Adenovirus-mediated expression of BMP-7 suppresses the development of liver fibrosis in rats

The miR-3074/BMP7 axis regulates TGF-β-caused activation of hepatic stellate cells in vitro and CCl4-caused murine liver fibrosis in vivo

Continuously progressive hepatic fibrosis might cause chronic liver diseases, resulting in hepatic failure. The activation of hepatic stellate cells (HSCs) residing in the liver might induce and influence hepatic fibrosis. In the present study, microRNA 3074 (miR-3074) was found increased within transforming growth factor-β (TGF-β)-activated HSCs and enriched within the TGF-β signaling. In activated HSCs by TGF-β, miR-3074 overexpression aggravated TGF-β-induced fibrotic changes, whereas miR-3074 inhibition exerted opposite effects. miR-3074 directly targeted bone morphogenetic protein 7 (BMP7) and inhibited BMP7 expression. Under TGF-β induction, overexpressed BMP7 notably attenuated the promotive roles of miR-3074 overexpression in TGF-β-activated HSCs. Within carbon tetrachloride (CCl4)-caused liver fibrosis murine model, miR-3074 agomir administration promoted, while LV-BMP7 administration alleviated CCl4-induced fibrotic changes; LV-BMP7 significantly attenuated the effects of miR-3074 agomir. Lastly, mmu-miR-3074 also targeted mouse BMP7 and inhibited mouse BMP7 expression. In conclusion, the miR-3074/BMP7 axis regulates TGF-β-caused activation of HSCs in vitro and CCl4-caused murine liver fibrosis in vivo. BMP7-mediated Smad1/5/8 activation might be involved.

BMP2 restores erectile dysfunction through neurovascular regeneration and fibrosis reduction in diabetic mice

BACKGROUND

The odds of erectile dysfunction are three times more prevalent in diabetes. Severe peripheral vascular and neural damage in diabetic patients responds poorly to phosphodiesterase-5 (PDE5) inhibitors. However, bone morphogenetic protein 2 is known to be involved in angiogenesis.

OBJECTIVES

To assess the efficacy of bone morphogenetic protein 2 in stimulating angiogenesis and augmenting nerve regeneration in a mouse model of diabetic-induced erectile dysfunction.

MATERIALS AND METHODS

The induction of diabetes mellitus was performed by streptozotocin (50 mg/kg daily) administered intraperitoneally for 5 successive days to male C57BL/6 mice that were 8 weeks old. Eight weeks post-inductions, animals were allocated to one of five groups: a control group, a streptozotocin-induced diabetic mouse group receiving two intracavernous 20 μL phosphate-buffered saline injections, or one of three bone morphogenetic protein 2 groups administered two injections of bone morphogenetic protein 2 protein (1, 5, or 10 μg) diluted in 20 μL of phosphate-buffered saline within a 3-day interval between the first and second injections. The erectile functions were assessed 2 weeks after phosphate-buffered saline or bone morphogenetic protein 2 protein injections by recording the intracavernous pressure through cavernous nerve electrical stimulation. Angiogenic activities and nerve regenerating effects of bone morphogenetic protein 2 were determined in penile tissues, aorta, vena cava, the main pelvic ganglions, the dorsal roots, and from the primary cultured mouse cavernous endothelial cells. Moreover, fibrosis-related factor protein expressions were evaluated by western blotting.

RESULTS

Erectile function recovery to 81% of the control value in diabetic mice was found with intracavernous bone morphogenetic protein 2 injection (5 μg/20 μL). Pericytes and endothelial cells were extensively restored. It was confirmed that angiogenesis was promoted in the corpus cavernosum of diabetic mice treated with bone morphogenetic protein 2 through increased ex vivo sprouting of aortic rings, vena cava and penile tissues, and migration and tube formation of mouse cavernous endothelial cells. Bone morphogenetic protein 2 protein enhanced cell proliferation and reduced apoptosis in mouse cavernous endothelial cells and penile tissues, and promoted neurite outgrowth in major pelvic ganglia and dorsal root ganglia under high-glucose conditions. Furthermore, bone morphogenetic protein 2 suppressed fibrosis by reducing mouse cavernous endothelial cell fibronectin, collagen 1, and collagen 4 levels under high-glucose conditions.

CONCLUSION

Bone morphogenetic protein 2 modulates neurovascular regeneration and inhibits fibrosis to revive the mouse erection function in diabetic conditions. Our findings propose that the bone morphogenetic protein 2 protein represents a novel and promising approach to treating diabetes-related erectile dysfunction.

Evaluation of the Reparative Effect of Sinomenine in an Acetaminophen-Induced Liver Injury Model

Due to its rising global prevalence, liver failure treatments are urgently needed. Sinomenine (SIN), an alkaloid from sinomenium acutum, is being studied for its liver-repair properties due to Acetaminophen (APAP) overdose. SIN's effect on APAP-induced hepatotoxicity in rats was examined histologically and biochemically. Three groups of 30 adult male Wistar rats were created: control, APAP-only, and APAP + SIN. Histopathological and biochemical analyses were performed on liver samples after euthanasia. SIN is significantly protected against APAP damage. Compared to APAP-only, SIN reduced cellular injury and preserved hepatocellular architecture. The APAP + SIN Group had significantly lower ALT, MDA, and GSH levels, protecting against hepatocellular damage and oxidative stress. SIN also had dose-dependent antioxidant properties. When examining critical regulatory proteins, SIN partially restored Sirtuin 1 (SIRT1) levels. While BMP-7 levels were unaffected, histopathological evidence and hepatocyte damage percentages supported SIN's liver-restorative effect. SIN protected and repaired rats' livers from APAP-induced liver injury. This study suggests that SIN may treat acute liver damage, warranting further research into its long-term effects, optimal dosage, and clinical applications. These findings aid liver-related emergency department interventions and life-saving treatments.

Long non-coding RNA HOX transcript antisense intergenic RNA depletion protects against alcoholic hepatitis through the microRNA-148a-3p/sphingosine 1-phosphate receptor 1 axis

The aggravating role of long noncoding RNA (lncRNA) HOTAIR has been indicated in liver injury caused by hepatic ischemia/reperfusion. However, under the condition of alcoholic hepatitis (AH), its effects remain unclear. The present study aimed to examine the effect of lncRNA HOTAIR on hepatic stellate cell viability and apoptosis during liver injury caused by AH. In the liver tissues of AH rats, HOTAIR and S1PR1 were overexpressed, and microRNA (miR)-148a-3p was poorly expressed. Loss-of-function assays revealed that silencing of HOTAIR alleviated liver injury in AH by inhibiting the activated phenotype of hepatic stellate cells, inflammation, and fibrosis. Using the bioinformatics databases, dual-luciferase, RIP, and FISH assays, we observed that HOTAIR was mainly localized in the cytoplasm of hepatic stellate cells, and HOTAIR could bind specifically to miR-148a-3p. In addition, miR-148a-3p could target S1PR1 expression. Rescue experiments showed that silencing of miR-148a-3p or overexpression of S1PR1 reversed the alleviating effects of HOTAIR silencing on liver injury. Taken together, our findings revealed that HOTAIR regulates hepatic stellate cell proliferation via the miR-148a-3p/S1PR1 axis in liver injury, which may serve as the basis for developing novel therapeutic strategies to treat AH.

Growth differentiation factor 7 autocrine signaling promotes hepatic progenitor cell expansion in liver fibrosis

BACKGROUND AND AIM

Liver fibrosis is prevalent among chronic diseases of the liver and represents a major health burden worldwide. Growth differentiation factor 7 (GDF7), a member of the TGFβ protein superfamily, has been recently investigated for its role in repair of injured organs, but its role in chronic liver diseases remains unclear. Here, we examined hepatic GDF7 expression and its association with development and progression of human liver fibrosis. Moreover, we determined the source and target cells of GDF7 in the human liver.

METHODS

GDF7 expression was analyzed in fibrotic and healthy human liver tissues by immunohistochemistry and qPCR. Cell-specific accumulation of GDF7 was examined by immunofluorescence through co-staining of cell type-specific markers on formalin-fixed paraffin-embedded human liver tissues. Public single cell RNA sequence databases were analyzed for cell type-specific expression of GDF7. In vitro, human liver organoids and LX-2 hepatic stellate cells (LX-2) were treated with recombinant human GDF7. Human liver organoids were co-cultured with activated LX-2 cells to induce an autocrine signaling circuit of GDF7 in liver organoids.

