Bone morphogenetic protein 4 alleviates pulmonary fibrosis by regulating macrophages.

Fibrosis is a pathological change mainly characterized by an increase of fibrous connective tissue and decrease of parenchymal cells. Its continuous progress may lead to the destruction of organ structure and function decline. An excess of alternatively activated M2 macrophages have been considered crucial candidates in the progression of fibrosis. Bone morphogenetic proteins (BMPs), a group of multifunctional growth factors, are essential for organ development and pathophysiological process, however, the roles that BMPs play in innate immune homeostasis in the development of fibrosis and the downstream signals have not been fully explored. In the current study, we firstly found that the expression of BMP4 was significantly down-regulated in human and mouse fibrosis samples. Then we investigated the effects of BMP4 on macrophage polarization in IL-4 environment and related molecular mechanisms, and found that BMP4 caused a decrease in polarized response towards M2, reflected in the expression of the markers Fizz1, Ym1 and Arg1, together with an inhibition in Stat6 phosphorylation. This relied on the Smad1/5/8 signaling, which had a crosstalk with Stat6. Moreover, the in vivo study showed that BMP4 treatment can reduce collagen deposition and delay the development of experimental pulmonary fibrosis in mice by inhibiting M2 macrophages through adoptive transfer experiment. These findings revealed a novel role of BMP4 in regulating macrophages, offering potential strategies for treating pulmonary fibrosis.

Expression pattern of the bone morphogenetic protein-4 and its relationship with inflammation, vascular injury in patients suffered the arterial occlusive diseases. / åŠ¨è„‰é˜»å¡žæ€§ç–¾ç— æ‚£è€ è¡€æµ†éª¨å½¢æ€å‘ç”Ÿè›‹ç™½-4çš„è¡¨è¾¾å˜åŒ–åŠå ¶ä¸Žç‚Žç—‡å’Œè¡€ç®¡æŸä¼¤çš„ç›¸å ³æ€§.

OBJECTIVES: Bone morphogenetic protein-4 (BMP4) has been proved to be an important regulatory factor for the pathological process of atherosclerosis (AS). However, there are few related clinical studies. This study aims to investigate the levels of plasma BMP4 in patients suffering from the arterial occlusive diseases (ACD) characterized by AS, and further to test the relationship between BMP4 and inflammation and vascular injury. METHODS: A total of 38 ACD patients (the ACD group) and 38 healthy people for the physical examination (the control group) were enrolled. The plasma in each subject from both groups was obtained to test the levels of BMP4, tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), IL-10, and vascular endothelial cadherin (VE-cadherin), and the relationship between BMP4 and the detected indicators above were further analyzed. RESULTS: Compared with the control group, the patients in the ACD group displayed significant elevations in the neutrophil to lymphocyte ratio [NLR, 1.63 (1.26, 1.91) vs 3.43 (2.16, 6.61)] and platelet to lymphocyte ratio [PLR, 6.37 (5.26, 7.74) vs 15.79 (7.97, 20.53)], while decrease in the lymphocyte to monocyte ratio [LMR, 5.67 (4.41, 7.14) vs 3.43 (2.07, 3.74)] (all P<0.05). Besides, the ACD patients displayed significant elevations in plasma BMP4 [581.26 (389.85, 735.64) pg/mL vs 653.97(510.95, 890.43) pg/mL], TNF-α [254.16 (182.96, 340.70) pg/mL vs 293.29(238.90, 383.44) pg/mL], and VE-cadherin [1.54 (1.08, 2.13) ng/mL vs 1.85 (1.30, 2.54) ng/mL], and decrease in IL-10 [175.89 (118.39, 219.25) pg/mL vs 135.92 (95.80, 178.04) pg/mL] (all P<0.05). While the levels of IL-1ß remained statistically comparable between the 2 groups (P=0.09). Furthermore, the plasma BMP4 levels were further revealed to be positively correlated with the levels of IL-1ß (r=0.35), TNF-α (r=0.31) and VE-cadherin (r=0.47), while they were negatively correlated with the levels of IL-10 (r=-0.37; all P<0.01). CONCLUSIONS: After ACD occurrence, the patients' plasma concentrations of BMP4 would be upregulated, which may serve as a candidate to indicate the levels of inflammation and vascular injury.

