9/10 increased basal IκBα protein expression, but did not alter p65/RelA levels. Our findings suggest that higher concentrations of BMP9/BMP10 synergize with TNFα to induce the up-regulation of endothelial selectins and adhesion molecules, ultimately resulting in increased monocyte recruitment to the vascular endothelium. This process is mediated mainly via the ALK2 type I receptor, BMPR-II/ACTR-IIA type II receptors, and downstream Smad1/5 signaling.

BMP-9 interferes with liver regeneration and promotes liver fibrosis

OBJECTIVE

Bone morphogenetic protein (BMP)-9, a member of the transforming growth factor-β family of cytokines, is constitutively produced in the liver. Systemic levels act on many organs and tissues including bone and endothelium, but little is known about its hepatic functions in health and disease.

DESIGN

Levels of BMP-9 and its receptors were analysed in primary liver cells. Direct effects of BMP-9 on hepatic stellate cells (HSCs) and hepatocytes were studied in vitro, and the role of BMP-9 was examined in acute and chronic liver injury models in mice.

RESULTS

Quiescent and activated HSCs were identified as major BMP-9 producing liver cell type. BMP-9 stimulation of cultured hepatocytes inhibited proliferation, epithelial to mesenchymal transition and preserved expression of important metabolic enzymes such as cytochrome P450. Acute liver injury caused by partial hepatectomy or single injections of carbon tetrachloride (CCl₄) or lipopolysaccharide (LPS) into mice resulted in transient downregulation of hepatic BMP-9 mRNA expression. Correspondingly, LPS stimulation led to downregulation of BMP-9 expression in cultured HSCs. Application of BMP-9 after partial hepatectomy significantly enhanced liver damage and disturbed the proliferative response. Chronic liver damage in BMP-9-deficient mice or in mice adenovirally overexpressing the selective BMP-9 antagonist activin-like kinase 1-Fc resulted in reduced deposition of collagen and subsequent fibrosis.

CONCLUSIONS

Constitutive expression of low levels of BMP-9 stabilises hepatocyte function in the healthy liver. Upon HSC activation, endogenous BMP-9 levels increase in vitro and in vivo and high levels of BMP-9 cause enhanced damage upon acute or chronic injury.

Functional Expression of P-glycoprotein and Organic Anion Transporting Polypeptides at the Blood-Brain Barrier: Understanding Transport Mechanisms for Improved CNS Drug Delivery?

Drug delivery to the central nervous system (CNS) is greatly limited by the blood-brain barrier (BBB). Physical and biochemical properties of the BBB have rendered treatment of CNS diseases, including those with a hypoxia/reoxygenation (H/R) component, extremely difficult. Targeting endogenous BBB transporters from the ATP-binding cassette (ABC) superfamily (i.e., P-glycoprotein (P-gp)) or from the solute carrier (SLC) family (i.e., organic anion transporting polypeptides (OATPs in humans; Oatps in rodents)) has been suggested as a strategy that can improve delivery of drugs to the brain. With respect to P-gp, direct pharmacological inhibition using small molecules or selective regulation by targeting intracellular signaling pathways has been explored. These approaches have been largely unsuccessful due to toxicity issues and unpredictable pharmacokinetics. Therefore, our laboratory has proposed that optimization of CNS drug delivery, particularly for treatment of diseases with an H/R component, can be achieved by targeting Oatp isoforms at the BBB. As the major drug transporting Oatp isoform, Oatp1a4 has demonstrated blood-to-brain transport of substrate drugs with neuroprotective properties. Furthermore, our laboratory has shown that targeting Oatp1a4 regulation (i.e., TGF-β signaling mediated via the ALK-1 and ALK-5 transmembrane receptors) represents an opportunity to control Oatp1a4 functional expression for the purpose of delivering therapeutics to the CNS. In this review, we will discuss limitations of targeting P-gp-mediated transport activity and the advantages of targeting Oatp-mediated transport. Through this discussion, we will also provide critical information on novel approaches to improve CNS drug delivery by targeting endogenous uptake transporters expressed at the BBB.