RESULTS

GDF7 protein levels were elevated in fibrotic liver tissue, mainly detected in hepatocytes and cholangiocytes. In line, GDF7 mRNA was mainly detected in liver parenchymal cells. Expressions of BMPR1A and BMPR2, encoding GDF7 receptors, were readily detected in hepatocytes, cholangiocytes and stellate cells in vivo and in vitro. In vitro, recombinant GDF7 promoted liver organoid growth and enhanced expression of the progenitor cell markers (LGR5, AXIN2), but failed to activate LX-2 cells. Still, activated LX-2 cells induced GDF7 and LGR5 expression in co-cultured human liver organoids.

CONCLUSIONS

Collectively, this study reveals a role of GDF7 in liver fibrosis and suggests a potential pro-regenerative function that can be utilized for amelioration of hepatic fibrosis caused by chronic liver disease.

Bone morphogenetic protein-7 attenuates pancreatic damage under diabetic conditions and prevents progression to diabetic nephropathy via inhibition of ferroptosis

Background

Approximately 30% of diabetic patients develop diabetic nephropathy, a representative microvascular complication. Although the etiological mechanism has not yet been fully elucidated, renal tubular damage by hyperglycemia-induced expression of transforming growth factor-β (TGF-β) is known to be involved. Recently, a new type of cell death by iron metabolism called ferroptosis was reported to be involved in kidney damage in animal models of diabetic nephropathy, which could be induced by TGF-β. Bone morphogenetic protein-7 (BMP7) is a well-known antagonist of TGF-β inhibiting TGF-β-induced fibrosis in many organs. Further, BMP7 has been reported to play a role in the regeneration of pancreatic beta cells in diabetic animal models.

Methods

We used protein transduction domain (PTD)-fused BMP7 in micelles (mPTD-BMP7) for long-lasting in vivo effects and effective in vitro transduction and secretion.

Results

mPTD-BMP7 successfully accelerated the regeneration of diabetic pancreas and impeded progression to diabetic nephropathy. With the administration of mPTD-BMP7, clinical parameters and representative markers of pancreatic damage were alleviated in a mouse model of streptozotocin-induced diabetes. It not only inhibited the downstream genes of TGF-β but also attenuated ferroptosis in the kidney of the diabetic mouse and TGF-β-stimulated rat kidney tubular cells.

Conclusion

BMP7 impedes the progression of diabetic nephropathy by inhibiting the canonical TGF-β pathway, attenuating ferroptosis, and helping regenerate diabetic pancreas.

Insights into bone morphogenetic proteins in cardiovascular diseases

Bone morphogenetic proteins (BMPs) are secretory proteins belonging to the transforming growth factor-β (TGF-β) superfamily. These proteins play important roles in embryogenesis, bone morphogenesis, blood vessel remodeling and the development of various organs. In recent years, as research has progressed, BMPs have been found to be closely related to cardiovascular diseases, especially atherosclerosis, vascular calcification, cardiac remodeling, pulmonary arterial hypertension (PAH) and hereditary hemorrhagic telangiectasia (HHT). In this review, we summarized the potential roles and related mechanisms of the BMP family in the cardiovascular system and focused on atherosclerosis and PAH.

Corneal fibrosis abrogation by a localized AAV-mediated inhibitor of differentiation 3 (Id3) gene therapy in rabbit eyes in vivo

Previously we found that inhibitor of differentiation 3 (Id3) gene, a transcriptional repressor, efficiently inhibits corneal keratocyte differentiation to myofibroblasts in vitro. This study evaluated the potential of adeno-associated virus 5 (AAV5)-mediated Id3 gene therapy to treat corneal scarring using an established rabbit in vivo disease model. Corneal scarring/fibrosis in rabbit eyes was induced by alkali trauma, and 24 h thereafter corneas were administered with either balanced salt solution AAV5-naked vector, or AAV5-Id3 vector (n = 6/group) via an optimized reported method. Therapeutic effects of AAV5-Id3 gene therapy on corneal pathology and ocular health were evaluated with clinical, histological, and molecular techniques. Localized AAV5-Id3 gene therapy significantly inhibited corneal fibrosis/haze clinically from 2.7 to 0.7 on the Fantes scale in live animals (AAV5-naked versus AAV5-Id3; p < 0.001). Furthermore, AAV5-Id3 treatment significantly reduced profibrotic gene mRNA levels: α-smooth muscle actin (α-SMA) (2.8-fold; p < 0.001), fibronectin (3.2-fold; p < 0.001), collagen I (0.8-fold; p < 0.001), and collagen III (1.4-fold; p < 0.001), as well as protein levels of α-SMA (23.8%; p < 0.001) and collagens (1.8-fold; p < 0.001). The anti-fibrotic activity of AAV5-Id3 is attributed to reduced myofibroblast formation by disrupting the binding of E-box proteins to the promoter of α-SMA, a transforming growth factor-β signaling downstream target gene. In conclusion, these results indicate that localized AAV5-Id3 delivery in stroma caused no clinically relevant ocular symptoms or corneal cellular toxicity in the rabbit eyes.

Emerging therapeutic potential of adeno-associated virus-mediated gene therapy in liver fibrosis

Liver fibrosis is a wound-healing response that results from various chronic damages. If the causes of damage are not removed or effective treatments are not given in a timely manner, it will progress to cirrhosis, even liver cancer. Currently, there are no specific medical therapies for liver fibrosis. Adeno-associated virus (AAV)-mediated gene therapy, one of the frontiers of modern medicine, has gained more attention in many fields due to its high safety profile, low immunogenicity, long-term efficacy in mediating gene expression, and increasingly known tropism. Notably, increasing evidence suggests a promising therapeutic potential for AAV-mediated gene therapy in different liver fibrosis models, which helps to correct abnormally changed target genes in the process of fibrosis and improve liver fibrosis at the molecular level. Moreover, the addition of cell-specific promoters to the genome of recombinant AAV helps to limit gene expression in specific cells, thereby producing better therapeutic efficacy in liver fibrosis. However, animal models are considered to be powerless predictive of tissue tropism, immunogenicity, and genotoxic risks in humans. Thus, AAV-mediated gene therapy will face many challenges. This review systemically summarizes the recent advances of AAV-mediated gene therapy in liver fibrosis, especially focusing on cellular and molecular mechanisms of transferred genes, and presents prospective challenges.

Coordinated activation of TGF-β and BMP pathways promotes autophagy and limits liver injury after acetaminophen intoxication

Ligands of the transforming growth factor-β (TGF-β) superfamily, including TGF-βs, activins, and bone morphogenetic proteins (BMPs), have been implicated in hepatic development, homeostasis, and pathophysiology. We explored the mechanisms by which hepatocytes decode and integrate injury-induced signaling from TGF-βs and activins (TGF-β/Activin) and BMPs. We mapped the spatiotemporal patterns of pathway activation during liver injury induced by acetaminophen (APAP) in dual reporter mice carrying a fluorescent reporter of TGF-β/Activin signaling and a fluorescent reporter of BMP signaling. APAP intoxication induced the expression of both reporters in a zone of cells near areas of tissue damage, which showed an increase in autophagy and demarcated the borders between healthy and injured tissues. Inhibition of TGF-β superfamily signaling by overexpressing the inhibitor Smad7 exacerbated acute liver histopathology but eventually accelerated tissue recovery. Transcriptomic analysis identified autophagy as a process stimulated by TGF-β1 and BMP4 in hepatocytes, with Trp53inp2, which encodes a rate-limiting factor for autophagy initiation, as the most highly induced autophagy-related gene. Collectively, these findings illustrate the functional interconnectivity of the TGF-β superfamily signaling system, implicate the coordinated activation of TGF-β/Activin and BMP pathways in balancing tissue reparatory and regenerative processes upon APAP-induced hepatotoxicity, and highlight opportunities and potential risks associated with targeting this signaling system for treating hepatic diseases.

Potential Therapeutic Role of Bone Morphogenic Protein 7 (BMP7) in the Pathogenesis of Graves' Orbitopathy

Purpose

We investigated a role of bone morphogenic protein 7 (BMP7), a member of the TGF-β superfamily on pathogenic mechanism of Graves' orbitopathy (GO). The therapeutic effects of BMP7 on inflammation and fibrosis were evaluated in cultured Graves' orbital fibroblasts.

Methods

Expression of BMP7 was compared in cultured orbital tissue explants from GO (n = 12) and normal control (n = 12) subjects using real-time PCR. Orbital fibroblasts were cultured from orbital connective tissues obtained from GO (n = 3) and normal control patients (n = 3). Cells were pretreated with recombinant human BMP7 (rhBMP7) before stimulation with TGF-β, IL-1β, and TNF-α. Fibrosis-related proteins and inflammatory cytokines were analyzed by Western blotting. The activation of signaling molecules in inflammation and fibrosis was also analyzed.

