Downregulated BMP-Smad1/5/8 signaling causes emphysema via dysfunction of alveolar type II epithelial cells.

Bone morphogenetic protein (BMP)-Smad1/5/8 signaling plays a crucial regulatory role in lung development and adult lung homeostasis. However, it remains elusive whether BMP-Smad1/5/8 signaling is involved in the pathogenesis of emphysema. In this study, we downregulated BMP-Smad1/5/8 signaling by overexpressing its antagonist Noggin in adult mouse alveolar type II epithelial cells (AT2s), resulting in an emphysematous phenotype mimicking the typical pathological features of human emphysema, including distal airspace enlargement, pulmonary inflammation, extracellular matrix remodeling, and impaired lung function. Dysregulation of BMP-Smad1/5/8 signaling in AT2s leads to inflammatory destruction dominated by macrophage infiltration, associated with reduced secretion of surfactant proteins and inhibition of AT2 proliferation and differentiation. Reactivation of BMP-Smad1/5/8 signaling by genetics or chemotherapy significantly attenuated the morphology and pathophysiology of emphysema and improved the lung function in Noggin-overexpressing lungs. We also found that BMP-Smad1/5/8 signaling was downregulated in cigarette smoke-induced emphysema, and that enhancing its activity in AT2s prevented or even reversed emphysema in the mouse model. Our data suggest that BMP-Smad1/5/8 signaling, located at the top of the signaling cascade that regulates lung homeostasis, represents a key molecular regulator of alveolar stem cell secretory and regenerative function, and could serve as a potential target for future prevention and treatment of pulmonary emphysema. © 2023 The Pathological Society of Great Britain and Ireland.

Structural analysis of the interaction between human cytokine BMP-2 and the antagonist Noggin reveals molecular details of cell chondrogenesis inhibition.

Bone morphogenetic proteins (BMPs) are secreted cytokines belonging to the transforming growth factor-ß superfamily. New therapeutic approaches based on BMP activity, particularly for cartilage and bone repair, have sparked considerable interest; however, a lack of understanding of their interaction pathways and the side effects associated with their use as biopharmaceuticals have dampened initial enthusiasm. Here, we used BMP-2 as a model system to gain further insight into both the relationship between structure and function in BMPs and the principles that govern affinity for their cognate antagonist Noggin. We produced BMP-2 and Noggin as inclusion bodies in Escherichia coli and developed simple and efficient protocols for preparing pure and homogeneous (in terms of size distribution) solutions of the native dimeric forms of the two proteins. The identity and integrity of the proteins were confirmed using mass spectrometry. Additionally, several in vitro cell-based assays, including enzymatic measurements, RT-qPCR, and matrix staining, demonstrated their biological activity during cell chondrogenic and hypertrophic differentiation. Furthermore, we characterized the simple 1:1 noncovalent interaction between the two ligands (KDca. 0.4 nM) using bio-layer interferometry and solved the crystal structure of the complex using X-ray diffraction methods. We identified the residues and binding forces involved in the interaction between the two proteins. Finally, results obtained with the BMP-2 N102D mutant suggest that Noggin is remarkably flexible and able to accommodate major structural changes at the BMP-2 level. Altogether, our findings provide insights into BMP-2 activity and reveal the molecular details of its interaction with Noggin.

DLL4/Notch blockade disrupts mandibular advancement-induced condylar osteogenesis by inhibiting H-type angiogenesis.