Oncostatin M suppresses bone morphogenetic protein-4-induced osteoprotegerin synthesis in MC3T3-E1 osteoblast-like cells: p70 S6 kinase attenuation.

Evidence is accumulating that osteal macrophages, in addition to bone-resorbing osteoclasts and bone-forming osteoblasts, participate vitally in bone remodeling process. Oncostatin M (OSM), an inflammatory cytokine belonging to interleukin-6 superfamily, is recognized as an essential factor secreted by osteal macrophages to orchestrate bone remodeling. Osteoprotegerin (OPG) produced by osteoblasts regulates osteoclastogenesis. We have reported that bone morphogenetic protein-4 (BMP-4) stimulates OPG synthesis in MC3T3-E1 osteoblast-like cells, and that SMAD1/5/8(9), p38 mitogen-activated protein kinase (MAPK), and p70 S6 kinase are involved in the OPG synthesis. The present study aims to investigate the effect of OSM on the synthesis of OPG stimulated by BMP-4 in osteoblasts. OSM suppressed the release and the mRNA expression of OPG upregulated by BMP-4 in MC3T3-E1 cells. Neither the BMP-4-induced phosphorylation of SMAD1/5/9 nor that of p38 MAPK was affected by OSM. On the other hand, the phosphorylation of p70 S6 kinase stimulated by BMP-4 was considerably suppressed by OSM. These results strongly suggest that OSM suppresses the BMP-4-stimulated OPG synthesis via inhibition of the p70 S6 kinase-mediated pathway in osteoblast-like cells.

Bone morphogenetic protein 4 derived from the cerebrospinal fluid in patients with postherpetic neuralgia induces allodynia via the crosstalk between microglia and astrocyte.

INTRODUCTION: During postherpetic neuralgia (PHN), the cerebral spinal fluid (CSF) possesses the capability to trigger glial activation and inflammation, yet the specific changes in its composition remain unclear. Recent findings from our research indicate elevations of central bone morphogenetic protein 4 (BMP4) during neuropathic pain (NP), serving as an independent modulator of glial cells. Herein, the aim of the present study is to test the CSF-BMP4 expressions and its role in the glial modulation in the process of PHN. METHODS: CSF samples were collected from both PHN patients and non-painful individuals (Control) to assess BMP4 and its antagonist Noggin levels. Besides, intrathecal administration of both CSF types was conducted in normal rats to evaluate the impact on pain behavior, glial activity, and inflammation.; Additionally, both Noggin and STAT3 antagonist-Stattic were employed to treat the PHN-CSF or exogenous BMP4 challenged cultured astrocytes to explore downstream signals. Finally, microglial depletion was performed prior to the PHN-CSF intervention so as to elucidate the microglia-astrocyte crosstalk. RESULTS: BMP4 levels were significantly higher in PHN-CSF compared to Control-CSF (P < 0.001), with a positive correlation with pain duration (P < 0.05, r = 0.502). Comparing with the Control-CSF producing moderate paw withdrawal threshold (PWT) decline and microglial activation, PHN-CSF further exacerbated allodynia and triggered both microglial and astrocytic activation (P < 0.05). Moreover, PHN-CSF rather than Control-CSF evoked microglial proliferation and pro-inflammatory transformation, reinforced iron storage, and activated astrocytes possibly through both SMAD159 and STAT3 signaling, which were all mitigated by the Noggin application (P < 0.05). Next, both Noggin and Stattic effectively attenuated BMP4-induced GFAP and IL-6 upregulation, as well as SMAD159 and STAT3 phosphorylation in the cultured astrocytes (P < 0.05). Finally, microglial depletion diminished PHN-CSF induced astrogliosis, inflammation and endogenous BMP4 expression (P < 0.05). CONCLUSION: Our study highlights the role of CSF-BMP4 elevation in glial activation and allodynia during PHN, suggesting a potential therapeutic avenue for future exploration.

AEBP1 promotes papillary thyroid cancer progression by activating BMP4 signaling.

