Essential Role of BMP4 Signaling in the Avian Ceca in Colorectal Enteric Nervous System Development

The enteric nervous system (ENS) is principally derived from vagal neural crest cells that migrate caudally along the entire length of the gastrointestinal tract, giving rise to neurons and glial cells in two ganglionated plexuses. Incomplete migration of enteric neural crest-derived cells (ENCDC) leads to Hirschsprung disease, a congenital disorder characterized by the absence of enteric ganglia along variable lengths of the colorectum. Our previous work strongly supported the essential role of the avian ceca, present at the junction of the midgut and hindgut, in hindgut ENS development, since ablation of the cecal buds led to incomplete ENCDC colonization of the hindgut. In situ hybridization shows bone morphogenetic protein-4 (BMP4) is highly expressed in the cecal mesenchyme, leading us to hypothesize that cecal BMP4 is required for hindgut ENS development. To test this, we modulated BMP4 activity using embryonic intestinal organ culture techniques and retroviral infection. We show that overexpression or inhibition of BMP4 in the ceca disrupts hindgut ENS development, with GDNF playing an important regulatory role. Our results suggest that these two important signaling pathways are required for normal ENCDC migration and enteric ganglion formation in the developing hindgut ENS.

Bone Morphogenic Proteins and Their Antagonists in the Lower Airways of Stable COPD Patients

BACKGROUND

Bone morphogenic proteins (BMPs) and their antagonists are involved in the tissue development and homeostasis of various organs.

OBJECTIVE

To determine transcriptomic and protein expression of BMPs and their antagonists in stable COPD.

METHODS

We measured the expression and localization of BMPs and some relevant antagonists in bronchial biopsies of stable mild/moderate COPD (MCOPD) (n = 18), severe/very severe COPD (SCOPD) (n = 16), control smokers (CS) (n = 13), and control non-smokers (CNS) (n = 11), and in lung parenchyma of MCOPD (n = 9), CS (n = 11), and CNS (n = 9) using immunohistochemistry and transcriptome analysis, in vitro after the stimulation of the 16HBE cells.

RESULTS

In bronchial biopsies, BMP4 antagonists CRIM1 and chordin were increased in the bronchial epithelium and lamina propria of COPD patients. BMP4 expression was decreased in the bronchial epithelium of SCOPD and MCOPD compared to CNS. Lung transcriptomic data showed non-significant changes between groups. CRIM1 and chordin were significantly decreased in the alveolar macrophages and alveolar septa in COPD patients. External 16HBE treatment with BMP4 protein reduced the bronchial epithelial cell proliferation.

CONCLUSIONS

These data show an imbalance between BMP proteins and their antagonists in the lungs of stable COPD. This imbalance may play a role in the remodeling of the airways, altering the regenerative-reparative responses of the diseased bronchioles and lung parenchyma.

Bmp4 in Zebrafish Enhances Antiviral Innate Immunity through p38 MAPK (Mitogen-Activated Protein Kinases) Pathway

Bone morphogenetic proteins (BMPs) are a group of structurally and functionally related signaling molecules that comprise a subfamily, belonging to the TGF-β superfamily. Most BMPs play roles in the regulation of embryonic development, stem cell differentiation, tumor growth and some cardiovascular and cerebrovascular diseases. Although evidence is emerging for the antiviral immunity of a few BMPs, more BMPs are needed to determine whether this function is universal. Here, we identified the zebrafish bmp4 ortholog, whose expression is up-regulated through challenge with grass carp reovirus (GCRV) or its mimic poly(I:C). The overexpression of bmp4 in epithelioma papulosum cyprini (EPC) cells significantly decreased the viral titer of GCRV-infected cells. Moreover, compared to wild-type zebrafish, viral load and mortality were significantly increased in both larvae and adults of bmp4-/- mutant zebrafish infected with GCRV virus. We further demonstrated that Bmp4 promotes the phosphorylation of Tbk1 and Irf3 through the p38 MAPK pathway, thereby inducing the production of type I IFNs in response to virus infection. These data suggest that Bmp4 plays an important role in the host defense against virus infection. Our study expands the understanding of BMP protein functions and opens up new targets for the control of viral infection.