BACKGROUND: Blocking Delta-like 4 (DLL4)/Notch has emerged as a promising therapeutic target for the treatment of tumours by deregulating angiogenesis. However, DLL4/Notch serves as a negative regulator of angiogenesis in multiple organs while acting as a positive regulator of H-type angiogenesis in postnatal long bones. Therefore, the effect of DLL4/Notch signalling blockade on mandibular condylar osteogenesis attracted our attention. OBJECTIVE: To explore the effect of blocking DLL4/Notch on mandibular advancement (MA)-induced condylar osteogenesis. METHODS: Six-week-old young male C57BL/6J mice (n = 40) were randomly divided into four groups: control group, MA group, MA + Anti-DLL4 group and MA + IgG group. Of note, IgG served as the isotype control for the anti-DLL4. The femurs, tibias and mandibular condyles were collected after sacrificing mice on Day 31 for morphology, micro-computed tomography, immunofluorescence, histology and immunohistochemistry evaluation. RESULTS: First, DLL4/Notch blockade shortened femoral length and reduced bone mass by inhibiting H-type angiogenesis. Second, DLL4/Notch blockade disrupted MA-induced condylar head volume and quality by inhibiting H-type angiogenesis. Mechanistically, blocking DLL4/Notch reduced the number of runt-related transcription factor 2+ (RUNX2+ ) early osteoprogenitors and the expression of Noggin protein in the condylar subchondral bone by inhibiting H-type angiogenesis. In addition, blockade of DLL4/Notch also destroyed the condylar cartilage layer. CONCLUSION: DLL4/Notch blockade results in shortened femurs and osteopenia, as well as impaired MA-induced condylar osteogenic volume and quality in growing mice by inhibiting H-type angiogenesis. Therefore, when blocking DLL4/Notch is used as a treatment target for diseases, attention should be paid to its impact on the bone mass of mandibular condyle.

The Molecular Mechanism of Body Axis Induction in Lampreys May Differ from That in Amphibians.

Lamprey homologues of the classic embryonic inducer Noggin are similar in expression pattern and functional properties to Noggin homologues of jawed vertebrates. All noggin genes of vertebrates apparently originated from a single ancestral gene as a result of genome duplications. nogginA, nogginB and nogginC of lampreys, like noggin1 and noggin2 of gnathostomes, demonstrate the ability to induce complete secondary axes with forebrain and eye structures when overexpressed in Xenopus laevis embryos. According to current views, this finding indicates the ability of lamprey Noggin proteins to suppress the activity of the BMP, Nodal/Activin and Wnt/beta-catenin signaling pathways, as shown for Noggin proteins of gnathostomes. In this work, by analogy with experiments in Xenopus embryos, we attempted to induce secondary axes in the European river lamprey Lampetra fluviatilis by injecting noggin mRNAs into lamprey eggs in vivo. Surprisingly, unlike what occurs in amphibians, secondary axis induction in the lampreys either by noggin mRNAs or by chordin and cerberus mRNAs, the inductive properties of which have been described, was not observed. Only wnt8a mRNA demonstrated the ability to induce secondary axes in the lampreys. Such results may indicate that the mechanism of axial specification in lampreys, which represent jawless vertebrates, may differ in detail from that in the jawed clade.

A Spatio-Temporal-Dependent Requirement of Sonic Hedgehog in the Early Development of Sclerotome-Derived Vertebrae and Ribs.

Derived from axial structures, Sonic Hedgehog (Shh) is secreted into the paraxial mesoderm, where it plays crucial roles in sclerotome induction and myotome differentiation. Through conditional loss-of-function in quail embryos, we investigate the timing and impact of Shh activity during early formation of sclerotome-derived vertebrae and ribs, and of lateral mesoderm-derived sternum. To this end, Hedgehog interacting protein (Hhip) was electroporated at various times between days 2 and 5. While the vertebral body and rib primordium showed consistent size reduction, rib expansion into the somatopleura remained unaffected, and the sternal bud developed normally. Additionally, we compared these effects with those of locally inhibiting BMP activity. Transfection of Noggin in the lateral mesoderm hindered sternal bud formation. Unlike Hhip, BMP inhibition via Noggin or Smad6 induced myogenic differentiation of the lateral dermomyotome lip, while impeding the growth of the myotome/rib complex into the somatic mesoderm, thus affirming the role of the lateral dermomyotome epithelium in rib guidance. Overall, these findings underscore the continuous requirement for opposing gradients of Shh and BMP activity in the morphogenesis of proximal and distal flank skeletal structures, respectively. Future research should address the implications of these early interactions to the later morphogenesis and function of the musculo-skeletal system and of possible associated malformations.

Noggin contributes to brain metastatic colonization of lung cancer cells.