Papillary thyroid cancer (PTC) is the most prevalent endocrine cancer worldwide. Approximately 30 % of PTC patients will progress into the advanced or metastatic stage and have a relatively poor prognosis. It is well known that epithelial-mesenchymal transition (EMT) plays a pivotal role in thyroid cancer metastasis, resistance to therapy, and recurrence. Clarifying the molecular mechanisms of EMT in PTC progression will help develop the targeted therapy of PTC. The aberrant expression of some transcription factors (TFs) participated in many pathological processes of cancers including EMT. In this study, by performing bioinformatics analysis, adipocyte enhancer-binding protein 1 (AEBP1) was screened as a pivotal TF that promoted EMT and tumor progression in PTC. In vitro experiments indicated that knockout of AEBP1 can inhibit the growth and invasion of PTC cells and reduce the expression of EMT markers including N-cadherin, TWIST1, and ZEB2. In the xenograft model, knockout of AEBP1 inhibited the growth and lung metastasis of PTC cells. By performing RNA-sequencing, dual-luciferase reporter assay, and chromatin immunoprecipitation assay, Bone morphogenetic protein 4 (BMP4) was identified as a downstream target of AEBP1. Over-expression of BMP4 can rescue the inhibitory effects of AEBP1 knockout on the growth, invasion, and EMT phenotype of PTC cells. In conclusion, these findings demonstrated that AEBP1 plays a critical role in PTC progression by regulating BMP4 expression and the AEBP1-BMP4 axis may present novel therapeutic targets for PTC treatment.

Methotrexate inhibits BMP4 and abrogates the hypertrophic chondrocyte phenotype of synovial fibroblasts in juvenile idiopathic arthritis.

BACKGROUND: Juvenile Idiopathic Arthritis (JIA) induces growth disturbances in affected joints. Fibroblast-like synoviocytes (FLS) play a crucial role in JIA pathogenesis. FLS overexpress bone morphogenetic protein 4 (BMP4) and have a chondrocyte-like phenotype. FLS contribute directly to joint growth disturbances through endochondral bone formation. We investigated the ability of methotrexate to inhibit BMP4 expression and alter the hypertrophic chondrocyte-like phenotype of JIA FLS. METHODS: We selected primary cells from three subjects with persistent oligoarticular JIA, three subjects who eventually extended to a polyarticular disease course, which we termed extended-to-be (ETB), and three subjects who had polyarticular arthritis at time of diagnosis. We treated cells with methotrexate and two BMP4 inhibitors: noggin and chordin. We measured protein concentration from three chondrocyte cell markers: collagen II, aggrecan, and collagen X as well as BMP4. RESULTS: ColX, marker of chondrocyte hypertrophy, was significantly increased in polyarticular FLS when compared to both persistent FLS and ETB FLS, making polyarticular FLS the most like hypertrophic chondrocytes. Methotrexate caused significant decreases in BMP4 and ColX expression in persistent, ETB, and polyarticular FLS when compared to respective untreated cells. Ligand-binding BMP4 antagonists, noggin and chordin, caused significant decreases in ColX expression in FLS from all three disease courses and significant increases in collagen II protein, an early chondrocyte marker, when compared to respective untreated cells. CONCLUSIONS: Methotrexate, the first-line therapy in the treatment of JIA, mimics BMP4 antagonists by effectively lowering BMP4 and ColX expression in FLS. Inhibiting FLS from undergoing hypertrophy could prevent these cells from contributing to joint growth disturbances via endochondral bone formation.

Ginsenosides in Panax ginseng Extract Promote Anagen Transition by Suppressing BMP4 Expression and Promote Human Hair Growth by Stimulating Follicle-Cell Proliferation.

Studies showing that Panax ginseng promotes hair growth have largely been conducted using mice; there are few reports on how P. ginseng affects human hair growth. In particular, little is known about its effect on the telogen to anagen transition. To determine the effect of P. ginseng on human hair growth and the transition from the telogen to the anagen phase. The effects of P. ginseng extract (PGE) and the three major ginsenoside components, Rb1, Rg1, and Re, on the proliferation of human dermal papilla cells (DPCs) and human outer root sheath cells (ORSCs) were investigated. The effects of these compounds on the cell expression of bone morphogenetic protein 4 (BMP4), fibroblast growth factor 18 (FGF18) and Noggin were assessed by real-time PCR. The effect of PGE on hair-shaft elongation was determined in a human hair follicle organ-culture system. PGE and the three ginsenosides stimulated the proliferation of DPCs and ORSCs and suppressed BMP4 expression in DPCs but did not affect FGF18 expression in ORSCs and Noggin expression in DPCs. PGE stimulated hair-shaft growth. PGE and the ginsenosides Rb1, Rg1, and Re stimulate the transition from the telogen phase to anagen phase of the hair cycle by suppressing BMP4 expression in DPCs. These compounds might be useful for promoting the growth of human hair.