ADAM11 a novel regulator of Wnt and BMP4 signaling in neural crest and cancer

Introduction: Cranial neural crest (CNC) cells are induced at the border of the neural plate by a combination of FGF, Wnt, and BMP4 signaling. CNC then migrate ventrally and invade ventral structures where they contribute to craniofacial development. Methods: We used loss and gain of function experiments to determine phenotypes associated with the perturbation of Adam11 expression in Xenopus Laevis. Mass spectrometry to identify partners of Adam11 and changes in protein expression in CNC lacking Adam11. We used mouse B16 melanoma to test the function of Adam11 in cancer cells, and published database analysis to study the expression of ADAM11 in human tumors. Results: Here we show that a non-proteolytic ADAM, Adam11, originally identified as a putative tumor suppressor binds to proteins of the Wnt and BMP4 signaling pathway. Mechanistic studies concerning these non-proteolytic ADAM lack almost entirely. We show that Adam11 positively regulates BMP4 signaling while negatively regulating β-catenin activity. In vivo, we show that Adam11 influences the timing of neural tube closure and the proliferation and migration of CNC. Using both human tumor data and mouse B16 melanoma cells, we further show that ADAM11 levels similarly correlate with Wnt or BMP4 activation levels. Discussion: We propose that ADAM11 preserves naïve cells by maintaining low Sox3 and Snail/Slug levels through stimulation of BMP4 and repression of Wnt signaling, while loss of ADAM11 results in increased Wnt signaling, increased proliferation and early epithelium to mesenchyme transition.

Loss of TJP1 disrupts gastrulation patterning and increases differentiation toward the germ cell lineage in human pluripotent stem cells

Biological patterning events that occur early in development establish proper tissue morphogenesis. Identifying the mechanisms that guide these patterning events is necessary in order to understand the molecular drivers of development and disease and to build tissues in vitro. In this study, we use an in vitro model of gastrulation to study the role of tight junctions and apical/basolateral polarity in modulating bone morphogenic protein-4 (BMP4) signaling and gastrulation-associated patterning in colonies of human pluripotent stem cells (hPSCs). Disrupting tight junctions via knockdown (KD) of the scaffolding tight junction protein-1 (TJP1, also known as ZO1) allows BMP4 to robustly and ubiquitously activate pSMAD1/5 signaling over time, resulting in loss of the patterning phenotype and marked differentiation bias of pluripotent stem cells to primordial germ cell-like cells (PGCLCs). These findings give important insights into how signaling events are regulated and lead to spatial emergence of diverse cell types in vitro.

Investigation of the Role of BMP2 and -4 in ASD, VSD and Complex Congenital Heart Disease

Congenital heart malformations (CHMs) make up between 2 and 3% of annual human births. Bone morphogenetic proteins (BMPs) signalling is required for chamber myocardium development. We examined for possible molecular defects in the bone morphogenetic protein 2 and 4 (BMP2, -4) genes by sequencing analysis of all coding exons, as well as possible transcription or protein expression deregulation by real-time PCR and ELISA, respectively, in 52 heart biopsies with congenital malformations (atrial septal defect (ASD), ventricular septal defect (VSD), tetralogy ofFallot (ToF) and complex cases) compared to 10 non-congenital heart disease (CHD) hearts. No loss of function mutations was found; only synonymous single nucleotide polymorphisms (SNPs) in the BMP2 and BMP4 genes were found. Deregulation of the mRNA expression and co-expression profile of the two genes (BMP2/BMP4) was observed in the affected compared to the normal hearts. BMP2 and -4 protein expression levels were similar in normal and affected hearts. This is the first study assessing the role of BMP-2 and 4 in congenital heart malformations. Our analysis did not reveal molecular defects in the BMP2 and -4 genes that could support a causal relationship with the congenital defects present in our patients. Importantly, sustained mRNA and protein expression of BMP2 and -4 in CHD cases compared to controls indicates possible temporal epigenetic, microRNA or post-transcriptional regulation mechanisms governing the initial stages of cardiac malformation.

Local delivery of hrBMP4 as an anticancer therapy in patients with recurrent glioblastoma: a first-in-human phase 1 dose escalation trial

BACKGROUND

This Phase 1 study evaluates the intra- and peritumoral administration by convection enhanced delivery (CED) of human recombinant Bone Morphogenetic Protein 4 (hrBMP4) - an inhibitory regulator of cancer stem cells (CSCs) - in recurrent glioblastoma.

METHODS

In a 3 + 3 dose escalation design, over four to six days, fifteen recurrent glioblastoma patients received, by CED, one of five doses of hrBMP4 ranging from 0·5 to 18 mg. Patients were followed by periodic physical, neurological, blood testing, magnetic resonance imaging (MRI) and quality of life evaluations. The primary objective of this first-in-human study was to determine the safety, dose-limiting toxicities (DLT) and maximum tolerated dose (MTD) of hrBMP4. Secondary objectives were to assess potential efficacy and systemic exposure to hrBMP4 upon intracerebral infusion.

RESULTS

Intra- and peritumoral infusion of hrBMP4 was safe and well-tolerated. We observed no serious adverse events related to this drug. Neither MTD nor DLT were reached. Three patients had increased hrBMP4 serum levels at the end of infusion, which normalized within 4 weeks, without sign of toxicity. One patient showed partial response and two patients a complete (local) tumor response, which was maintained until the most recent follow-up, 57 and 30 months post-hrBMP4. Tumor growth was inhibited in areas permeated by hrBMP4.

CONCLUSION

Local delivery of hrBMP4 in and around recurring glioblastoma is safe and well-tolerated. Three patients responded to the treatment. A complete response and long-term survival occurred in two of them. This warrants further clinical studies on this novel treatment targeting glioblastoma CSCs.