BACKGROUND: Brain metastasis is a common complication among patients with lung cancer, yet the underlying mechanisms remain unclear. In this study, we aimed to investigate the pathogenesis of brain metastasis in lung cancer. METHODS: We established highly colonizing metastatic lung cancer cells, A549-M2, through multiple implantations of A549 human lung cancer cells in the carotid artery of athymic nude mice. RESULTS: Compared to parental cells (M0), M2 cells demonstrated slower growth in culture plates and soft agar, as well as lower motility and higher adhesion, key characteristics of mesenchymal-epithelial transition (MET). Further analysis revealed that M2 cells exhibited decreased expression of epithelial-mesenchymal transition markers, including ZEB1 and Vimentin. M2 cells also demonstrated reduced invasiveness in co-culture systems. RNA sequencing and gene set enrichment analysis confirmed that M2 cells underwent MET. Intriguingly, depletion of Noggin, a BMP antagonist, was observed in M2 cells, and replenishment of Noggin restored suppressed migration and invasion of M2 cells. In addition, Noggin knockdown in control M0 cells promoted cell attachment and suppressed cell migration, suggesting that Noggin reduction during brain colonization causes inhibition of migration and invasion of metastatic lung cancer cells. CONCLUSIONS: Our results suggest that lung cancer cells undergo MET and lose their motility and invasiveness during brain metastatic colonization, which is dependent on Noggin.

HIF-1α drives the transcription of NOG to inhibit osteogenic differentiation of periodontal ligament stem cells in response to hypoxia.

Osteogenic differentiation of periodontal ligament stem cells (PDLSCs) is limited in hypoxia, and HIF-1α is key to the response to hypoxia. However, its mechanisms remain largely unknown. This study discovered an osteogenesis-related gene sensitive to hypoxia in PDLSCs, and investigated the molecular mechanisms between HIF-1α and the gene. NOG, a gene that negatively regulates osteogenesis, was discovered by RNA-seq. Under normoxic conditions, HIF-1α overexpression led to enhanced expression of NOG/Noggin and inhibited the expression of osteogenesis-related genes, while inhibition of HIF-1α reversed this effect. The expression of HIF-1α, NOG/Noggin and the osteogenesis-related genes were detected by qRT-PCR or Western blot. Mechanistically, we verified that HIF-1α binds to the hypoxia response element (-1505 to -1502) in the promotor of NOG to enhance secretion of Noggin by chromatin immunoprecipitation and a dual-luciferase reporter assay. IHC staining findings in an animal model verified that Noggin-associated osteogenic differentiation was inhibited in hypoxia. NOG displayed a concordant relationship with HIF-1α, and secreted more with increasing of HIF-1α. Hypoxia stabilized HIF-1α, which bound to the HRE (-1505 to -1502) of the NOG promotor to enhance NOG transcription resulted in inhibiting osteogenic differentiation of PDLSCs. This study offers a promising therapy for periodontitis.

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.

Identification of liver-derived bone morphogenetic protein (BMP)-9 as a potential new candidate for treatment of colorectal cancer.

Colorectal cancer (CRC) is a high-incidence malignancy worldwide which still needs better therapy options. Therefore, the aim of the present study was to investigate the responses of normal or malignant human intestinal epithelium to bone morphogenetic protein (BMP)-9 and to find out whether the application of BMP-9 to patients with CRC or the enhancement of its synthesis in the liver could be useful strategies for new therapy approaches. In silico analyses of CRC patient cohorts (TCGA database) revealed that high expression of the BMP-target gene ID1, especially in combination with low expression of the BMP-inhibitor noggin, is significantly associated with better patient survival. Organoid lines were generated from human biopsies of colon cancer (T-Orgs) and corresponding non-malignant areas (N-Orgs) of three patients. The N-Orgs represented tumours belonging to three different consensus molecular subtypes (CMS) of CRC. Overall, BMP-9 stimulation of organoids promoted an enrichment of tumour-suppressive gene expression signatures, whereas the stimulation with noggin had the opposite effects. Furthermore, treatment of organoids with BMP-9 induced ID1 expression (independently of high noggin levels), while treatment with noggin reduced ID1. In summary, our data identify the ratio between ID1 and noggin as a new prognostic value for CRC patient outcome. We further show that by inducing ID1, BMP-9 enhances this ratio, even in the presence of noggin. Thus, BMP-9 is identified as a novel target for the development of improved anti-cancer therapies of patients with CRC.

A simple method to generate human airway epithelial organoids with externally orientated apical membranes.