Docosahexaenoic acid blocks progression of western diet-induced nonalcoholic steatohepatitis in obese Ldlr-/- mice

Background

Nonalcoholic fatty liver disease (NAFLD) is a major public health concern in western societies. Nonalcoholic steatohepatitis (NASH), the progressive form of NAFLD, is characterized by hepatic steatosis, inflammation, oxidative stress and fibrosis. NASH is a risk factor for cirrhosis and hepatocellular carcinoma. NASH is predicted to be the leading cause of liver transplants by 2020. Despite this growing public health concern, there remain no Food and Drug Administration (FDA) approved NASH treatments. Using Ldlr^-/- mice as a preclinical model of western diet (WD)-induced NASH, we previously established that dietary supplementation with docosahexaenoic acid (DHA, 22:6,ω3) attenuated WD-induced NASH in a prevention study. Herein, we evaluated the capacity of DHA supplementation of the WD and a low fat diet to fully reverse NASH in mice with pre-existing disease.

Methods

Ldlr^-/- mice fed the WD for 22 wks developed metabolic syndrome (MetS) and a severe NASH phenotype, including obesity, dyslipidemia, hyperglycemia, hepatic steatosis, inflammation, fibrosis and low hepatic polyunsaturated fatty acid (PUFA) content. These mice were randomized to 5 groups: a baseline group (WDB, sacrificed at 22 wks) and 4 treatments: 1) WD + olive oil (WDO); 2) WD + DHA (WDD); 3) returned to chow + olive oil (WDChO); or 4) returned to chow + DHA (WDChD). The four treatment groups were maintained on their respective diets for 8 wks. An additional group was maintained on standard laboratory chow (Reference Diet, RD) for the 30-wk duration of the study.

Results

When compared to the WDB group, the WDO group displayed increased hepatic expression of genes linked to inflammation (Opn, Il1rn, Gdf15), hepatic fibrosis (collagen staining, Col1A1, Thbs2, Lox) reflecting disease progression. Mice in the WDD group, in contrast, had increased hepatic C_20-22 ω3 PUFA and no evidence of NASH progression. MetS and NASH markers in the WDChO or WDChD groups were significantly attenuated and marginally different from the RD group, reflecting disease remission.

Conclusion

While these studies establish that DHA supplementation of the WD blocks WD-induced NASH progression, DHA alone does not promote full remission of diet-induced MetS or NASH.

Identification of bone morphogenetic protein 9 (BMP9) as a novel profibrotic factor in vitro

Upregulated synthesis of extracellular matrix (ECM) proteins by myofibroblasts is a common phenomenon in the development of fibrosis. Although the role of TGF-β in fibrosis development has been extensively studied, the involvement of other members of this superfamily of cytokines, the bone morphogenetic proteins (BMPs) in organ fibrosis has given contradictory results. BMP9 is the main ligand for activin receptor-like kinase-1 (ALK1) TGF-β1 type I receptor and its effect on fibrosis development is unknown. Our purpose was to study the effect of BMP9 in ECM protein synthesis in fibroblasts, as well as the involved receptors and signaling pathways. In cultured mice fibroblasts, BMP9 induces an increase in collagen, fibronectin and connective tissue growth factor expression, associated with Smad1/5/8, Smad2/3 and Erk1/2 activation. ALK5 inhibition with SB431542 or ALK1/2/3/6 with dorsomorphin-1, inhibition of Smad3 activation with SIS3, and inhibition of the MAPK/Erk1/2 with U0126, demonstrates the involvement of these pathways in BMP9-induced ECM synthesis in MEFs. Whereas BMP9 induced Smad1/5/8 phosphorylation through ALK1, it also induces Smad2/3 phosphorylation through ALK5 but only in the presence of ALK1. Summarizing, this is the first study that accurately identifies BMP9 as a profibrotic factor in fibroblasts that promotes ECM protein expression through ALK1 and ALK5 receptors.