TRIAL REGISTRATION

ClinicaTrials.gov identifier: NCT02869243.

BMP4 upregulates glycogen synthesis through the SMAD/SLC2A1 (GLUT1) signaling axis in hepatocellular carcinoma (HCC) cells

BACKGROUND

Excessive hepatic glycogen accumulation benefits tumorigenesis and cancer cell survival. We previously reported that BMP4 has the strongest ability to promote glycogenesis among the 14 BMPs in hepatocytes and augmented hepatocellular carcinoma (HCC) cell survival under hypoxia and hypoglycemia conditions by promoting the glycolysis pathway. However, the mechanism underlying BMP4's effect on glycogenesis in HCC remains elusive.

METHODS

The expression of BMP4 and SLC2A1 were acquired by analyzing the TCGA-LIHC dataset, as well as by immunohistochemical analysis of the 40 pairs of human HCC samples and para-tumor tissues. Gene expressions were detected by qPCR, immunoflurorescence staining, and Western blotting. Overexpression and silencing of BMP4 were accomplished through adenoviruses Ad-B4 and Ad-siB4 infection. Hepatic glycogen was detected by PAS staining. SLC2A1 (GLUT1) function was blocked by the inhibitor BAY-876. ChIP assay was used to determine the binding of SMADs to the promoter region of SLC2A1 in HCC cells. Lastly, the in vivo effect of BMP4-regulated SLC2A1 on HCC tumor growth was assessed in a xenograft model of HCC.

RESULTS

The elevated expression of BMP4 in HCC tumor tissues was highly correlated with hepatic glycogen accumulation in clinical samples. SLC2A1 was highly expressed in HCC tumor tissue and correlated with clinical stage and prognosis. Exogenous BMP4 augmented glycogen accumulation and upregulated the expression of glycogen synthesis-related genes in Huh7 and HepG2 cells, both of which were effectively blunted by SLC2A1inhibitor BAY-876. In mechanism, BMP4 activated SMAD5 to regulate the promoter of SLC2A1to enhance its expression. The in vivo xenograft experiments revealed that BMP4 promoted glycogen accumulation and tumor growth, which were effectively diminished by BAY-876.

CONCLUSION

These results demonstrate that BMP4 upregulates glycogen synthesis through the SMAD/SLC2A1 (GLUT1) signaling axis in HCC cells, which may be exploited as novel therapeutic targets for HCC treatment.

High glucose promotes the progression of colorectal cancer by activating the BMP4 signaling and inhibited by glucagon-like peptide-1 receptor agonist

BACKGROUND

The detailed molecular mechanism between type 2 diabetes mellitus (T2DM) and colorectal cancer (CRC) is still uncertain. Bone morphogenetic protein 4 (BMP4) dysregulation is implicated in T2DM and CRC, respectively. This study aims to investigate whether BMP4 can mediate the interaction of CRC with T2DM.

METHODS

We firstly explored the expression of BMP4 in The Cancer Genome Altas (TCGA) databases and CRC patients with or without DM from the Shanghai Tenth People's Hospital. The diabetic model of CRC cell lines in vitro and the mice model in vivo were developed to explore the BMP4 expression during CRC with or without diabetes. Further inhibition of BMP4 to observe its effects on CRC. Also, glucagon-like peptide-1 receptor agonist (GLP-1RA) was used to verify the underlying mechanism of hypoglycemic drugs on CRC via BMP4.

RESULTS

BMP4 expression was upregulated in CRC patients, and significantly higher in CRC patients with diabetes (P < 0.05). High glucose-induced insulin resistance (IR)-CRC cells and diabetic mice with metastasis model of CRC had increased BMP4 expression, activated BMP4-Smad1/5/8 pathway, and improved proliferative and metastatic ability mediated by epithelial-mesenchymal transition (EMT). And, treated CRC cells with exogenously BMP inhibitor-Noggin or transfected with lentivirus (sh-BMP4) could block the upregulated metastatic ability of CRC cells induced by IR. Meanwhile, GLP-1R was downregulated by high glucose-induced IR while unregulated by BMP4 inhibitor noggin, and treated GLP-1RA could suppress the proliferation of CRC cells induced by IR through downregulated BMP4.

CONCLUSIONS

BMP4 increased by high glucose promoted the EMT of CRC. The mechanism of the BMP4/Smad pathway was related to the susceptible metastasis of high glucose-induced IR-CRC. The commonly used hypoglycemic drug, GLP-1RA, inhibited the growth and promoted the apoptosis of CRC through the downregulation of BMP4. The result of our study suggested that BMP4 might serve as a therapeutic target in CRC patients with diabetes.