Bone morphogenetic protein 4 thermosensitive hydrogel inhibits corneal neovascularization by repairing corneal epithelial apical junctional complexes.

Corneal neovascularization (CNV) is a heavy attribute of blinding disease changes. Existing medications need numerous infusions and have a limited absorption. Investigating novel drugs with safety, efficacy, and convenience is crucial. In this study, we developed a bone morphogenetic protein 4 (BMP4)-loaded poloxamer-oxidized sodium alginate (F127-OSA) thermosensitive hydrogel. The 14 % F127-OSA hydrogel transformed from sol to gel at 31-32 °C, which might extend the application period on the ocular surface. The hydrogel's porous structure and uniform dispersion made it possible for drugs to release gradually. We used a suture-induced rat CNV model to investigate the mechanism of CNV inhibition by hydrogel. We discovered that F127-OSA hydrogel loaded with BMP4 could significantly reduce the length and area of CNV, relieve corneal edema, and stop aberrant epithelial cell proliferation. The hydrogel's efficacy was superior to that of the common solvent group. Additionally, BMP4 thermosensitive hydrogel repaired ultrastructure, including microvilli, intercellular junctions, and damaged apical junctional complexes (AJCs), suggesting a potential mechanism by which the hydrogel prevented CNV formation. In conclusion, our investigation demonstrates that F127-OSA thermosensitive hydrogel loaded with BMP4 can repair corneal epithelial AJCs and is a promising novel medication for the treatment of CNV.

BMP4 up-regulated by 630 nm LED irradiation is associated with the amelioration of rheumatoid arthritis.

Rheumatoid arthritis (RA) is caused by inflammatory response of joints with cartilage and damage of synovium and bone erosion. In our previous studies, it has showed that irradiation of 630 nm LED reduce inflammation of synovial fibroblasts and cartilage and bone destruction in RA. However, the key genes and mechanism in ameliorating RA by irradiation of 630 nm LED remains unknown. In this study, human fibroblast-like synoviocytes (FLS) cell line MH7A and primary human RA-FLSs were treated with TNF-α and 630 nm LED irradiation with the different energy density. The mRNA sequencing was performed to screen the differentially expressed genes (DEGs). In all datasets, 10 DEGs were identified through screening. The protein interaction network analysis showed that 8 out of the 10 DEGs interacted with each other including IL-6, CXCL2, CXCL3, MAF, PGF, IL-1RL1, RRAD and BMP4. This study focused on BMP4, which is identified as important morphogens in regulating the development and homeostasis. CCK-8 assay results showed that 630 nm LED irradiation did not affect the cell viability. The qPCR and ELISA results showed that TNF-α stimulation inhibited BMP4 mRNA and protein level and irradiation of 630 nm LED increased the BMP4 mRNA and protein level in MH7A cells. In CIA and transgenic hTNF-α mice models, H&E staining showed that irradiation of 630 nm LED decreased the histological scores assessed from inflammation and bone erosion, while BMP4 expression level was up-regulated after 630 nm LED irradiation. Pearson correlation analysis shown that BMP4 protein expression was negatively correlated with the histological score of CIA mice and transgenic hTNF-α mice. These results indicated that BMP4 increased by irradiation of 630 nm LED was associated with the amelioration of RA, which suggested that BMP4 may be a potential targeting gene for photobiomodulation.

BMP4 inhibits corneal neovascularization by interfering with tip cells in angiogenesis.