β-ionone modulates the expression of miRNAs and genes involved in the metastatic phenotype of microdissected persistent preneoplastic lesions in rats submitted to hepatocarcinogenesis

MicroRNAs (miRNAs) are post-transcriptional gene expression regulators which expression is frequently altered in hepatocellular carcinoma (HCC). β-ionone (βI) is noted for its ability to inhibit persistent preneoplastic lesions (pPNLs) in liver rats. We evaluated the expression of miRNAs involved in carcinogenesis and possible targets modulated by βI, in pPNLs and surrounding of microdissected tissues. Rats subjected to resistant hepatocyte model were treated during promotion stage with βI (16 mg/100 g body weight) or corn oil (CO; 0.25 mL/100 g body weight; controls). Five animals receive no treatment (NT). In CO group, 38 and 29 miRNAs showed reduced expression relative to NT (P < 0.05) in pPNLs and surrounding, respectively. No miRNAs showed increased expression in surrounding of the CO compared to NT group; however, 30 miRNAs showed increased expression (P ≤ 0.05) in pPNLs of the CO group. There was no difference between βI and CO groups (P > 0.05) in the expression of miRNAs in surrounding. In pPNLs βI increased expression of miR-122 and miR-34a (P ≤ 0.05) and reduced of Igf2 (P ≤ 0.05), target of the latter, compared to CO. Additionally, βI decreased the expression of miR-181c and its target Gdf2 (P ≤ 0.05). βI reduced the expression of miR-181b and miR-708 (P ≤ 0.05) and increased the expression of their respective target mRNAs Timp3 and Mtss1 (P ≤ 0.05), relative to CO group. Modulation of miRNAs target genes by βI was confirmed in vitro. βI is a promising chemopreventive agent in the initial stages of hepatocarcinogenesis, as it modulates the expression of the miRNAs and target genes that can alter the metastatic phenotype of HCC. © 2016 Wiley Periodicals, Inc.

The rationale for targeting TGF-β in chronic liver diseases

BACKGROUND

Transforming growth factor (TGF)-β is a pluripotent cytokine that displays several tissue-specific biological activities. In the liver, TGF-β is considered a fundamental molecule, controlling organ size and growth by limiting hepatocyte proliferation. It is involved in fibrogenesis and, therefore, in worsening liver damage, as well as in triggering the development of hepatocellular carcinoma (HCC). TGF-β is known to act as an oncosuppressor and also as a tumour promoter in HCC, but its role is still unclear.

DESIGN

In this review, we discuss the potential role of TGF-β in regulating the tumoural progression of HCC, and therefore the rationale for targeting this molecule in patients with HCC.

RESULTS

A considerable amount of experimental preclinical evidence suggests that TGF-β is a promising druggable target in patients with HCC. To support this hypothesis, a phase II clinical trial is currently ongoing using a TGF-β pathway inhibitor, and results will soon be available.

CONCLUSIONS

The identification of new TGF-β related biomarkers will help to select those patients most likely to benefit from therapy aimed at inhibiting the TGF-β pathway. New formulations that may provide a more controlled and sustained delivery of the drug will improve the therapeutic success of such treatments.

Genome-wide CpG island methylation and intergenic demethylation propensities vary among different tumor sites

The epigenetic landscape of cancer includes both focal hypermethylation and broader hypomethylation in a genome-wide manner. By means of a comprehensive genomic analysis on 6637 tissues of 21 tumor types, we here show that the degrees of overall methylation in CpG island (CGI) and demethylation in intergenic regions, defined as ‘backbone’, largely vary among different tumors. Depending on tumor type, both CGI methylation and backbone demethylation are often associated with clinical, epidemiological and biological features such as age, sex, smoking history, anatomic location, histological type and grade, stage, molecular subtype and biological pathways. We found connections between CGI methylation and hypermutability, microsatellite instability, IDH1 mutation, 19p gain and polycomb features, and backbone demethylation with chromosomal instability, NSD1 and TP53 mutations, 5q and 19p loss and long repressive domains. These broad epigenetic patterns add a new dimension to our understanding of tumor biology and its clinical implications.