Organoids, which are self-organizing three-dimensional cultures, provide models that replicate specific cellular components of native tissues or facets of organ complexity. We describe a simple method to generate organoid cultures using isolated human tracheobronchial epithelial cells grown in mixed matrix components and supplemented at day 14 with the Wnt pathway agonist R-spondin 2 (RSPO2) and the bone morphogenic protein antagonist Noggin. In contrast to previous reports, our method produces differentiated tracheobronchospheres with externally orientated apical membranes without pretreatments, providing an epithelial model to study cilia formation and function, disease pathogenesis, and interaction of pathogens with the respiratory mucosa. Starting from 3 × 105 cells, organoid yield at day 28 was 1,720 ± 302. Immunocytochemistry confirmed the cellular localization of airway epithelial markers, including CFTR, Na+/K+ ATPase, acetylated-α-tubulin, E-cadherin, and ZO-1. Compared to native tissues, expression of genes related to bronchial differentiation and ion transport were similar in organoid and air-liquid interface (ALI) cultures. In matched primary cultures, mean organoid cilia length was 6.1 ± 0.2 µm, similar to that of 5.7 ± 0.1 µm in ALI cultures, and ciliary beating was vigorous and coordinated with frequencies of 7.7 ± 0.3 Hz in organoid cultures and 5.3 ± 0.8 Hz in ALI cultures. Functional measurement of osmotically induced volume changes in organoids showed low water permeability. The generation of numerous single testable units from minimal starting material complements prior techniques. This culture system may be useful for studying airway biology and pathophysiology, aiding diagnosis of ciliopathies, and potentially for high-throughput drug screening.

EGF and BMPs Govern Differentiation and Patterning in Human Gastric Glands.

BACKGROUND & AIMS: The homeostasis of the gastrointestinal epithelium relies on cell regeneration and differentiation into distinct lineages organized inside glands and crypts. Regeneration depends on Wnt/ß-catenin pathway activation, but to understand homeostasis and its dysregulation in disease, we need to identify the signaling microenvironment governing cell differentiation. By using gastric glands as a model, we have identified the signals inducing differentiation of surface mucus-, zymogen-, and gastric acid-producing cells. METHODS: We generated mucosoid cultures from the human stomach and exposed them to different growth factors to obtain cells with features of differentiated foveolar, chief, and parietal cells. We localized the source of the growth factors in the tissue of origin. RESULTS: We show that epidermal growth factor is the major fate determinant distinguishing the surface and inner part of human gastric glands. In combination with bone morphogenetic factor/Noggin signals, epidermal growth factor controls the differentiation of foveolar cells vs parietal or chief cells. We also show that epidermal growth factor is likely to underlie alteration of the gastric mucosa in the precancerous condition atrophic gastritis. CONCLUSIONS: Use of our recently established mucosoid cultures in combination with analysis of the tissue of origin provided a robust strategy to understand differentiation and patterning of human tissue and allowed us to draw a new, detailed map of the signaling microenvironment in the human gastric glands.

Inhibition of the BMP pathway prevents development of Barrett's-associated adenocarcinoma in a surgical rat model.

INTRODUCTION: Esophageal adenocarcinoma (EAC) is an aggressive cancer, associated with reflux esophagitis and intestinal metaplasia (IM). One underlying biological mechanism, which possibly drives the development of EAC, is the dysregulated expression of Bone Morphogenetic Proteins (BMPs). AIM: To investigate if local delivery of Noggin, a BMP antagonist, reduced EAC. METHODS: After obtaining proof of principal on local delivery of a Noggin/Sucralfate substance, a randomized controlled trial to test the effects of Noggin on EAC development was performed in a surgical rat model. In the model, an esophago-jejunostomy leads to development of reflux-esophagitis, IM and eventually EAC. Rats were treated by Noggin/Sucralfate or Sucralfate alone. Treatment was administered from 26 to 29 weeks after the operation. RESULTS: Of the 112 operated rats, 52 survived beyond 26 weeks. Finally, 25 rats treated with Noggin/Sucralfate and 21 with Sucralfate, were evaluated. At the end, 39 (85%) of the animals had IM while 28 (61%) developed cancer. There were significantly more cancers in the Noggin/Sucralfate arm (50%) versus the Sucralfate group (73%) (Chi square, P < 0.05). Most cancers were mucous producing T3 adenocarcinomas. There were no significant differences in the amount of IM, size or grade of the cancers, or expression of columnar and squamous markers between the two groups. CONCLUSION: In this study, we demonstrated that inhibition of BMPs by Noggin reduced development of EAC in a surgical esophagitis-IM-EAC rat model. In future, effective targeting of the BMP pathway with selective BMP-inhibitors could become an important asset to improve EAC patient outcome.