Corneal neovascularization (CNV) can lead to impaired corneal transparency, resulting in vision loss or blindness. The primary pathological mechanism underlying CNV is an imbalance between pro-angiogenic and anti-angiogenic factors, with inflammation playing a crucial role. Notably, a vascular endothelial growth factor（VEGF）-A gradient triggers the selection of single endothelial cells（ECs） into primary tip cells that guide sprouting, while a dynamic balance between tip and stalk cells maintains a specific ratio to promote CNV. Despite the central importance of tip-stalk cell selection and shuffling, the underlying mechanisms remain poorly understood. In this study, we examined the effects of bone morphogenetic protein 4 (BMP4) on VEGF-A-induced lumen formation in human umbilical vein endothelial cells (HUVECs) and CD34-stained tip cell formation. In vivo, BMP4 inhibited CNV caused by corneal sutures. This process was achieved by BMP4 decreasing the protein expression of VEGF-A and VEGFR2 in corneal tissue after corneal suture injury. By observing the ultrastructure of the cornea, BMP4 inhibited the sprouting of tip cells and brought forward the appearance of intussusception. Meanwhile, BMP4 attenuated the inflammatory response by inhibiting neutrophil extracellular traps （NETs）formation through the NADPH oxidase-2（NOX-2）pathway. Our results indicate that BMP4 inhibits the formation of tip cells by reducing the generation of NETs, disrupting the dynamic balance of tip and stalk cells and thereby inhibiting CNV, suggesting that BMP4 may be a potential therapeutic target for CNV.

Activation of BMP4-pSmad1/5 pathway impairs the function of VSMCs in intracranial aneurysms.

Intracranial aneurysms (IAs) are characterized by abnormal dilatation of the cerebral vessels. Vascular smooth muscle cells (VSMCs) are implicated in maintaining vascular homeostasis. Disordered VSMCs are one of the most common causes for occurrence and development of IAs. The bone morphogenetic protein 4 (BMP4) signalling pathway is involved in regulating cell proliferation, apoptosis, and differentiation. This study aimed to investigate the effects of BMP4 on VSMCs and its underlying mechanisms. BMP4 was upregulated in the VSMCs of IAs and caused apoptosis of VSMCs through Smad1/5 phosphorylation. In addition, BMP4 overexpression significantly promoted the proliferation and migration of VSMCs and induced a phenotypic transformation from contractile to inflammatory. Our findings facilitate further understanding of the occurrence and development of IAs and provide a potential therapeutic target.

Design and characterization of a novel tumor-homing cell-penetrating peptide for drug delivery in TGFBR3 high-expressing tumors.

Targeted therapy has attracted more and more attention in cancer treatment in recent years. However, due to the diversity of tumor types and the mutation of target sites on the tumor surface, some existing targets are no longer suitable for tumor therapy. In addition, the long-term administration of a single targeted drug can also lead to drug resistance and attenuate drug potency, so it is important to develop new targets for tumor therapy. The expression of Type III transforming growth factor ß receptor (TGFBR3) is upregulated in colon, breast, and prostate cancer cells, and plays an important role in the occurrence and development of these cancers, so TGFBR3 may be developed as a novel target for tumor therapy, but so far there is no report on this research. In this study, the structure of bone morphogenetic protein 4 (BMP4), one of the ligands of TGFBR3 was analyzed through the docking analysis with TGFBR3 and sequence charge characteristic analysis, and a functional tumor-targeting penetrating peptide T3BP was identified. The results of fluorescent labeling experiments showed that T3BP could target and efficiently enter tumor cells with high expression of TGFBR3, especially A549 cells. When the expression of TGFBR3 on the surface of tumor cells (HeLa) was knocked down by RNA interference, the high delivery efficiency of T3BP was correspondingly reduced by 40%, indicating that the delivery was TGFBR3-dependent. Trichosanthin (TCS, a plant-derived ribosome inactivating protein) fused with T3BP can enhance the inhibitory activity of the fusion protein on A549 cells by more than 200 times that of TCS alone. These results indicated that T3BP, as a novel targeting peptide that can efficiently bind TGFBR3 and be used for targeted therapy of tumors with high expression of TGFBR3. This study enriches the supply of tumor-targeting peptides and provides a new potential application option for the treatment of tumors with high expression of TGFBR3.

Ethnic Differences in the Brazilian Population Influence the Impact of BMP4 Genetic Variants on Susceptibility of Nonsyndromic Orofacial Clefts.