A Sequential Micro-Immunotherapy Medicine Increases Collagen Deposition in Human Gingival Fibroblasts and in an Engineered 3D Gingival Model under Inflammatory Conditions

Periodontal therapies use immune mediators, but their side effects can increase with dosage. Micro-immunotherapy (MI) is a promising alternative that employs immune regulators at low and ultralow doses to minimize adverse effects. In this study, the effects of 5 capsules and the entire 10-capsule sequence of the sequential MI medicine (MIM-seq) were tested in two in vitro models of periodontitis. Firstly, human gingival fibroblasts (hGFs) exposed to interleukin (IL)-1β to induce inflammation were treated with five different capsules of MIM-seq for 3 days or with MIM-seq for 24 days. Subsequently, MIM-seq was analyzed in a 3D model of human tissue equivalent of gingiva (GTE) under the same inflammatory stimulus. Simultaneously, a non-IL-1β-treated control and a vehicle were included. The effects of the treatments on cytotoxicity, collagen deposition, and the secreted levels of IL-1α, IL-6, prostaglandin E2 (PGE2), matrix metalloproteinase-1 (MMP-1), and tissue inhibitor of metalloproteinases-1 (TIMP-1) were evaluated. None of the tested items were cytotoxic. The complete sequence of MIM-seq decreased PGE2 release and restored collagen deposition levels induced by IL-1β treatment in hGFs exposed to IL-1β. MIM-seq treatment restored collagen production levels in both models. These promising preclinical findings suggest that MIM-seq should be further investigated for periodontitis treatment.

Are birds pseudoteeth and denticulations related to touch papilla? An investigation in parrot, goose, and chicken

We first studied the morphology and the development of goose denticulations, which develop mainly by a ripple process, and the touch papillae of the bill tip organ, which appears through an evagination process at the end of the beak. During their development, we observed the specific expression of PAX9, PITX2, and BMP4, while SHH was expressed mainly in the basal layer of the epithelium in a non-specific manner. Adult goose denticulations are associated with numerous columns. The goose denticulations and columns were filled with numerous Herbst and Grandry corpuscles, as well the touch papillae of the bill tip organ. Histological analysis of adult parrot pseudoteeth revealed that the osseous pseudoteeth were extended by similar columns filled with Herbst and Grandry corpuscles. We also examined adult and embryonic chicken beaks. During ontogeny, we observed a process of rostral evagination with folding associated with discrete ripples in the anterior part of the beak rudiment, in which PAX9, PITX2, and BMP4 are expressed. In the corresponding adult areas, there were numerous sensory corpuscles with rostral columns, which were similar to the features observed in goose. These observations support the hypothesis that pseudoteeth and denticulations constitute sensory organs, and that the touch papillae exhibit some similarities with pseudoteeth.

Lack of evidence that fibrillin1 regulates bone morphogenetic protein 4 activity in kidney or lung

BACKGROUND

The Bone morphogenetic protein 4 (BMP4) precursor protein is cleaved at two sites to generate an active ligand and inactive prodomain. The ligand and prodomain form a noncovalent complex following the first cleavage, but dissociate after the second cleavage. Transient formation of this complex is essential to generate a stable ligand. Fibrillins (FBNs) bind to the prodomains of BMPs, and can regulate the activity of some ligands. Whether FBNs regulate BMP4 activity is unknown.

RESULTS

Mice heterozygous for a null allele of Bmp4 showed incompletely penetrant kidney defects and females showed increased mortality between postnatal day 6 and 8. Removal of one copy of Fbn1 did not rescue or enhance kidney defects or lethality. The lungs of Fbn1+/- females had enlarged airspaces that were unchanged in Bmp4+/- ;Fbn1+/- mice. Additionally, removal of one or both alleles of Fbn1 had no effect on steady state levels of BMP4 ligand or on BMP activity in postnatal lungs.

CONCLUSIONS

These findings do not support the hypothesis that FBN1 plays a role in promoting BMP4 ligand stability or signaling, nor do they support the alternative hypothesis that FBN1 sequesters BMP4 in a latent form, as is the case for other BMP family members.

FTO promotes cervical cancer cell proliferation, colony formation, migration and invasion via the regulation of the BMP4/Hippo/YAP1/TAZ pathway