Results

The expressions of BMP7 mRNA were lower in GO orbital tissues than control. Fibrosis-related proteins, fibronectin, collagen 1α, and α-SMA induced by TGF-β were suppressed by treating rhBMP7, and rhBMP7 upregulated TGF-β induced SMAD1/5/8 protein expression, whereas downregulated SMAD2/3. Increased pro-inflammatory molecules, IL-6, IL-8, and intercellular adhesion molecule-1 (ICAM-1) by IL-1β or TNF-α were blocked by rhBMP7 treatment, and the expression of phosphorylated NFκB and Akt was suppressed by rhBMP7 treatment.

Conclusions

BMP7 transcript levels were downregulated in Graves' orbital tissues. Exogenous BMP7 treatment showed inhibitory effects on the production of profibrotic proteins and proinflammatory cytokines in orbital fibroblasts. Our results provide a molecular basis of BMP7 as a new potential therapeutic agent through the opposing mechanism of profibrotic TGF-β/SMAD signaling and proinflammatory cytokine production.

A micellized bone morphogenetic protein-7 prodrug ameliorates liver fibrosis by suppressing transforming growth factor-β signaling

Bone morphogenetic protein-7 (BMP-7) antagonizes transforming growth factor-β (TGF-β), which is critically involved in liver fibrogenesis. Here, we designed a micelle formulation consisting of a protein transduction domain (PTD) fused BMP-7 polypeptide (mPTD-BMP-7) to enhance endocytic delivery, and investigated its ability to ameliorate liver fibrosis. The mPTD-BMP-7 formulation was efficiently delivered into cells via endocytosis, where it inhibited TGF-β mediated epithelial-mesenchymal transition. After successfully demonstrating delivery of fluorescently labeled mPTD-BMP-7 into the murine liver in vivo, we tested the mPTD-BMP-7 formulation in a murine liver fibrosis model, developed by repeated intraperitoneal injection of hepatotoxic carbon tetrachloride, twice weekly from 4 to 16 weeks. mPTD-BMP-7 effects were tested by injecting the mPTD-BMP-7 formulation (or vehicle control) into the lateral tail at a dose of 50 (n=8) or 500 μg/kg (n=10), also twice per week from 4 to 16 weeks. Vehicle-treated control mice developed fibrous septa surrounding the liver parenchyma and marked portal-to-portal bridging with occasional nodules, whereas mice treated with mPTD-BMP-7 showed only fibrous expansion of some portal areas, with or without short fibrous septa. Using the Ishak scoring system, we found that the fibrotic burden was significantly lower in mPTD-BMP-7 treated mice than in control mice (all P<0.001). Treatment with mPTD-BMP-7 protected tight junctions between hepatocytes and reduced extracellular matrix protein levels. It also significantly decreased mRNA levels of collagen 1A, smooth muscle α-actin, and connective tissue growth factor compared with that in control mice (all P<0.001). Collectively, out results indicate that mPTD-BMP-7, a prodrug formulation of BMP-7, ameliorates liver fibrosis by suppressing the TGF-β signaling pathway in a murine liver fibrosis model.

The miR-23b/27b/24-1 Cluster Inhibits Hepatic Fibrosis by Inactivating Hepatic Stellate Cells

BACKGROUND & AIMS

Hepatic fibrosis is characterized by hepatic stellate cell (HSC) activation and transdifferentiation-mediated extracellular matrix (ECM) deposition, which both contribute to cirrhosis. However, no antifibrotic regimen is available in the clinic. microRNA-23b/27b/24-1 cluster inhibition of transforming growth factor-β (TGF-β) signaling during hepatic development prompted us to explore whether this cluster inhibits HSC activation and hepatic fibrosis.

METHODS

Experimental fibrosis was studied in carbon tetrachloride (CCl₄)-treated C57BL/6 mice. After administration of miR-23b/27b/24-1 lentivirus or vehicle, animals were euthanized for liver histology. In primary rat HSC and HSC-T6, the anti-fibrotic effect of miR-23b/27b/24-1 cluster was furtherly investigated by RNA-sequencing, luciferase reporter assay, western blotting and bioinformatic means.

RESULTS

In this study, we showed that increasing the miR-23b/27b/24-1 level through intravenous delivery of miR-23b/27b/24-1 lentivirus ameliorated mouse hepatic fibrosis. Mechanistically, the miR-23b/27b/24-1 cluster directly targeted messenger RNAs, which reduced the protein expression of 5 secretory profibrotic genes (TGF-β2, Gremlin1, LOX, Itgα2, and Itgα5) in HSCs. Suppression of the TGF-β signaling pathway by down-regulation of TGF-β2, Itgα2, and Itgα5, and activation of the bone morphogenetic protein signaling pathway by inhibition of Gremlin1, decreased extracellular matrix secretion of HSCs. Furthermore, down-regulation of LOX expression softened the ECM. Moreover, a reduction in tissue inhibitors of metalloproteinase 1 expression owing to weakened TGF-β signaling increased ECM degradation.

CONCLUSIONS

Hepatic overexpression of the miR-23b/27b/24-1 cluster blocked hepatic fibrosis and may be a novel therapeutic regimen for patients with hepatic fibrosis.

Insights into Bone Morphogenetic Protein-(BMP-) Signaling in Ocular Lens Biology and Pathology

Bone morphogenetic proteins (BMPs) are a diverse class of growth factors that belong to the transforming growth factor-beta (TGFβ) superfamily. Although originally discovered to possess osteogenic properties, BMPs have since been identified as critical regulators of many biological processes, including cell-fate determination, cell proliferation, differentiation and morphogenesis, throughout the body. In the ocular lens, BMPs are important in orchestrating fundamental developmental processes such as induction of lens morphogenesis, and specialized differentiation of its fiber cells. Moreover, BMPs have been reported to facilitate regeneration of the lens, as well as abrogate pathological processes such as TGFβ-induced epithelial-mesenchymal transition (EMT) and apoptosis. In this review, we summarize recent insights in this topic and discuss the complexities of BMP-signaling including the role of individual BMP ligands, receptors, extracellular antagonists and cross-talk between canonical and non-canonical BMP-signaling cascades in the lens. By understanding the molecular mechanisms underlying BMP activity, we can advance their potential therapeutic role in cataract prevention and lens regeneration.

Extra- and Intra-Cellular Mechanisms of Hepatic Stellate Cell Activation

Hepatic fibrosis is characterized by the pathological accumulation of extracellular matrix (ECM) in the liver resulting from the persistent liver injury and wound-healing reaction induced by various insults. Although hepatic fibrosis is considered reversible after eliminating the cause of injury, chronic injury left unchecked can progress to cirrhosis and liver cancer. A better understanding of the cellular and molecular mechanisms controlling the fibrotic response is needed to develop novel clinical strategies. It is well documented that activated hepatic stellate cells (HSCs) is the most principal cellular players promoting synthesis and deposition of ECM components. In the current review, we discuss pathways of HSC activation, emphasizing emerging extra- and intra-cellular signals that drive this important cellular response to hepatic fibrosis. A number of cell types and external stimuli converge upon HSCs to promote their activation, including hepatocytes, liver sinusoidal endothelial cells, macrophages, cytokines, altered ECM, hepatitis viral infection, enteric dysbiosis, lipid metabolism disorder, exosomes, microRNAs, alcohol, drugs and parasites. We also discuss the emerging signaling pathways and intracellular events that individually or synergistically drive HSC activation, including TGFβ/Smad, Notch, Wnt/β-catenin, Hedgehog and Hippo signaling pathways. These findings will provide novel potential therapeutic targets to arrest or reverse fibrosis and cirrhosis.

Inhibition of TGFβ1 accelerates regeneration of fibrotic rat liver elicited by a novel two-staged hepatectomy

Aims: Emerging evidence is demonstrating that rapid regeneration of remnant liver elicited by associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) may be attenuated in fibrotic livers. However, the molecular mechanisms responsible for this process are largely unknown. It is widely acknowledged that the TGFβ1 signaling axis plays a major role in liver fibrosis. Therefore, the aims of this study were to elucidate the underlying mechanism of liver regeneration during ALPPS with or without fibrosis, specifically focusing on TGFβ1 signaling. Approach: ALPPS was performed in rat models with N-diethylnitrosamine-induced liver fibrosis and no fibrosis. Functional liver remnant regeneration and expression of TGFβ1 were analyzed during the ALPPS procedures. Adeno-associated virus-shTGFβ1 and the small molecule inhibitor LY2157299 (galunisertib) were used separately or in combination to inhibit TGFβ1 signaling in fibrotic rats. Results: Liver regeneration following ALPPS was lower in fibrotic rats than non-fibrotic rats. TGFβ1 was a key mediator of postoperative regeneration in fibrotic liver. Interestingly, AAV-shTGFβ1 accelerated the regeneration of fibrotic functional liver remnant and improved fibrosis, while LY2157299 only enhanced liver regeneration. Moreover, combination treatment elicited a stronger effect. Conclusions: Inhibition of TGFβ1 accelerated regeneration of fibrotic liver, ameliorated liver fibrosis, and improved liver function following ALPPS. Therefore, TGFβ1 is a promising therapeutic target in ALPPS to improve fibrotic liver reserve function and prognosis.