OBJECTIVE: The study evaluated the association of BMP4 tag-SNPs and SNP-SNP interactions involving genes active by BMP4 pathway during craniofacial development in the susceptibility of nonsyndromic orofacial clefts (NSOC) in the Brazilian population. DESIGN: Case-control study. SETTING: Brazilian Oral Cleft Group. PARTICIPANTS: The study included 881 healthy controls and 800 patients with different types of NSOC: 232 with cleft lip only (NSCLO), 568 with cleft lip and palate (NSCLP), and 274 with cleft palate only (NSCPO). INTERVENTIONS: The genomic DNA was genotyped with allelic discrimination assays for five BMP4 tag-SNPs (rs11623717, rs17563, rs2071047, rs2761887 and rs4898820), and analyzed their allelic and genotypic associations using multiple logistic regression. The interactions of these variants with genes involved in the BMP4 signaling pathway, including FGFR1, GREM1, NOG, VAX1 and the 4p16.2 locus, were explored. MAIN OUTCOME MEASURES: BMP4 variants in the NSOC risk. RESULTS: Although only nominal p values were identified when the whole sample was considered, subgroup analysis including the patients with high African genomic ancestry showed significant associations of rs2761887 with risk for nonsyndromic cleft lip with or without cleft palate (NSCL ± P)[(ORhom: 2.16; 95% CI: 1.21-3.85; p = 0.01) and (ORrec: 2.05; 95% CI: 1.21-3.47; p = 0.006)]. Thirteen significant SNP-SNP interactions involving BMP4 and the SNPs at FGFR1, GREM1, NOG and VAX1 and at locus 4p16.2 for increased risk of NSCL ± P were identified. CONCLUSIONS: Our results demonstrate an increased risk of NSCL ± P in Brazilian individuals with enrichment of African ancestry in the presence of the BMP4 rs2762887 polymorphism, and reveal relevant genetic contribution of SNP-SNP epistatic interactions involving BMP4 variants to NSCL ± P risk.

Trans differentiating human adipose-derived mesenchymal stem cells into male germ-like cells utilizing Rabbit Sertoli cells: An experimental study.

Background: Mesenchymal stem cells (MSCs) are deemed as potential new therapeutic agents for infertility treatment and adipose tissue (AT) becomes a potential MSCs source. To direct MSCs through the differentiation process properly, an environment comparable to the in vivo niche might be indispensable. Objective: This study aims to differentiate human AT-derived MScs (hAD-MScs) into male germ-like cells in vitro using a combination of rabbit Sertoli cells conditioned medium (SCCM), bone morphogenetic protein 4, and retinoic acid. Materials and Methods: MScs were isolated from human ATs of fertile and infertile donors. The verified MScs were differentiated using a 2-step protocol; the first step included 20 ng/ml bone morphogenetic protein 4 treatment. The second step was performed utilizing 1 µM retinoic acid and/or SCCM. The morphological changes and the expression of germ cell (GC)-specific markers: octamer-binding transcription factor-4; stimulated by retinoic-acid-8, synaptonemal complex protein-3, andprotamine-1 were assessed in the treated cells using quantitative polymerase chain reaction. Results: Induction of hAD-MScs resulted in the upregulation of GC-specific genes where SCCM treatment showed the highest expression. The synaptonemal complex protein-3andprotamine-1 gene expression was detected after 19 and 26 days of induction, respectively. PRM1 was detected in hAD-MScs cultured in SCCM earlier than in other treated groups. The treated cells became more elongated-like spindles and formed aggregates. Conclusion: hAD-MScs differentiated to GC lineage exhibited the ability to express GC-specific markers under in vitro conditions, and rabbit's Sertoli cells can be used for inducing transdifferentiation of hAD-MScs into germ-like cells.

The serum levels of activin A and bone morphogenetic protein-4 and -6 in patients with fibrodysplasia ossificans progressiva.