Cervical cancer is the fourth most common malignancy tumor worldwide with high incidence and mortality. Accumulating evidence indicated that through an m6A-dependent or m6A-independent mechanism, fat mass and obesity associated gene (FTO) exhibits the tumor-promoting and suppressive roles of FTO involved in various cancers, including cervical cancer. This study aims to verify the biological function and potential mechanisms of FTO in cervical cancer cell proliferation, colony formation, migration, and invasion in vitro as well as tumor growth in vivo. Herein, we confirmed that knockdown of FTO inhibits cell proliferation, colony formation, migration, and invasion of cervical cancer cells in vitro via cell counting kit-8 (CCK8) assay, colony formation assay, and transwell migration and invasion assay. The demethylase activity of FTO is required for cell proliferation, colony formation, migration, and invasion of cervical cancer cells in vitro. RNA sequencing, online database analysis, and western blotting revealed that FTO regulated the BMP4/Hippo/YAP1/TAZ pathway. In addition, FTO upregulates the expression of BMP4 in an m6A-dependent manner and binds to the N-terminal of BMP4 to form a dimer at the C-terminal in cervical cancer cells through protein-protein interaction. We further discovered that BMP4 treatment promoted cell proliferation, colony formation, migration, and invasion of cervical cancer cells, and rescue experiments validated that BMP4 treatment reversed the inhibition of FTO knockdown on the Hippo/YAP1/TAZ pathway and the progression of cervical cancer cells in vitro. Notably, the knockdown of FTO significantly suppressed xenograft tumor growth and the protein level of BMP4 in vivo. Collectively, our results demonstrate that the FTO promotes cervical cancer progression in vitro and in vivo via the regulation of the BMP4/Hippo/YAP1/TAZ pathway, suggesting that FTO acts as an oncogenic molecule and the FTO/BMP4 Hippo/YAP1/TAZ axis may serve as valuable targets for cervical cancer treatment.

Blood endothelial ALK1-BMP4 signaling axis regulates adult hair follicle stem cell activation

Blood vessels can play dual roles in tissue growth by transporting gases and nutrients and by regulating tissue stem cell activity via signaling. Correlative evidence implicates skin endothelial cells (ECs) as signaling niches of hair follicle stem cells (HFSCs), but functional demonstration from gene depletion of signaling molecules in ECs is missing to date. Here, we show that depletion of the vasculature-factor Alk1 increases BMP4 secretion from ECs, which delays HFSC activation. Furthermore, while previous evidence suggests a lymphatic vessel role in adult HFSC activation possibly through tissue drainage, a blood vessel role has not yet been addressed. Genetic perturbation of the ALK1-BMP4 axis in all ECs or the lymphatic ECs specifically unveils inhibition of HFSC activation by blood vessels. Our work suggests a broader relevance of blood vessels, adding adult HFSCs to the EC functional repertoire as signaling niches for the adult stem cells.

Bone Morphogenetic Protein-4 Impairs Retinal Endothelial Cell Barrier, a Potential Role in Diabetic Retinopathy

Bone Morphogenetic Protein 4 (BMP4) is a secreted growth factor of the Transforming Growth Factor beta (TGFβ) superfamily. The goal of this study was to test whether BMP4 contributes to the pathogenesis of diabetic retinopathy (DR). Immunofluorescence of BMP4 and the vascular marker isolectin-B4 was conducted on retinal sections of diabetic and non-diabetic human and experimental mice. We used Akita mice as a model for type-1 diabetes. Proteins were extracted from the retina of postmortem human eyes and 6-month diabetic Akita mice and age-matched control. BMP4 levels were measured by Western blot (WB). Human retinal endothelial cells (HRECs) were used as an in vitro model. HRECs were treated with BMP4 (50 ng/mL) for 48 h. The levels of phospho-smad 1/5/9 and phospho-p38 were measured by WB. BMP4-treated and control HRECs were also immunostained with anti-Zo-1. We also used electric cell-substrate impedance sensing (ECIS) to calculate the transcellular electrical resistance (TER) under BMP4 treatment in the presence and absence of noggin (200 ng/mL), LDN193189 (200 nM), LDN212854 (200 nM) or inhibitors of vascular endothelial growth factor receptor 2 (VEGFR2; SU5416, 10 μM), p38 (SB202190, 10 μM), ERK (U0126, 10 μM) and ER stress (Phenylbutyric acid or PBA, 30 μmol/L). The impact of BMP4 on matrix metalloproteinases (MMP2 and MMP9) was also evaluated using specific ELISA kits. Immunofluorescence of human and mouse eyes showed increased BMP4 immunoreactivity, mainly localized in the retinal vessels of diabetic humans and mice compared to the control. Western blots of retinal proteins showed a significant increase in BMP4 expression in diabetic humans and mice compared to the control groups (p < 0.05). HRECs treated with BMP4 showed a marked increase in phospho-smad 1/5/9 (p = 0.039) and phospho-p38 (p = 0.013). Immunofluorescence of Zo-1 showed that BMP4-treated cells exhibited significant barrier disruption. ECIS also showed a marked decrease in TER of HRECs by BMP4 treatment compared to vehicle-treated HRECs (p < 0.001). Noggin, LDN193189, LDN212854, and inhibitors of p38 and VEGFR2 significantly mitigated the effects of BMP4 on the TER of HRECs. Our finding provides important insights regarding the role of BMP4 as a potential player in retinal endothelial cell dysfunction in diabetic retinopathy and could be a novel target to preserve the blood-retinal barrier during diabetes.