Obesity and Bone Health: A Complex Link

So far, the connections between obesity and skeleton have been extensively explored, but the results are inconsistent. Obesity is thought to affect bone health through a variety of mechanisms, including body weight, fat volume, bone formation/resorption, proinflammatory cytokines together with bone marrow microenvironment. In this review, we will mainly describe the effects of adipokines secreted by white adipose tissue on bone cells, as well as the interaction between brown adipose tissue, bone marrow adipose tissue, and bone metabolism. Meanwhile, this review also reviews the evidence for the effects of adipose tissue and its distribution on bone mass and bone-related diseases, along with the correlation between different populations with obesity and bone health. And we describe changes in bone metabolism in patients with anorexia nervosa or type 2 diabetes. In summary, all of these findings show that the response of skeleton to obesity is complex and depends on diversified factors, such as mechanical loading, obesity type, the location of adipose tissue, gender, age, bone sites, and secreted cytokines, and that these factors may exert a primary function in bone health.

Candidate rejuvenating factor GDF11 and tissue fibrosis: friend or foe?

Growth differentiation factor 11 (GDF11 or bone morphogenetic protein 11, BMP11) belongs to the transforming growth factor-β superfamily and is closely related to other family member-myostatin (also known as GDF8). GDF11 was firstly identified in 2004 due to its ability to rejuvenate the function of multiple organs in old mice. However, in the past few years, the heralded rejuvenating effects of GDF11 have been seriously questioned by many studies that do not support the idea that restoring levels of GDF11 in aging improves overall organ structure and function. Moreover, with increasing controversies, several other studies described the involvement of GDF11 in fibrotic processes in various organ setups. This review paper focuses on the GDF11 and its pro- or anti-fibrotic actions in major organs and tissues, with the goal to summarize our knowledge on its emerging role in regulating the progression of fibrosis in different pathological conditions, and to guide upcoming research efforts.

Emerging therapeutic targets for NASH: key innovations at the preclinical level

Introduction: nonalcoholic steatohepatitis (NASH) is a globally emerging health problem, mainly caused by increasing trends in the prevalence of obesity and metabolic syndrome. Patients with NASH are mainly affected by cardiovascular risk and extrahepatic cancer, but a significant proportion of patients will develop advanced liver disease, eventually resulting in liver failure or hepatocellular carcinoma. Recent research has yielded a better understanding of the underlying mechanisms and potential targetability for drug development.Areas covered: This review focuses on the role of fructose metabolism, de novo lipogenesis (DNL), endoplasmic reticulum (ER) stress, NLRP3 inflammasome, bone morphogenetic protein (BMP) signaling and platelets in the pathophysiology of NASH. We discuss the suitability of these substrates for targeting liver disease as well as cardiovascular health in patients with NASH. A non-systematic literature search was performed on PubMed and ClinicalTrials.gov.Expert opinion: Targeting fructose metabolism, DNL, ER stress, NLRP3 inflammasome, BMP signaling and platelets are promising therapeutic strategies, warranting further preclinical and clinical investigation. The discussed approaches might not only benefit liver-related outcomes but improve cardiovascular disease as well. Amidst the euphoria of advances in drug development for NASH, parallel endeavors need to address the underlying causes of obesity and metabolic syndrome to prevent NASH.

The Role of Bone Morphogenetic Protein 7 (BMP-7) in Inflammation in Heart Diseases

Bone morphogenetic protein-7 is (BMP-7) is a potent anti-inflammatory growth factor belonging to the Transforming Growth Factor Beta (TGF-β) superfamily. It plays an important role in various biological processes, including embryogenesis, hematopoiesis, neurogenesis and skeletal morphogenesis. BMP-7 stimulates the target cells by binding to specific membrane-bound receptor BMPR 2 and transduces signals through mothers against decapentaplegic (Smads) and mitogen activated protein kinase (MAPK) pathways. To date, rhBMP-7 has been used clinically to induce the differentiation of mesenchymal stem cells bordering the bone fracture site into chondrocytes, osteoclasts, the formation of new bone via calcium deposition and to stimulate the repair of bone fracture. However, its use in cardiovascular diseases, such as atherosclerosis, myocardial infarction, and diabetic cardiomyopathy is currently being explored. More importantly, these cardiovascular diseases are associated with inflammation and infiltrated monocytes where BMP-7 has been demonstrated to be a key player in the differentiation of pro-inflammatory monocytes, or M1 macrophages, into anti-inflammatory M2 macrophages, which reduces developed cardiac dysfunction. Therefore, this review focuses on the molecular mechanisms of BMP-7 treatment in cardiovascular disease and its role as an anti-fibrotic, anti-apoptotic and anti-inflammatory growth factor, which emphasizes its potential therapeutic significance in heart diseases.

Mechanisms of liver fibrosis and its role in liver cancer

Hepatic fibrogenesis is a pathophysiological outcome of chronic liver injury hallmarked by excessive accumulation of extracellular matrix proteins. Fibrosis is a dynamic process that involves cross-talk between parenchymal cells (hepatocytes), hepatic stellate cells, sinusoidal endothelial cells and both resident and infiltrating immune cells. In this review, we focus on key cell-types that contribute to liver fibrosis, cytokines, and chemokines influencing this process and what it takes for fibrosis to regress. We discuss how mitochondria and metabolic changes in hepatic stellate cells modulate the fibrogenic process. We also briefly review how the presence of fibrosis affects development of hepatocellular carcinoma.

siRNA- and miRNA-based therapeutics for liver fibrosis

Liver fibrosis is a wound-healing process induced by chronic liver injuries, such as nonalcoholic steatohepatitis, hepatitis, alcohol abuse, and metal poisoning. The accumulation of excessive extracellular matrix (ECM) in the liver is a key characteristic of liver fibrosis. Activated hepatic stellate cells (HSCs) are the major producers of ECM and therefore play irreplaceably important roles during the progression of liver fibrosis. Liver fibrogenesis is highly correlated with the activation of HSCs, which is regulated by numerous profibrotic cytokines. Using RNA interference to downregulate these cytokines in activated HSCs is a promising strategy to reverse liver fibrosis. Meanwhile, microRNAs (miRNAs) have also been exploited for the treatment of liver fibrosis. This review focuses on the current siRNA- and miRNA-based liver fibrosis treatment strategies by targeting activated HSCs in the liver.

Multi-technique comparison of atherogenic and MCD NASH models highlights changes in sphingolipid metabolism. Sci Rep. 2019;9:16810. [PMID: 31728041 PMCID: PMC6856196 DOI: 10.1038/s41598-019-53346-4]

Lipotoxicity is a key player in the pathogenesis of nonalcoholic steatohepatitis (NASH), a progressive subtype of nonalcoholic fatty liver disease (NAFLD). In the present study, we combine histological, transcriptional and lipidomic approaches to dissociate common and specific alterations induced by two classical dietary NASH models (atherogenic (ATH) and methionine/choline deficient (MCD) diet) in C57BL/6J male mice. Despite a similar degree of steatosis, MCD-fed mice showed more pronounced liver damage and a worsened pro-inflammatory and pro-fibrogenic environment than ATH-fed mice. Regarding lipid metabolism, the ATH diet triggered hepatic counter regulatory mechanisms, while the MCD diet worsened liver lipid accumulation by a concomitant increase in lipid import and reduction in lipid export. Liver lipidomics revealed sphingolipid enrichment in both NASH models that was accompanied by an upregulation of the ceramide biosynthesis pathway and a significant rise in dihydroceramide levels. In contrast, the phospholipid composition was not substantially altered by the ATH diet, whereas the livers of MCD-fed mice presented a reduced phosphatidylcholine to phosphatidylethanolamine (PC/PE) ratio and a strong depletion in phospholipids containing the sum of 34-36 carbons in their fatty acid chains. Therefore, the assessment of liver damage at the histological and transcriptional level combined with a lipidomic analysis reveals sphingolipids as shared mediators in liver lipotoxicity and pathogenesis of NASH.