Noggin, an inhibitor of bone morphogenetic protein signaling, antagonizes TGF-ß1 in a mouse model of osteoarthritis.

Osteoarthritis (OA) is the most common joint disease worldwide; however, disease-modifying treatments are lacking because of the complicated pathological mechanisms. As a breakthrough, aberrant activation of transforming growth factor-ß 1 (TGF-ß1)in subchondral bone has been confirmed as an essential pathomechanism for OA progression, and has become a potential therapeutic target. In addition to R&D on neutralizing antibodies, small-molecule antagonists and chemical medicines, native antagonists of TGF-ß1 could be exploited as another promising approach. Noggin (NOG) is an antagonist of bone morphogenetic proteins (BMPs) and was reported to effectively attenuate OA by protecting cartilage and preventing pathological subchondral bone remodeling. However, the underlying mechanisms have not been fully clarified. We first detected the distribution of NOG in knee joints of an OA mouse model, which showed upregulation at early stage of OA but downregulation later in the subchondral bone and no significant change in the articular cartilage. Furthermore, the interaction between NOG and TGF-ß1 was verified, which in turn suppressed the downstream SMAD2/3 activity of TGF-ß1. Moreover, the proliferation and chondrogenesis of mesenchymal stem cells (MSCs) were not significantly influenced by NOG. Taken together, the results showed that NOG antagonized TGF-ß1 but did not repress MSC proliferation and chondrogenesis; thus, it seems promising for OA treatment.

Niche-mediated BMP/SMAD signaling regulates lung alveolar stem cell proliferation and differentiation.

The bone morphogenetic protein (BMP) signaling pathway, including antagonists, functions in lung development and regeneration of tracheal epithelium from basal stem cells. Here, we explore its role in the alveolar region, where type 2 epithelial cells (AT2s) and Pdgfrα+ type 2-associated stromal cells (TASCs) are components of the stem cell niche. We use organoids and in vivo alveolar regrowth after pneumonectomy (PNX) - a process that requires proliferation of AT2s and differentiation into type 1 cells (AT1s). BMP signaling is active in AT2s and TASCs, transiently declines post-PNX in association with upregulation of antagonists, and is restored during differentiation of AT2s to AT1s. In organoids, BMP4 inhibits AT2 proliferation, whereas antagonists (follistatin, noggin) promote AT2 self-renewal at the expense of differentiation. Gain- and loss-of-function genetic manipulation reveals that reduced BMP signaling in AT2s after PNX allows self-renewal but reduces differentiation; conversely, increased BMP signaling promotes AT1 formation. Constitutive BMP signaling in Pdgfrα+ cells reduces their AT2 support function, both after PNX and in organoid culture. Our data reveal multiple cell-type-specific roles for BMP signaling during alveolar regeneration.

Prognostic value of noggin protein expression in patients with resected gastric cancer.

BACKGROUND: Noggin and RNA-binding protein for multiple splicing 2 (RBPMS2) are known to regulate the expression of smooth muscle cells, endothelial cells, and osteoblasts. However, the prognostic role of combined Noggin and RBPMS2 expression in resected gastric cancer (GC) is unclear. METHODS: A total of 163 patients with GC who underwent gastrectomy were included in this study. The expression of Noggin and RBPMS2 proteins in tumor cells at the tumor center and invasive front of resected GC was evaluated by immunohistochemistry, and in conjunction with clinicopathological parameters the patient survival was analyzed. RESULTS: RBPMS2 protein expression was high at the tumor center (n = 86, 52.8%) and low at the invasive front (n = 69, 42.3%), while Noggin protein expression was high in both tumor center (n = 91, 55.8%) and the invasive front (n = 90, 55.2%). Noggin expression at the invasive front and tumor center was significantly decreased in advanced T stage, non-intestinal-type (invasive front, P = 0.008 and P <  0.001; tumor center lesion, P = 0.013 and P = 0.001). RBPMS2 expression at the invasive front was significantly decreased in non-intestinal-type and positive lymphatic invasion (P <  0.001 and P = 0.013). Multivariate analysis revealed that high Noggin protein expression of the invasive front was an independent prognostic factor for overall survival (hazard ratio [HR], 0.58; 95% confidence interval [CI]; 0.35-0.97, P <  0.036), but not at the tumor center (HR, 1.35; 95% CI; 0.81-2.26, P = 0.251). CONCLUSIONS: Our study indicates that high Noggin expression is a crucial prognostic factor for favorable outcomes in patients with resected GC.