BMP4-SMAD1/5/9-RUNX2 pathway activation inhibits neurogenesis and oligodendrogenesis in Alzheimer's patients' iPSCs in senescence-related conditions

In addition to increasing β-amyloid plaque deposition and tau tangle formation, inhibition of neurogenesis has recently been observed in Alzheimer's disease (AD). This study generated a cellular model that recapitulated neurogenesis defects observed in patients with AD, using induced pluripotent stem cell lines derived from sporadic and familial AD (AD iPSCs). AD iPSCs exhibited impaired neuron and oligodendrocyte generation when expression of several senescence markers was induced. Compound screening using these cellular models identified three drugs able to restore neurogenesis, and extensive morphological quantification revealed cell-line- and drug-type-dependent neuronal generation. We also found involvement of elevated Sma- and Mad-related protein 1/5/9 (SMAD1/5/9) phosphorylation and greater Runt-related transcription factor 2 (RUNX2) expression in neurogenesis defects in AD. Moreover, BMP4 was elevated in AD iPSC medium during neural differentiation and cerebrospinal fluid of patients with AD, suggesting a BMP4-SMAD1/5/9-RUNX2 signaling pathway contribution to neurogenesis defects in AD under senescence-related conditions.

Stratification and therapeutic potential of ELL in cytogenetic normal acute myeloid leukemia

Optimizing prognostic stratification of patients with cytogenetic normal acute myeloid leukemia (CN-AML), a highly heterogeneous subgroup in AML, appears to be important to improve its treatment and clinical outcome. Here, we report a potential role of ELL, a gene associated with leukemogenesis in AML, in prognostic stratification of CN-AML patients. By analyzing public available databases, we found that ELL was highly expressed in AML patients compared with healthy donors. Kaplan-Meier analysis revealed that ELL expression markedly correlated with short overall survival (OS) of CN-AML patients. In COX multivariable regression analysis, higher ELL expression was an independent prognostic factor for OS in CN-AML. Knockdown of ELL by shRNAs sensitized KG-1α cells to anti-leukemic agents such as idarubicin (IDA) and chidamide (CS055), supporting its role in therapeutic response and outcome in AML. To understand its function in CN-AML, we further analyzed the ELL-driving gene signature. ELL-related genes were particularly enriched in cell adhesion molecules, cell differentiation, pathways in cancer, sequence-specific DNA binding, and extracellular matrix (ECM)-receptor interaction. Analysis of the PPI network identified 25 hub genes, including the stem cell gene BMP4. While BMP4 expression was significantly associated with ELL in CN-AML, knockdown of ELL markedly down-regulated BMP4 expression, suggesting that ELL might function via regulating BMP4 in AML. Together, these observations suggest a novel mechanism underlying pro-leukemogenic role of ELL via BMP4 up-regulation in AML and its potential value to serve as a predictive biomarker for therapeutic response and outcome of CN-AML patients.

BMP4 aggravates mitochondrial dysfunction of HRMECs

Mitochondria are important places for the oxidative phosphorylation of glucose and the maintenance of cell oxidation and antioxidant stability. However, mitochondrial dysfunction causes cell dysfunction. Meanwhile, retinal vascular endothelial cell dysfunction may cause vascular inflammation, hemorrhage, angiogenesis, and other manifestations. Our previous studies have shown that Bone morphogenetic protein 4 (BMP4) is an important target for the treatment of retinal neovascularization, but the mechanism remains unclear. Therefore, our study aims to observe the effects of BMP4 on vascular endothelial cells and hopes to provide a new target for diabetic retinopathy. 4-Hydroxynonenal (4HNE), a kind of lipid peroxide, was used to induce the oxidative stress model. Human retinal microvascular endothelial cells (HRMECs) were randomly divided into control, 4HNE, negative control, and siBMP4 groups. Si-BMP4 significantly reduced leukocyte adhesion and 4HNE-induced high ROS level and restored the mitochondrial membrane potential and OCR. This indicates that BMP4 plays an important role in inducing leukocyte adhesion, oxidative stress, and mitochondrial dysfunction. The relationship between BMP4 and retinal vascular endothelial cell dysfunction is preliminarily confirmed by this study. Mitochondrial dysfunction and oxidative stress may be involved in BMP4-mediated retinal vascular endothelial cell dysfunction.

In vitro differentiation of primed human induced pluripotent stem cells into primordial germ cell-like cells

BACKGROUND

Previous studies have shown significant results in the differentiation of mouse-induced pluripotent stem cells (miPSCs) into primordial germ cell-like cells (PGCLCs) and that human iPSCs (hiPSCs) can also differentiate into PGCLCs; however, the efficiency of PGCLC induction from hiPSCs is < 5%. In this study, we examined a new protocol to differentiate hiPSCs into PGCLCs.