Over-Expression of Inhibitor of Differentiation 2 Attenuates Post-Infarct Cardiac Fibrosis Through Inhibition of TGF-β1/Smad3/HIF-1α/IL-11 Signaling Pathway

Background: Cardiac fibrosis after myocardial infarction mainly causes cardiac diastolic and systolic dysfunction, which results in fatal arrhythmias or even sudden death. Id2, a transcriptional repressor, has been shown to play an important role in the development of fibrosis in various organs, but its effects on cardiac fibrosis remain unclear. This study aimed to explore the effects of Id2 on cardiac fibrosis after myocardial infarction and its possible mechanisms.

Methods: This study was performed in four experimental groups: control group, treatment group (including TGF-β1, hypoxia or MI), treatment+GFP group and treatment+Id2 group. In vitro anoxic and fibrotic models were established by subjecting CFs or NRVMs to a three-gas incubator or TGF-β1, respectively. An animal myocardial infarction model was established by ligating of the left anterior descending coronary artery followed by directly injecting of Id2 adenovirus into the myocardial infarct’s marginal zone.

Results: The results showed that Id2 significantly improved cardiac EF and attenuated cardiac hypertrophy. The mRNA and protein levels of α-SMA, Collagen I, Collagen III, MMP2 and TIMP1 were higher in treatment+Id2 group than those in treatment group as well as in treatment+GFP group both in vivo and in vitro. Immunofluorescence revealed that both α-SMA and vimentin were co-expressed in the treatment group and GFP group, but the co-expression were not detected in the control group and Id2 group. Additionally, our findings illustrated that Id2 had protective effects demonstrated by its ability to inhibit the TGF-β1/Smad3/HIF-1α/IL-11 signaling pathways. Besides, over-expression of Id2 reduced cardiomyocytes apoptosis.

Conclusion: In conclusion, this study demonstrated that over-expression of Id2 preserved cardiac function and ameliorated adverse cardiac remodeling, which might be a promising treatment target for cardiac fibrosis and apoptosis.

The Interactivity between TGFβ and BMP Signaling in Organogenesis, Fibrosis, and Cancer

The Transforming Growth Factor beta (TGFβ) and Bone Morphogenic Protein (BMP) pathways intersect at multiple signaling hubs and cooperatively or counteractively participate to bring about cellular processes which are critical not only for tissue morphogenesis and organogenesis during development, but also for adult tissue homeostasis. The proper functioning of the TGFβ/BMP pathway depends on its communication with other signaling pathways and any deregulation leads to developmental defects or diseases, including fibrosis and cancer. In this review we explore the cellular and physio-pathological contexts in which the synergism or antagonism between the TGFβ and BMP pathways are crucial determinants for the normal developmental processes, as well as the progression of fibrosis and malignancies.

BMP-7/Smads-induced inhibitor of differentiation 2 (Id2) upregulation and Id2/Twist interaction was involved in attenuating diabetic renal tubulointerstitial fibrosis

Renal tubular epithelial-mesenchymal transition (EMT) is the main pathological change in diabetic renal tubulointerstitial fibrosis. Mounting evidence indicates that the inhibitor of differentiation 2 (Id2) protein acts as a negative regulatory factor in organ fibrosis and can inhibit or reverse the process of fibrosis. However, its specific regulatory mechanism is not clear. Diabetes mellitus (DM) rat models were established by injecting rats with streptozotocin and sacrificing them after 16 weeks. Rat renal tubular epithelial cells (NRK-52E) were cultured with normal and high glucose. Immunohistochemical analysis, double immunofluorescence staining, co-immunoprecipitation, Western blot analysis, and real-time polymerase chain reaction were used to determine the expression of Id2, Twist, Smad1/5/8, E-cadherin, α-smooth muscle actin (α-SMA), and collagen Ⅳ. The results showed that bone morphogenetic protein-7 (BMP-7) upregulated the expression of Id2 against high-glucose-induced EMT and extracellular matrix secretion. Moreover, only the simultaneous knockdown of Smad1, Smad5, and Smad8 downregulated the expression of Id2, which was not altered by the individual knockdown of Smad1, Smad5, and Smad8. Basic helix-loop-helix (bHLH) transcription factors were essential for Id2 to regulate the role of downstream target genes, and Twist was a bHLH transcription factor. Therefore, the expression of Twist was examined in this study. Twist was found to be highly expressed in the kidney of DM rats and renal tubular epithelial cells cultured with high glucose. The overexpression of Id2 did not alter the expression of Twist, but the interaction between Id2 and Twist was enhanced. In conclusion, the data showed the specific mechanism underlying Id2 negative regulation in diabetic renal tubulointerstitial fibrosis.

Bone morphogenetic protein-7 represses hepatic stellate cell activation and liver fibrosis via regulation of TGF-β/Smad signaling pathway

BACKGROUND

Liver fibrosis is a refractory disease whose persistence can eventually induce cirrhosis or even liver cancer. Early liver fibrosis is reversible by intervention. As a member of the transforming growth factor-beta (TGF-β) superfamily, bone morphogenetic protein 7 (BMP7) has anti-liver fibrosis functions. However, little is known about BMP7 expression changes and its potential regulatory mechanism as well as the relationship between BMP7 and TGF-β during liver fibrosis. In addition, the mechanism underlying the anti-liver fibrosis function of BMP7 needs to be further explored.

AIM

To investigate changes in the dynamic expression of BMP7 during liver fibrosis, interactions between BMP7 and TGF-β1, and possible mechanisms underlying the anti-liver fibrosis function of BMP7.

METHODS

Changes in BMP7 expression during liver fibrosis and the interaction between BMP7 and TGF-β1 in mice were observed. Exogenous BMP7 was used to treat mouse primary hepatic stellate cells (HSCs) to observe its effect on activation, migration, and proliferation of HSCs and explore the possible mechanism underlying the anti-liver fibrosis function of BMP7. Mice with liver fibrosis received exogenous BMP7 intervention to observe improvement of liver fibrosis by using Masson’s trichrome staining and detecting the expression of the HSC activation indicator alpha-smooth muscle actin (α-SMA) and the collagen formation associated protein type I collagen (Col I). Changes in the dynamic expression of BMP7 during liver fibrosis in the human body were further observed.

RESULTS

In the process of liver fibrosis induced by carbon tetrachloride (CCl₄) in mice, BMP7 protein expression first increased, followed by a decrease; there was a similar trend in the human body. This process was accompanied by a sustained increase in TGF-β1 protein expression. In vitro experiment results showed that TGF-β1 inhibited BMP7 expression in a time- and dose-dependent manner. In contrast, high doses of exogenous BMP7 inhibited TGF-β1-induced activation, migration, and proliferation of HSCs; this inhibitory effect was associated with upregulation of pSmad1/5/8 and downregulation of phosphorylation of Smad3 and p38 by BMP7. In vivo experiment results showed that exogenous BMP7 improved liver fibrosis in mice.

CONCLUSION

During liver fibrosis, BMP7 protein expression first increases and then decreases. This changing trend is associated with inhibition of BMP7 expression by sustained upregulation of TGF-β1 in a time- and dose-dependent manner. Exogenous BMP7 could selectively regulate TGF-β/Smad pathway-associated factors to inhibit activation, migration, and proliferation of HSCs and exert anti-liver fibrosis functions. Exogenous BMP7 has the potential to be used as an anti-liver fibrosis drug.

rSjp40 inhibits activated hepatic stellate cells by promoting nuclear translocation of YB1 and inducing BMP-7/Smad1/5/8 pathway

Background

Activation of hepatic stellate cells is the dominant pathogenic event during the process of liver fibrosis. Bone morphogenic protein (BMP)-7 has recently been identified as an anti-fibrotic factor and leads to phosphorylation of Smad1/5/8 in activated hepatic stellate cells. Its expression can be upregulated by the transcriptional activator, Y-Box protein-1 (YB1). Previous studies have found that the recombinant Schistosoma japonicum protein p40 (rSjp40) can inhibit the activation of hepatic stellate cells, and based on this evidence we attempted to investigate whether or not BMP-7 is involved in rSjp40’s inhibition.

Methods

A human hepatic stellate cell line, the LX-2 cell line, was cultured and treated with rSjp40. The role of BMP-7 was analyzed by Western blot.

Results

Our findings testified that knockdown of BMP-7 impaired rSjp40-induced downregulation of α-SMA and phosphorylation of Smad1/5/8 in LX-2 cells. Furthermore, rSjp40 upregulated expression of BMP-7 at both mRNA and protein levels depending on YB1. Interestingly, YB1 was translocated from the cytoplasm to the nucleus upon treatment of rSjp40.