Gender-Related Differences in BMP Expression and Adult Hippocampal Neurogenesis within Joint-Hippocampal Axis in a Rat Model of Rheumatoid Arthritis.

BMPs regulate synovial quiescence and adult neurogenesis in the hippocampus in non-stress conditions. However, changes in BMP expression that are induced by inflammation during rheumatoid arthritis (RA) have not yet been reported. Here, we show that signalling with synovial BMPs (BMP-4 and -7) mediates the effect of systemic inflammation on adult neurogenesis in the hippocampus during pristane-induced arthritis (PIA) in Dark Agouti (DA) rats, an animal model of RA. Moreover, we show gender differences in BMP expressions and their antagonists (Noggin and Gremlin) during PIA and their correlations with the clinical course and IL-17A and TNF-α levels in serum. Our results indicate gender differences in the clinical course, where male rats showed earlier onset and earlier recovery but a worse clinical course in the first two phases of the disease (onset and peak), which correlates with the initial increase of serum IL-17A level. The clinical course of the female rats worsened in remission. Their prolonged symptoms could be a reflection of an increased TNF-α level in serum during remission. Synovial inflammation was greater in females in PIA-remission with greater synovial BMP and antagonist expressions. More significant correlations between serum cytokines (IL-17A and TNF-α), and synovial BMPs and their antagonists were found in females than in males. On the other hand, males showed an increase in hippocampal BMP-4 expression during the acute phase, but both genders showed a decrease in antagonist expressions during PIA in general. Both genders showed a decrease in the number of Ki-67+ and SOX-2+ and DCX+ cells and in the ratio of DCX+ to Ki67+ cells in the dentate gyrus during PIA. However, in PIA remission, females showed a faster increase in the number of Ki67+, SOX-2+, and DCX+ cells and a faster increase in the DCX/Ki67 ratio than males. Both genders showed an increase of hippocampal BMP-7 expression during remission, although males constantly showed greater BMP-7 expression at all time points. Our data show that gender differences exist in the BMP expressions in the periphery-hippocampus axis and in the IL-17A and TNF-α levels in serum, which could imply differences in the mechanisms for the onset and progression of the disease, the clinical course severity, and adult neurogenesis with subsequent neurological complications between genders.

Differential expression of BMP inhibitors gremlin and noggin in Hydra suggests distinct roles during budding and patterning of tentacles.

BACKGROUND: Mechanisms regulating BMP and Wnt pathways and their interactions are not well studied in Hydra. RESULTS: We report identification of BMP inhibitor gremlin, comparison of its expression with that of noggin and possible antagonism between Wnt and BMP signaling in Hydra. Gremlin is expressed in body column with high levels in budding region and in early buds. Noggin, on the other hand, is expressed in the hypostome, base of tentacles, lower body column, and basal disc. During budding, noggin is expressed at the sites of tentacle emergence. This was confirmed in ectopic tentacles in polyps treated with alsterpaullone (ALP), a GSK-3ß inhibitor that leads to upregulation of Wnt pathway. RT-PCR data show that upregulation of Wnt is accompanied by downregulation of bmp 5-8b though noggin and gremlin remain unaltered till 24 hours. CONCLUSIONS: Different expression patterns of gremlin and noggin suggest their roles in budding and patterning of tentacles, respectively. Further, bmp 5-8b inhibition by activated Wnt signaling does not directly involve noggin and gremlin in Hydra. Our data suggest that Wnt/BMP antagonism may have evolved early for defining the oral-aboral axis, while the involvement of BMP antagonists during axial patterning is a recent evolutionary acquisition within the Bilateria lineage.