BACKGROUND: Fibrodysplasia ossificans progressiva (FOP) is an ultrarare and disabling genetic disorder of connective tissue characterized by congenital malformation of the great toes, and progressive heterotopic ossification (HO) in soft connective tissues. A gain-of-function mutation of activin A receptor type I (ACVR1) enables ACVR1 to recognize activin A as an agonist with bone morphogenetic protein (BMP) signalling that leads to HO. Previous studies confirmed that activin A stimulates BMP signalling in vitro and drives HO in mouse models of FOP. However, the roles for BMP4 and BMP6 in FOP are supported only by correlative evidence in vitro. Thus, it remains unclear whether the circulating levels of activin A, BMP4 and BMP6 correlate with flare-ups in FOP patients. Hence, we investigated the protein levels of activin A, BMP4 and BMP6 in the serum of FOP patients. RESULTS: We recruited 16 untreated FOP patients and 16 age- and sex- matched healthy control subjects in this study. The 16 FOP patients were retrospectively divided into the flare-up group (n = 8) and remission group (n = 8) depending on whether they had flare-ups or worsening of any joint movement in the last 6 months. The serum activin A, BMP4 and BMP6 levels were detected by enzyme-linked immunosorbent assay. The serum activin A, BMP4 and BMP6 levels were slightly higher in FOP patients (median: 434.05 pg/mL, 459.48 pg/mL and 67.84 pg/mL) versus healthy control subjects (median: 364.14 pg/mL, 450.39 pg/mL and 55.36 pg/mL). However, there were no statistically significant differences between the two groups (p > 0.05 for all items), nor were there significant differences between the flare-up and remission groups of FOP (p > 0.05 for all items). Univariate and multivariate logistic regression analyses showed that age, sex, and serum activin A, BMP4 and BMP6 levels were not related to flare-up in FOP patients. CONCLUSIONS: There were no significant differences in the serum levels of activin A, BMP4 and BMP6 in FOP patients compared with healthy control subjects. Serum activin A, BMP4 and BMP6 proteins might not be the stimulators for FOP flare-up, and may not be biomarkers for FOP diagnosis.

Role and Mechanism of BMP4 in Regenerative Medicine and Tissue Engineering.

Bone morphogenetic protein 4 (BMP4) is emerging as a promising cytokine for regenerative medicine and tissue engineering. BMP4 has been shown to promote the regeneration of teeth, periodontal tissue, bone, cartilage, the thymus, hair, neurons, nucleus pulposus, and adipose tissue, as well as the formation of skeletal myotubes and vessels. BMP4 can also contribute to the formation of tissues in the heart, lung, and kidney. However, there are certain deficiencies, including the insufficiency of the mechanism of BMP4 in some fields and an appropriate carrier of BMP4 for clinical use. There has also been a lack of in vivo experiments and orthotopic transplantation studies in some fields. BMP4 has great distance from the clinical application. Therefore, there are many BMP4-related studies waiting to be explored. This review mainly discusses the effects, mechanisms, and applications of BMP4 in regenerative medicine and tissue engineering over the last 10 years in various domains and possible improvements. BMP4 has shown great potential in regenerative medicine and tissue engineering. The research of BMP4 has broad development space and great value.

The Role of Bone Morphogenetic Protein 4 in Lung Diseases.

Bone morphogenetic protein 4 (BMP4) is a multifunctional secretory protein that belongs to the transforming growth factor ß superfamily. BMPs transduce their signaling to the cytoplasm by binding to membrane receptors of the serine/threonine kinase family, including BMP type I and type II receptors. BMP4 participates in various biological processes, such as embryonic development, epithelial-mesenchymal transition, and maintenance of tissue homeostasis. The interaction between BMP4 and the corresponding endogenous antagonists plays a key role in the precise regulation of BMP4 signaling. In this paper, we review the pathogenesis of BMP4-related lung diseases and the foundation on which BMP4 endogenous antagonists have been developed as potential targets.

Data mining and structural analysis for multi-tissue regeneration potential of BMP-4 and activator drugs.

Despite substantial progress in surgery, managing multi-tissue injuries is strenuous to accomplish and requires a multi-staged serial treatment of individual tissues. Stimulated regeneration affects the complete structural and functional repair of both hard and soft tissues post-injury and thus serves as an attractive therapeutic option to target multi-tissue injuries. This study utilized data mining and structural analysis to identify a target that has the ability to evoke healing of the two most commonly injured tissues i.e., bone and muscle, and stimulate the inherent vascular connectivity between the tissues. To find out the multipotential molecule the gene expression profile from GSE34747 was extracted and processed to identify the differentially expressed genes (DEGs). The DEGs were then subjected to gene ontology enrichment analysis to filter out a target that is likely to regulate the multi-tissue regeneration. Further, STITCH and PubChem databases were screened to determine a stimulatory drug against the identified target molecule. Finally, the binding affinity and stability of the potential drug candidate(s) against the target were analysed by molecular docking and molecular dynamics simulation. The results revealed that bone morphogenetic protein-4 (BMP-4) was associated with the regulation of the multiple regeneration processes. The computational screening results suggested Retinoic acid and Torularhodin as potential drug candidates for the stimulation of BMP-4. Both drugs demonstrated slightly different but stable interactions with BMP-4, suggesting that the identified drug candidates are likely to serve as potential leads to further enhance tissues regeneration.Communicated by Ramaswamy H. Sarma.