Conclusions

These results suggest that rSjp40 inhibits the activation of hepatic stellate cells by promoting nuclear translocation of YB1 and inducing BMP-7/Smad1/5/8 pathway, which provide a new clue to guide ongoing research into the anti-fibrosis of rSjp40.

Bone Morphogenetic Protein-6 Inhibits Fibrogenesis in Scleroderma Offering Treatment Options for Fibrotic Skin Disease

BMP6 is known to be crucial for regulating embryonic skin development. This study assessed the role of BMP6 in dermal fibrosis. We detected that BMP6 is significantly increased in skin-derived fibroblasts of patients with localized scleroderma. Moreover, it was shown that BMP6 significantly impacts proliferation, migration, cytoskeletal organization, and collagen expression, as well as activity of the major pro-fibrogenic transcription factor AP-1 in dermal fibroblasts. The importance of BMP6 in dermal fibrosis was further confirmed in an in vivo model of dermal fibrosis in which BMP6-deficient mice showed significantly enhanced fibrosis compared with wild-type mice. Conversely, application of recombinant BMP6 significantly ameliorated dermal fibrosis in this preclinical bleomycin-induced sclerosis model, and herewith provided proof of concept for the successful treatment of this fibrotic skin disease.

Bone morphogenetic protein signaling in inflammation

IMPACT STATEMENT

By compiling findings from recent studies, this review will garner novel insight on the dynamic and complex role of BMP signaling in diseases of inflammation, highlighting the specific roles played by both individual ligands and endogenous antagonists. Ultimately, this summary will help inform the high therapeutic value of targeting this pathway for modulating diseases of inflammation.

Opposing Roles of BMP and TGF-β Signaling Pathways in Pancreatitis: Mechanisms and Therapeutic Implication

Bone morphogenetic proteins (BMPs) comprise a major subgroup of the transforming growth factor (TGF)-β superfamily. They play pivotal roles in embryonic development and tissue homeostasis in adults. Deregulation of BMP and TGF-β signaling contributes to developmental anomalies and multiple diseases. In this mini-review, we focus on BMP signaling in inflammatory disorders of the pancreas, acute and chronic pancreatitis, in contrast to TGF-β signaling. We then discuss molecular mechanisms that interact with and connect between the BMP and TGF-β signaling pathways. Lastly, we review potential implications of these molecular mechanisms for therapeutic development. In summary, BMP signaling pathway plays different roles during pancreatitis disease development, and the antagonism between BMP and TGF-β signaling can be manipulated for therapeutic development against pancreatitis.

MiR-542-3p controls hepatic stellate cell activation and fibrosis via targeting BMP-7

There has been an increasing number of studies about microRNAs as key regulators in the development of hepatic fibrosis. Here, we demonstrate that miR-542-3p can promote hepatic fibrosis by downregulating the expression of bone morphogenetic protein 7 (BMP-7), which is known to antagonize transforming growth factor β1 (TGFβ1)-mediated fibrogenesis effect. The expression of miR-542-3p is increased in activated hepatic stellate cells (HSCs). Downregulation of MiR-542-3p by antisense inhibitors can inhibit HSCs activation markers, including α-smooth muscle actin (α-SMA) and collagen as well as TGFβ signaling pathways. MiR-542-3p was significantly upregulated in carbon tetrachloride (CCl₄ )-induced hepatic fibrosis in mice, and downregulation of miR-542-3p by lentivirus could prevent the development of hepatic fibrosis. In addition, miR-542-3p can directly bind to the 3'-untranslated region of BMP-7 mRNA, indicating that its profibrotic effect appears to be caused by its inhibition of BMP-7. Our results suggest that downregulation of miR-542-3p prevents liver fibrosis both in vitro and in vivo, highlighting its potential as a novel biomarker or therapeutic target for hepatic fibrosis.

A COL1A1 Promoter-Controlled Expression of TGF-β Soluble Receptor Inhibits Hepatic Fibrosis Without Triggering Autoimmune Responses

BACKGROUND

Soluble TGF-β1 type II receptor (sTβRII) via TGF-β1 inhibition could inhibit hepatic fibrosis, but over-dosage triggers autoimmune responses.

AIM

To test whether the use of a TGF-β1-responsive collagen I promoter COL1A1, via generating a feedback loop to TGF-β1 level, could offer accurate control on sTβRII expression.

METHODS

Recombinant adenoviruses with COL1A1 (Ad-COL-sTβRII/Luc) or CMV promoter (Ad-CMV-sTβRII/Luc) were constructed and characterized. Inhibition of TGF-β activity was determined both in vitro and in vivo. Total and bioactive TGF-β, hepatic fibrosis scale, α-SMA, collagen levels, and liver function were determined.

RESULTS

COL1A1, but not CMV, responded to TGF-β1 in vitro. Both in vitro and in vivo, Ad-COL-sTβRII could significantly, but not completely inhibit TGF-β1 activity while Ad-CMV-sTβRII almost completely inhibited TGF-β1 activity. As evidenced by fibrosis scale, α-SMA, and collagen levels in liver tissue, Ad-COL-sTβRII and Ad-CMV-sTβRII had comparable efficacies in treating hepatic fibrosis. Ad-COL-sTβRII was better than Ad-CMV-sTβRII in liver function restore. Ad-CMV-sTβRII, but not Ad-COL-sTβRII, induced high level of anti-dsDNA and anti-Sm antibodies in rats.

CONCLUSIONS

COL1A1 can precisely control sTβRII expression to inhibit excessive bioactive TGF-β level and thus inhibit hepatic fibrosis but without inducing autoimmune responses.

Organ and tissue fibrosis: Molecular signals, cellular mechanisms and translational implications

Fibrosis denotes excessive scarring, which exceeds the normal wound healing response to injury in many tissues. Although the extracellular matrix deposition appears unstructured disrupting the normal tissue architecture and subsequently impairing proper organ function, fibrogenesis is a highly orchestrated process determined by defined sequences of molecular signals and cellular response mechanisms. Persistent injury and parenchymal cell death provokes tissue inflammation, macrophage activation and immune cell infiltration. The release of biologically highly active soluble mediators (alarmins, cytokines, chemokines) lead to the local activation of collagen producing mesenchymal cells such as pericytes, myofibroblasts or Gli1 positive mesenchymal stem cell-like cells, to a transition of various cell types into myofibroblasts as well as to the recruitment of fibroblast precursors. Clinical observations and experimental models highlighted that fibrosis is not a one-way road. Specific mechanistic principles of fibrosis regression involve the resolution of chronic tissue injury, the shift of inflammatory processes towards recovery, deactivation of myofibroblasts and finally fibrolysis of excess matrix scaffold. The thorough understanding of common principles of fibrogenic molecular signals and cellular mechanisms in various organs - such as liver, kidney, lung, heart or skin - is the basis for developing improved diagnostics including biomarkers or imaging techniques and novel antifibrotic therapeutics.

Bone Morphogenetic Protein-Based Therapeutic Approaches

Bone morphogenetic proteins (BMPs) constitute the largest subdivision of the transforming growth factor (TGF)-β family of ligands and exert most of their effects through the canonical effectors Smad1, 5, and 8. Appropriate regulation of BMP signaling is critical for the development and homeostasis of numerous human organ systems. Aberrations in BMP pathways or their regulation are increasingly associated with diverse human pathologies, and there is an urgent and growing need to develop effective approaches to modulate BMP signaling in the clinic. In this review, we provide a wide perspective on diseases and/or conditions associated with dysregulated BMP signal transduction, outline the current strategies available to modulate BMP pathways, highlight emerging second-generation technologies, and postulate prospective avenues for future investigation.

BMP7 regulates lung fibroblast proliferation in newborn rats with bronchopulmonary dysplasia

The present study investigated the expression of bone morphogenetic protein (BMP) 7 in a newborn rat model of bronchopulmonary dysplasia (BPD) and the biological effects of BMP7 on newborn rat lung fibroblast (LF) cells. For this purpose, a total of 196 newborn rats were randomly and equally assigned to a model group and a control group. Lung tissue was collected at days 3, 7, 14 and 21 for histological analysis. The location and expression of BMP7 was examined by immunohistochemical staining and reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) analysis. A total of 38 full‑term newborn rats on the day of birth were sacrificed and LF cells were isolated and treated with BMP7. The biological effects of BMP7 on LF cells were assessed by cell proliferation and cell cycle analysis. The findings demonstrated that abnormal alveolar development due to BPD was gradually intensified in the model group over time. Immunohistochemical staining revealed that the location of BMP7 in lung tissue was altered. Immunohistochemistry and RT‑qPCR assays demonstrated a gradual decrease in BMP7 expression in the model group induced by hyperoxia. MTT assays demonstrated that BMP7 inhibited LF cells and the inhibitory effect was dose‑dependent and time‑dependent. Flow cytometry revealed that the inhibitory effect of BMP7 in LF cells was causing cell cycle arrest at the G1 phase. The present study demonstrated that BMP7 may serve an important role in alveolar development in a BPD model. BMP7 may be involved in abnormal alveolar development through the regulation of LF proliferation.