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OBJECTIVES: To explore the effect of intrathecal administration of exogenous noggin (NOG) on the pain behavior in the neuropathic pain (NP) rats through L5 spinal nerve ligation (SNL), and to examine the regulative role of NOG in astrocyte activation, inflammatory cytokines and downstream signals. METHODS: A total of 40 adult male Sprague Dawley (SD) rats were randomly divided into 3 groups: a control group (n=10), a SNL group (SNL+intrathecal injection of artificial cerebrospinal fluid, n=15), and a SNL+NOG group (SNL+intrathecal injection of recombinant NOG protein, n=15). Von-Frey filaments were used to test the changes of paw withdrawal threshold (PWT) at Day 1 before operation, and Day 1, Day 4, Day 7 and Day 14 after operation in each group. Immunofluorescence was used to observe the activation of astrocyte located in the dorsal horn of spinal cord in the 3 groups. Western blotting was conducted to detect the expression levels of glial fibrillary acidic protein (GFAP), interleukin-6 (IL-6), signal transducer and activator of transcription (STAT3) and phosphorylation STAT3 (p-STAT3). RESULTS: Compared with the control group, the PWT in the SNL group was markedly decreased at each time point, together with the increase in GFAP, IL-6 and the ratio of p-STAT3/STAT3 (all P<0.05). Meanwhile, compared with the SNL group, the PWT in the lumbar swelling of spinal cord in the SNL+NOG group was elevated at Day 4 and lasted to Day 14 (P<0.05), accompanied by the decrease in GFAP, IL-6 and the ratio of p-STAT3/STAT3 (all P<0.05). CONCLUSIONS: The intrathecal administration of NOG may alleviate NP in the SNL rats through inhibiting astrocyte activation and down-regulating the STAT3 signal pathway.

Structural basis of BMP-2 and BMP-7 interactions with antagonists Gremlin-1 and Noggin in Glioblastoma tumors.

In Glioblastoma (GBM) brain tumors, both Gremlin-1 and Noggin are reported to bind to BMP and inhibit BMP-signaling, thereby allowing the cell to maintain tumorous morphology. Enlisting the interfacial residues important for protein-protein complex formation between BMPs (BMP-2 and BMP-7) and antagonists (Gremlin-1 and Noggin), we analyzed the structural basis of their interactions. We found possible key mutations that destabilize these complexes, which may prevent GBM development. It was also observed that when the interfacial residues were either mutated to histidine or tryptophan, it led to higher destabilization energy values. Besides, our study of the Noggin interactive model of BMP-2 suggested preferential binding at binding site II over binding site I. In the case of Gremlin-1 and BMPs, our research, along with few previous studies, indicates a close-ended cis-trans interactive model.

Synergistic effects of Rho kinase inhibitor Y-27632 and Noggin overexpression on the proliferation and neuron-like cell differentiation of stem cells derived from human exfoliated deciduous teeth.

Stem cells from human exfoliated deciduous teeth (SHEDs) are highly proliferative, clonogenic, and multipotent stem cells with a neural crest cell origin. This property could be a desirable option for potential therapeutic applications. In this study, we focus on the effects of Rho kinase inhibitors Y-27632 and Noggin on the proliferation of SHEDs and their differentiation into neuron-like cells. SHEDs were extracted from 10 samples of deciduous teeth obtained from healthy children aged from 5 to 10. The passaged SHEDs were transfected with Noggin, Y-27632, or their combination. By means of MTT and colony formation assays, the effects of Y-27632 and Noggin on cell viability and colony formation were detected. Cellular morphology and neurosphere formation were observed under a microscope. Y-27632 transfection in SHEDs showed enhanced cell viability, colony formation, and neurosphere formation indicating that Y-27632 could promote cell proliferation of SHEDs. Furthermore, we observed that the SHEDs treated with Noggin in combination with Y-27632 displayed typical neuron-like cell morphology and reticular processes. Noggin or Y-27632 alone or in combination induced obviously increased NSE, Nestin, and GFAP levels, which were highest in SHEDs treated with the combination of Noggin and Y-27632. These findings suggest that Y-27632 promotes the proliferation of SHEDs, and Y-27632 and Noggin in combination have a synergistic effect on promoting differentiation of SHEDs into neuron-like cells.