METHODS AND RESULTS

hiPSCs-derived embryoid bodies (EBs) were exposed to differentiate inducing factors, bone morphogenetic protein 4 (BMP4), and retinoic acid (RA) for 6 days. Cell differentiation was assessed by reverse transcriptase-polymerase chain reaction (RT-PCR) and immunofluorescence (IF) studies. Our results showed increased expression of the PRDM1 gene on the first day of differentiation. On other days, DAZL, VASA, and STRA8 genes increased, and the expression of PRDM1, NANOG, and OCT4 genes decreased. The expression of VASA, C-KIT, and STRA8 proteins was confirmed by IF. A flow cytometry analysis revealed that ~ 60% of differentiated cells were VASA- and STRA8-positive.

CONCLUSION

EB formation and constant exposure of EBs to BMP4 and RA lead to the differentiation of hiPSCs into PGCLCs.

Hypermethylation of the Bmp4 promoter dampens binding of HIF-1α and impairs its cardiac protective effects from oxidative stress in prenatally GC-exposed offspring

The exposure to an unhealthy environment in utero can lead to the occurrence of cardiovascular diseases in the offspring. Glucocorticoids (GC) are essential for normal development and maturation of fetal organs and is a first-line treatment for pregnant women affected by autoimmune diseases. However, excess prenatal GC exposure might program the development of fetal organs and cause a number of chronic diseases in later life. Our previous studies indicated that cardiac functions were significantly compromised in rat offspring prenatally exposed to the synthetic glucocorticoid dexamethasone (DEX), only after ischemia-reperfusion. In the present study, we further observed that DNA hypermethylation of bone morphogenetic protein 4 (Bmp4) promoter in cardiomyocytes caused by prenatal DEX exposure substantially dampened the binding activity of transcription factor HIF-1α induced by cardiac ischemia. Therefore, prenatal DEX exposure inhibits the induction of BMP4 upon I/R and attenuates the protective effects of BMP4 in cardiomyocytes, which eventually manifests as malfunction of the adult heart. Moreover, we employed two cardiac-specific Bmp4 knock-in mouse models and found that in vivo BMP4 overexpression could rescue the cardiac dysfunction caused by prenatal GC exposure. In depth mechanistic research revealed that BMP4 protects the cardiomyocytes from mitophagy and apoptosis by attenuating mitochondrial PGC-1α expression in a p-Smad and Parkin-dependent manner. These findings suggest that prenatal GC exposure increases the susceptibility of the offspring's heart to a "second strike" after birth, due to the failure of hypoxia-induced HIF-1α transactivation of the hypermethylated Bmp4 promoter in cardiomyocytes. Pretreatment with the DNA methylation inhibitor, 5-Aza-2'-deoxycytidine, could be a potential therapeutic method for this programming effect of GC exposure during pregnancy on neonatal cardiac dysfunction.

CXCL16 inhibits epithelial regeneration and promotes fibrosis during the progression of radiation enteritis

Radiation enteritis (RE) is a prevalent complication of radiotherapy for pelvic malignant tumors, characterized by severe intestinal epithelial destruction and progressive submucosal fibrosis. However, little is known about the pathogenesis of this disease, and so far, there is no specific targeted therapy. Here, we report that CXCL16 is upregulated in the injured intestinal tissues of RE patients and in a mouse model. Genetic deletion of Cxcl16 mitigates fibrosis and promotes intestinal stem cell-mediated epithelial regeneration after radiation injury in mice. Mechanistically, CXCL16 functions on myofibroblasts through its receptor CXCR6 and activates JAK3/STAT3 signaling to promote fibrosis and, at the same time, to transcriptionally modulate the levels of BMP4 and hepatocyte growth factor (HGF) in myofibroblasts. Moreover, we find that CXCL16 and CXCR6 auto- and cross-regulate themselves in positive feedback loops. Treatment with CXCL16 neutralizing monoclonal antibody attenuates fibrosis and improves the epithelial repair in RE mouse model. Our findings emphasize the important role of CXCL16 in the progression of RE and suggest that CXCL16 signaling could be a potential therapeutic target for RE. © 2022 The Pathological Society of Great Britain and Ireland.

Inhibition of BMP2 and BMP4 Represses Barrett's Esophagus While Enhancing the Regeneration of Squamous Epithelium in Preclinical Models

BACKGROUND & AIMS

Barrett's esophagus is considered to be a metaplastic lesion that predisposes for esophageal adenocarcinoma. Development of Barrett's esophagus is considered to be driven by sonic hedgehog mediated bone morphogenetic protein (BMP) signaling. We aimed to investigate in preclinical in vivo models whether targeting canonical BMP signaling could be an effective treatment for Barrett's esophagus.

METHODS AND RESULTS

Selective inhibition of BMP2 and BMP4 within an in vivo organoid model of Barrett's esophagus inhibited development of columnar Barrett's cells, while favoring expansion of squamous cells. Silencing of noggin, a natural antagonist of BMP2, BMP4, and BMP7, in a conditional knockout mouse model induced expansion of a Barrett's-like neo-columnar epithelium from multi-lineage glands. Conversely, in this model specific inhibition of BMP2 and BMP4 led to the development of a neo-squamous lineage. In an ablation model, inhibition of BMP2 and BMP4 resulted in the regeneration of neo-squamous epithelium after the cryoablation of columnar epithelium at the squamocolumnar junction. Through lineage tracing the generation of the neo-squamous mucosa was found to originate from K5+ progenitor squamous cells.