Suppression of hepatic stellate cell activation through downregulation of gremlin1 expression by the miR-23b/27b cluster

The imbalance between transforming growth factor β and bone morphogenetic protein 7 signaling pathways is a critical step in promoting hepatic stellate cell activation during hepatic fibrogenesis. Gremlin1 may impair the balance. Something remains unclear about the regulatory mechanisms of gremlin1 action on hepatic stellate cell activation and hepatic fibrosis. In the current study, gremlin1 overexpression promotes activation of hepatic stellate cells. Knockdown of gremlin1 with siRNAs suppresses hepatic stellate cell activation and attenuates hepatic fibrosis in rat model. Our results also show that miR-23b/27b cluster members bind to 3'-untranslated region of gremlin1 resulting in reduction of transforming growth factor β, α-smooth muscle actin and collagenI α1/2 gene expression. Our findings suggest that gremlin1 promotes hepatic stellate cell activation and hepatic fibrogenesis through impairment of the balance between transforming growth factor β and bone morphogenetic protein 7 signaling pathways. The miR-23b/27b cluster suppresses activation of hepatic stellate cells through binding gremlin1 to rectify the imbalance.

Transforming Growth Factor-β and Bone Morphogenetic Protein 2 Regulation of MicroRNA-200 Family in Chronic Pancreatitis

OBJECTIVES

To investigate regulation of microRNA (miR)-200 family (a, b, c, 141, and 429) in chronic pancreatitis (CP). This was accomplished by examining miR-200 family levels in a mouse model in vivo and their regulation in pancreatic cells in vitro.

METHODS

Chronic pancreatitis was induced by cerulein for 4 weeks (50 μg/kg, 5 hourly intraperitoneal injections/day, and 3 days/week). Control mice received normal saline. The pancreata were harvested for fibrosis assessment by Sirius red staining and for miRNA, collagen, and fibronectin levels by quantitative PCR. In vitro, human primary pancreatic stellate cells and human primary pancreatic fibroblast (hPFBs), and rat pancreatic epithelial AR42J cells were treated with vehicle, transforming growth factor (TGF)-β (1 ng/mL), or BMP2 (50 ng/mL) for 24 hours and then harvested for miRNA analysis.

RESULTS

In CP, miR-200s were decreased by 56% to 70% and inversely correlated with pancreatic fibrosis, miR-21, and miR-31 (P < 0.05). In vitro, TGF-β inhibited miR-200b in AR42J cells by 62%, whereas BMP2 increased miR-200b in all 3 cell types in a range of 1.5- to 3.4-fold and inhibited miR-21 in hPFBs by 21% (P < 0.05).

CONCLUSIONS

Both in vivo and in vitro studies suggest an antifibrogenic function of miR-200s in CP. The TGF-β and BMP2 may function through inverse regulation of miR-200b levels.

Resolution of organ fibrosis

Fibrosis is the excessive accumulation of extracellular matrix that often occurs as a wound healing response to repeated or chronic tissue injury, and may lead to the disruption of organ architecture and loss of function. Although fibrosis was previously thought to be irreversible, recent evidence indicates that certain circumstances permit the resolution of fibrosis when the underlying causes of injury are eradicated. The mechanism of fibrosis resolution encompasses degradation of the fibrotic extracellular matrix as well as elimination of fibrogenic myofibroblasts through their adaptation of various cell fates, including apoptosis, senescence, dedifferentiation, and reprogramming. In this Review, we discuss the present knowledge and gaps in our understanding of how matrix degradation is regulated and how myofibroblast cell fates can be manipulated, areas that may identify potential therapeutic approaches for fibrosis.

The Role of Signal Transducer and Activator of Transcription 5 and Transforming Growth Factor-β1 in Hepatic Fibrosis Induced by Chronic Hepatitis C Virus Infection in Egyptian Patients

OBJECTIVE

To investigate the possible role of signal transducer and activator of transcription 5 (STAT5) in the pathogenesis of liver fibrosis in Egyptian patients with chronic hepatitis C (CHC) virus infection and its relation to hepatic stellate cells (HSC).

SUBJECTS AND METHODS

Sixty-five patients (46 males and 19 females) were divided into 4 groups based on the severity of fibrosis as detected by Fibroscan as follows: F1, n = 15; F2, n = 21; F3, n = 13; and F4, n = 16. Twenty age- and gender-matched healthy persons volunteered as controls. The serum levels of STAT5, TGF-β1, α-smooth muscle actin (α-SMA), fasting blood sugar, and fasting insulin, as well as homeostasis model assessment of insulin resistance (HOMA-IR), were determined and compared for all groups. The usefulness of the studied serum biomarkers for predicting liver fibrosis was evaluated using a receiver operating characteristic curve.

RESULTS

Serum levels of STAT5 were significantly lower in patients compared to controls (9.69 ± 5.62 vs. 14.73 ± 6.52, p ≤ 0.001); on the contrary, TGF-β1, α-SMA, and HOMA-IR were significantly higher in patients compared to controls (mean: 1,796.04 vs. 1,636.94; 14.94 vs. 8.1; and 7.91 vs. 4.18; p ≤ 0.01 and 0.001, respectively). TGF-β1 and α-SMA showed a progressive increase with advancing severity of hepatic fibrosis (mean TGF-β1: 2,058.4 in F1-F2 and 1,583.8 in F3-F4, p ≤ 0.04; mean α-SMA: 13.59 in F1-F2 and 16.62 in F3-F4, p ≤ 0.05). STAT5 had a significant negative correlation with TGF-β1 (p ≤ 0.001), while no correlation was detected with α-SMA (p ≤ 0.8).

CONCLUSIONS

STAT5 may play a significant role in hepatic fibrogenesis through the induction of TGF-β1 but not through the activation of hepatic stellate cells.

BMP Signalling at the Crossroad of Liver Fibrosis and Regeneration

Bone Morphogenetic Proteins (BMPs) belong to the Transforming Growth Factor-β (TGF-β) family. Initially identified due to their ability to induce bone formation, they are now known to have multiple functions in a variety of tissues, being critical not only during development for tissue morphogenesis and organogenesis but also during adult tissue homeostasis. This review focus on the liver as a target tissue for BMPs actions, devoting most efforts to summarize our knowledge on their recently recognized and/or emerging roles on regulation of the liver regenerative response to various insults, either acute or chronic and their effects on development and progression of liver fibrosis in different pathological conditions. In an attempt to provide the basis for guiding research efforts in this field both the more solid and more controversial areas of research were highlighted.

Bone Regulates Browning and Energy Metabolism Through Mature Osteoblast/Osteocyte PPARγ Expression

Peroxisome proliferator-activated receptor γ (PPARγ) is a master regulator of energy metabolism. In bone, it is known to regulate osteoblast differentiation and osteoclast activity. Whether PPARγ expression in bone cells, particularly osteocytes, regulates energy metabolism remains unknown. Here, we show that mature osteoblast/osteocyte-specific ablation of PPARγ in mice (Ocy-PPARγ^-/^-) alters body composition with age, namely, to produce less fat and more lean mass, and enhances insulin sensitivity and energy expenditure compared with wild-type mice. In addition, Ocy-PPARγ^-/- mice exhibit more bone density, structure, and strength by uncoupling bone formation from resorption. When challenged with a high-fat diet, Ocy-PPARγ^-/- mice retain glycemic control, with increased browning of the adipose tissue, decreased gluconeogenesis, and less hepatic steatosis. Moreover, these metabolic effects, particularly an increase in fatty acid oxidation, cannot be explained by decarboxylated osteocalcin changes, suggesting existence of other osteokines that are under the control of PPARγ. We further identify bone morphogenetic protein 7 as one of them. Hence, osteocytes coregulate bone and glucose homeostasis through a PPARγ regulatory pathway, and its inhibition could be clinically relevant for the prevention of glucose metabolic disorders.