BMP4 Regulates EMT to be Involved in non-Syndromic Cleft lip With or Without Palate.

OBJECTIVE: In the previous study, we identified bone morphogenetic protein 4 (BMP4) responsible for non-syndromic cleft lip with or without cleft palate (NSCL/P). We aimed to elucidate the effects and mechanisms of BMP4 on epithelial-mesenchymal transition (EMT) through Smad1 signaling pathway to be involved in NSCL/P. METHODS: The human oral epidermoid carcinoma cells (KBs) were transfected with plasmids or small interfering RNA (siRNA) to build the models. The migration of the cells was evaluated by transwell assay. Western blotting and quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR) were used to detect the expressions of BMP4, E-cadherin, N-cadherin, EMT-related transcription factors snal1 and snal2, matrix metalloproteinase 2 (MMP2), MMP9, Smad1, and phosphorylated Smad1. RESULTS: In the overexpression group, the migration number of cells was increased significantly. The protein expression of E-cadherin was decreased significantly, while the protein expression level of the N-cadherin was increased significantly. The protein and mRNA expressions of MMP2, MMP9, snal1, and snal2 were significantly higher. The expression level of Smad1 was not significantly changed, while the phosphorylation of Smad1 was significantly increased. In the BMP4-siRNA group, the migrating number cells was significantly decreased. The protein expression of E-cadherin was increased significantly, while the expression of N-cadherin was significantly decreased. The protein and mRNA expressions of MMP2, MMP9, snal1, and snal2 were significantly lower than that of the control group. The expressions of Smad1 and phosphorylation of Smad1 were not significantly changed. CONCLUSIONS: BMP4 enhances cell migration and promotes cell EMT through Smad1 signaling pathway. Abnormal BMP4 mediates migration and EMT through other relevant signaling pathways resulting in NSCL/P. The study provides new insight into the mechanisms of NSCL/P associated with BMP4.n.

BMP4 is insufficient to differentiate umbilical cord mesenchymal stem cells into germ cell-like cells in vitro.

OBJECTIVES: Mesenchymal stem cell (MSC)-based therapies are expected to restore the fertility of infertile patients. In addition to MSC-derived paracrine effects to improve reproductive function, the differentiation of MSCs into germ cell (GC)-like cells is still a promising method to repair the injured reproductive system. The aim of this study was to examine the effect and potential mechanism of BMP4 in inducing umbilical cord MSC (UcMSC) transdifferentiation into GC-like cells. MATERIAL AND METHODS: UcMSCs were isolated, cultured and identified by flow cytometry and multilineage differentiation assays. After induction with 12.5 ng/mL BMP4 for 21 days, UcMSCs were collected for further examination. Immunofluorescence was used to detect the expression of Prdm1 and Prdm14; RT-PCR and RNA sequencing were used to detect differential gene expression (DEGs). RESULTS: The morphology of UcMSCs became large and flat after treatment with BMP4; the expression of GC-related genes (OCT4, Prdm1, Ifitm3 and Stella) was significantly downregulated, and further immunofluorescence results also confirmed the significant downregulation of Prdm1 in UcMSCs with BMP4 induction, while the expression of Prdm14 was significantly upregulated. The results of RNA sequencing and further analysis revealed no explicit correlation between BMP4 induction and the differentiation of UcMSCs into GC-like cells based on the 662 screened DEGs in UcMSCs with or without BMP4 induction. CONCLUSIONS: The differentiation of MSCs into GC-like cells is rather complex, and BMP4 alone is insufficient to induce UcMSCs to differentiate into GC-like cells, regardless of protein level or gene expression level.