CONCLUSIONS

Here we demonstrate that specific inhibitors of BMP2 and BMP4 attenuate the development of Barrett's columnar epithelium, providing a novel potential strategy for the treatment of Barrett's esophagus and the prevention of esophageal adenocarcinoma.

Protein Kinase C Modulation Determines the Mesoderm/Extraembryonic Fate under BMP4 induction from Human Pluripotent Stem Cells

The interplay among mitogenic signaling pathways is crucial for proper embryogenesis. These pathways collaboratively act through intracellular master regulators to determine specific cell fates. Identifying the master regulators is critical to understanding embryogenesis and to developing new applications of pluripotent stem cells. In this report, we demonstrate protein kinase C (PKC) as an intrinsic master switch between embryonic and extraembryonic cell fates in the differentiation of human pluripotent stem cells (hPSCs). PKCs are essential to induce the extraembryonic lineage downstream of BMP4 and other mitogenic modulators. PKC-alpha (PKCα) suppresses BMP4-induced mesoderm differentiation, and PKC-delta (PKCδ) is required for trophoblast cell fate. PKC activation overrides mesoderm induction conditions and leads to extraembryonic fate. In contrast, PKC inhibition leads to β-catenin (CTNNB1) activation, switching cell fate from trophoblast to mesoderm lineages. This study establishes PKC as a signaling boundary directing the segregation of extraembryonic and embryonic lineages. The manipulation of intrinsic PKC activity could greatly enhance cell differentiation under mitogenic regulation in stem cell applications.

Possible roles of bone morphogenetic protein 4 in regulating endometrial function in cows

This study investigated the expression dynamics of bone morphogenetic protein 4 (BMP4) and its receptors (BMPR1A, BMPR1B, and BMPR2) in bovine endometrium and examined the physiological function and regulatory mechanism of BMP4 expression. The messenger RNA (mRNA) expression of BMP4 and its receptors was detected in bovine endometrium of both ipsilateral (corpus luteum [CL]-side) and contralateral (non-CL-side) uterine horns during the estrous cycle and early pregnancy. BMP4 protein levels were higher in the endometrial tissues obtained from those cows in early pregnancy than in the estrous cycle. Immunohistochemical analysis showed that BMP4 and its receptors were localized in endometrial epithelial cells. The addition of BMP4 to cultured endometrial epithelial cells did not affect caspase-3/-8 mRNA expression, whereas it significantly inhibited cell proliferation. Both prostaglandin (PG) E2 and PGF2α concentrations in the culture supernatant were decreased when stimulated by BMP4. Furthermore, BMP4 mRNA expression was increased by stimulation with tumor necrosis factor-α (TNF) and interferon-γ (IFNG). In conclusion, BMP4 is produced in bovine endometrial epithelial cells and may contribute to the regulation of cell proliferation and suppression of PG secretion through autocrine or paracrine mechanisms. BMP4 expression in the bovine endometrium may be regulated by TNF and IFNG.

Novel bone Morphogenetic Protein (BMP)-2/4 Consensus Peptide (BCP) for the Osteogenic Differentiation of C2C12 Cells

BACKGROUND

Despite the promising clinical potential of bone morphogenetic protein (BMP)-related therapies for bone formation, their side effects warrant the need for alternative therapeutic peptides. BMP family members can aid in bone repair; however, peptides derived from BMP2/ 4 have not yet been investigated.

METHODS

In this study, three candidates BMP2/4 consensus peptide (BCP) 1, 2, and 3 were identified and their ability to induce osteogenesis in C2C12 cells was analyzed. First, an alkaline phosphatase (ALP) staining assay was performed to evaluate the osteogenic effects of BCPs. Next, the effects of BCPs on RNA expression levels and protein abundances of osteogenic markers were explored. Furthermore, the transcriptional activity of ALP by BCP1 and in silico molecular docking model on BMP type IA receptor (BRIA) were performed.

RESULTS

BCP1-3 induced higher RUNX2 expression than BMP2. Interestingly, among them, BCP1 significantly promoted osteoblast differentiation more than BMP2 in ALP staining with no cytotoxicity. BCP1 significantly induced the osteoblast markers, and the highest RUNX2 expression was observed at 100 ng/mL compared to other concentrations. In transfection experiments, BCP1 stimulated osteoblast differentiation via RUNX2 activation and the Smad signaling pathway. Finally, in silico molecular docking suggested the possible binding sites of BCP1 on BRIA.

CONCLUSION

These results show that BCP1 promotes osteogenicity in C2C12 cells. This study suggests that BCP1 is the most promising candidate peptide to replace BMP2 for osteoblast differentiation.