Hypothesis: Neuroendocrine Mechanisms (Hypothalamus-Growth Hormone-STAT5 Axis) Contribute to Sex Bias in Pulmonary Hypertension

Pulmonary hypertension (PH) is a disease with high morbidity and mortality. The prevalence of idiopathic pulmonary arterial hypertension (IPAH) and hereditary pulmonary arterial hypertension (HPAH) is approximately two- to four-fold higher in women than in men. Paradoxically, there is an opposite male bias in typical rodent models of PH (chronic hypoxia or monocrotaline); in these models, administration of estrogenic compounds (for example, estradiol-17β [E2]) is protective. Further complexities are observed in humans ingesting anorexigens (female bias) and in rodent models, such as after hypoxia plus SU5416/Sugen (little sex bias) or involving serotonin transporter overexpression or dexfenfluramine administration (female bias). These complexities in sex bias in PH remain incompletely understood. We recently discovered that conditional deletion of signal transducer and activator of transcription 5a/b (STAT5a/b) in vascular smooth muscle cells abrogated the male bias in PH in hypoxic mice and that late-stage obliterative lesions in patients of both sexes with IPAH and HPAH showed reduced STAT5a/b, reduced Tyr-P-STAT5 and reduced B-cell lymphoma 6 protein (BCL6). In trying to understand the significance of these observations, we realized that there existed a well-characterized E2-sensitive central neuroendocrine mechanism of sex bias, studied over the last 40 years, that, at its peripheral end, culminated in species-specific male ("pulsatile") versus female ("more continuous") temporal patterns of circulating growth hormone (GH) levels leading to male versus female patterned activation of STAT5a/b in peripheral tissues and thus sex-biased expression of hundreds of genes. In this report, we consider the contribution of this neuroendocrine mechanism (hypothalamus-GH-STAT5) in the generation of sex bias in different PH situations.

Regulatory role of BMP-9 in steroidogenesis by rat ovarian granulosa cells

BMPs expressed in the ovary differentially regulate steroidogenesis by granulosa cells. BMP-9, a circulating BMP, is associated with cell proliferation, apoptosis and differentiation in various tissues. However, the effects of BMP-9 on ovarian function have yet to be elucidated. Here we investigated BMP-9 actions on steroidogenesis using rat primary granulosa cells. BMP-9 potently suppressed FSH-induced progesterone production, whereas it did not affect FSH-induced estradiol production by granulosa cells. The effects of BMP-9 on FSH-induced steroidogenesis were not influenced by the presence of oocytes. FSH-induced cAMP synthesis and FSH-induced mRNA expression of steroidogenic factors, including StAR, P450scc, 3βHSD2 and FSHR, were suppressed by treatment with BMP-9. BMP-9 mRNA expression was detected in granulosa cells but not in oocytes. BMP-9 readily activated Smad1/5/8 phosphorylation and Id-1 transcription in granulosa cells. Analysis using ALK inhibitors indicated that BMP-9 actions were mediated via type-I receptors other than ALK-2, -3 and -6. Furthermore, experiments using extracellular domains (ECDs) for BMP type-I and -II receptor constructs revealed that the effects of BMP-9 were reversed by ECDs for ALK-1 and BMPRII. Thus, the functional receptors for BMP-9 in granulosa cells were most likely to be the complex of ALK-1 and BMPRII. Collectively, the results of the present study showed that BMP-9 can affect luteinization and that there are two possible sources of BMP-9, serum and granulosa cells in the ovary.

Potential roles of BMP9 in liver fibrosis

Liver fibrosis is a common phenomenon that is associated with several pathologies and is characterized by excessive extracellular matrix deposition that leads to progressive liver dysfunction. Bone morphogenetic protein 9 (BMP9) is the most recently discovered member of the BMP family. BMP9 bound with high affinity to activin receptor-like kinase 1 (ALK1) and endoglin in non-parenchymal liver cells. In addition, BMP9 activated Smad1/Smad5/Smad8 and induced the expression of the target genes inhibitor of differentiation 1 (Id1), hepcidin, Snail and the co-receptor endoglin in liver cells. Although the role of BMP9 in liver fibrosis is currently poorly understood, the presence of BMP9-activated proteins and its target genes have been reported to be associated with liver fibrosis development. This review summarizes the indirect connection between BMP9 and liver fibrosis, with a focus on the BMP9 signaling pathway members ALK1, endoglin, Id1, hepcidin and Snail. The observations on the role of BMP9 in regulating liver fibrosis may help in understanding the pathology mechanisms of liver disease. Furthermore, BMP9 could be served as a potent biomarker and the target of potential therapeutic drugs to treat hepatocytes fibrosis.