Bone morphogenetic protein 7 alleviates paraquat-induced pulmonary fibrosis via TGF-β1/Erk1/2 pathway

Bone morphogenetic protein 7 (BMP-7) recently demonstrates an anti-fibrotic effect. To evaluate the role of BMP-7 in paraquat (PQ)-induced pulmonary fibrosis, PQ-exposed mice and lung fibroblasts (MRC-5) were treated with BMP-7. Our results showed that BMP-7 treatment could significantly reduce PQ-induced pulmonary fibrosis, accompanied by downregulation of transforming growth factor (TGF)-β1 and collagen I deposition in mouse lungs. Moreover, PQ-induced inviability, apoptosis, high level of collagen I, as well as phosphorylation of Erk1/2, in MRC-5 cells were significantly inhibited by BMP-7 treatment. These findings indicate BMP-7 alleviates PQ-induced pulmonary fibrosis partly via TGF-β1/Erk1/2 pathway, suggesting a promising therapeutic means for PQ-induced fibrotic lung injury.

Gremlin1 Accelerates Hepatic Stellate Cell Activation Through Upregulation of TGF-Beta Expression

Gremlin1, the antagonist of bone morphogenetic protein-7 and one of the target genes of transforming growth factor (TGF)-β signal pathway, plays an important role in embryonic development and its expression decreases along with aging. To explore the expression of gremlin1 in liver fibrosis and the causal link between gremlin1 and hepatic stellate cell (HSC) activation, we detected the expression of gremlin1 in mice with hepatic fibrosis induced by porcine serum using real time quantitative PCR (RT-qPCR) and immunohistochemical staining. The hepatic fibrosis mice were evaluated by the external feature of the liver, histology, hepatic function, collagen deposition, and the expression of fibrosis-related genes (genes COLIα2 and COLIVα2) in the liver. In the HSC-T6, western blotting was used to analyze the expression of α-smooth muscle actin (α-SMA), COL1α, and TGF-β1 in conditions of overexpression of gremlin1 or gremlin1 being knocked down by specific siRNA, respectively. The results showed that the mRNA expression of the gremlin1 gene was significantly increased consistent with increased expression of COLIα2 and COLIVα2 in the liver tissue of the hepatic fibrosis mice. Increased expression of gremlin1 coincided with the same area of the collagen deposition. Furthermore, the results also showed that the expression of α-SMA, COLIα1, and TGF-β1 was consistent with the expression of gremlin1 not only in the HSC-T6 overexpressing gremlin1 but also in the HSC-T6 that gremlin1 is knocked down by specific siRNA. The findings suggest that gremlin1 might play an important role in the progression of hepatic fibrosis and that it modulates HSC activation.

2'-Hydroxyflavanone ameliorates mesenteric angiogenesis and portal-systemic collaterals in rats with liver fibrosis

BACKGROUND AND AIM

Portal-systemic collaterals lead to dreadful consequences in patients with cirrhosis. Angiogenesis participates in the development of liver fibrosis, hyperdynamic circulation, and portal-systemic collaterals. 2'-Hydroxyflavanone (2'-HF), one of the citrus fruits flavonoids, is known to have antiangiogenesis effect without adverse response. However, the relevant effects in liver fibrosis have not been surveyed.

METHODS

Male Wistar rats received thioacetamide (TAA, 100 mg/kg tiw, i.p.) for 6 weeks to induce liver fibrosis. On the 29th to 42nd day, rats randomly received 2'-HF (100 mg/kg, qod, i.p.) or vehicle (corn oil). On the 43rd day, after hemodynamic measurements, the followings were surveyed: (i) severity of collaterals; (ii) mesenteric angiogenesis; (iii) mesenteric proangiogenic factors protein expressions; (iv) Mesenteric vascular endothelial cells apoptosis; and (v) Mesenteric expressions of proteins regulating apoptosis.

RESULTS

Compared with the vehicle group, 2'-HF did not significantly change body weight, mean arterial pressure, heart rate, and portal pressure in TAA rats. 2'-HF significantly alleviated the severity of collaterals, but the mesenteric phospho-ERK, ERK, phospho-Akt, Akt, COX1, COX2, VEGF, and VEGFR-2 protein expressions were not altered. The apoptotic index of 2'-HF group was significantly higher and the mesenteric protein expressions of pro-apoptotic factors, NFkB 50, NFkB 65, Bax, phospho-p53, 17 kD cleaved caspase 3, and 17 kD casepase 3 were up-regulated.

CONCLUSIONS

2'-HF does not influence the hemodynamics but alleviated the severity of collaterals in rats with liver fibrosis and early portal hypertension. This is, at least partly, attributed to enhanced apoptosis of mesenteric vascular endothelial cells.

The Role of Butylidenephthalide in Targeting the Microenvironment Which Contributes to Liver Fibrosis Amelioration

The treatment of liver fibrosis has clinical limitations because of its multiple etiologies, such as epithelial–mesenchymal transition (EMT) promotion, cell regeneration and remodeling dysfunction, inflammatory cell activation, and scar tissue deposition. These factors might be considered as a new target for the fibrotic microenvironment, leading to increased fibrogenesis and liver fibrosis. Here, we investigate a small molecule named butylidenephthalide (BP) and its multiple effects on liver fibrosis treatment. Thioacetamide was used in vivo to induce chronic liver fibrosis. BP was administered orally in rats for a period of 2 and 4 weeks, which resulted in a significantly reduced fibrosis score (p < 0.05) and (p < 0.001), respectively. The inflammatory reaction of macrophage infiltration were reduced in the administration of BP, which led to the decrease in the transaminase levels. Moreover, we also found liver functions recovering (due to the increased serum albumin and reduced prothrombin time) where liver cells regenerated, which can be seen in the increase of Ki-67 on Oval cell. In addition, the fibrotic scar was also reduced, along with the expression of matrix metalloprotease by hepatic stellate cell. Furthermore, regarding the mechanism/study of EMT reduced by BP, the knockdown of BMP-7, which could reduce α-SMA expression, was mediated by the regulation of TGF-β, which implies its major role on EMT. Finally, in the in vivo study, BP treatment of liver fibrosis was reduced by Bmp7 knockdown in zebrafish, suggesting that BP leads to the reduction of liver fibrosis, which also depends on BMP-7 induction. These results suggest that BP had multiple targets for treating liver fibrosis in the following ways: reduction of EMT, decreasing inflammatory reaction, and liver cell proliferation. This multiple targets approach provided a new mechanism to treat liver injury and fibrosis.

Attenuation of liver fibrosis by herbal compound 861 via upregulation of BMP-7/Smad signaling in the bile duct ligation model rat

Herbal compound 861 (Cpd 861) exerts an anti-fibrotic effect in patients with hepatic fibrosis; however, the anti-fibrotic mechanism has yet to be fully elucidated. The present study aimed to explore the mechanistic basis for the anti-fibrotic effect, with a focus on bone morphogenetic protein 7 (BMP-7)/Smad signaling in a bile duct ligation (BDL)-induced liver fibrosis rat model. Following the induction of hepatic fibrosis, rats induced by BDL were treated with 9 g/kg Cpd 861 daily or an equal volume of saline for 28 days. Serum samples were prepared for monitoring the levels of alanine transaminase, aspartate transaminase and total bilirubin, and direct bilirubin analyses and liver samples were used to investigate gene expression, protein localization and protein expression analysis using real‑time quantitative polymerase chain reaction, immunohistochemistry and western blotting. The results revealed the attenuation of liver fibrosis by Cpd 861 in the histological and biochemical experiments. BMP‑7 and phospho (p)‑Smad1/5/8 were localized predominantly in the cytoplasm of hepatocytes. In comparison with the saline‑treated BDL rats, Cpd 861 markedly upregulated the gene expression of BMP‑7 and Smad5, as well as the protein expression of BMP‑7 and Smad1/5. In addition, p-Smad1/5/8 protein expression was markedly increased by Cpd 861 in the BDL model. These results indicated that Cpd 861 alleviates hepatic fibrosis possibly via the upregulation and activation of BMP-7/Smad signaling in hepatic fibrotic rats.

Intestinal Fibrosis and Liver Fibrosis: Consequences of Chronic Inflammation or Independent Pathophysiology?

Background

Intestinal fibrosis and liver fibrosis represent a significant burden for our patients and health-care systems. Despite the severe clinical problem and the observation that fibrosis is reversible, no specific antifibrotic therapies exist.

Summary

In this review, using an 'East-West' scientific collaboration, we summarize the current knowledge on principal mechanisms shared by intestinal fibrosis and liver fibrosis. We furthermore discuss inflammation as the cause of fibrogenesis in both entities, depict unique features of intestinal and hepatic fibrosis, and provide a future outlook on the development of antifibrotic therapies.

Key Messages

A collaborative effort in the field of fibrosis, covering multiple organ systems, will have the highest chance of leading to the development of a successful antifibrotic intervention.