Secreted phosphoprotein 24 kD (Spp24) and Spp14 affect TGF-β induced bone formation differently

SPP2 plays a role in the tumorigenesis of hepatocellular carcinoma: A bioinformatic based analysis

OBJECTIVES

Hepatocellular carcinoma (HCC) patients at the same stage exhibit different prognosis, and the underlying molecular mechanism remains unclear. This study aims to identify the key genes impacting the prognosis of HCC patients.

METHODS

Differentially expressed gene analyses were performed between HCC samples and normal ones, and between patients with long overall survival (OS) and those with short OS, in TCGA-LIHC and GSE14520 datasets. The Kaplan-Meier method with log-rank test was used to evaluate the role of secreted phosphoprotein 2 (SPP2) in the prognosis of HCC patients. Gene set enrichment analysis (GSEA) was used to understand the difference of enriched signaling pathways between SPP2-stratified HCC subgroups. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed to predict the potential functional pathways in which SPP2 might participate.

RESULTS

SPP2 was significantly down-regulated in tumors when compared with normal tissues, or in tumor samples with short OS when compared with those with long OS [fold change (FC)>2 and false discovery rate (FDR)<0.05]. Low expression of SPP2 was associated with worse clinicopathological features like vascular invasion (P=1.6e-05), poor cancer status (with tumor, P=0.021), advanced T stage (T3 or T4, P=4.5e-04), advanced TNM stage (stage III or IV, P=3.1e-04), and with unfavorable prognosis (shorter OS, P=0.002). Gene enrichment analyses revealed that SPP2 might involve in the metabolic homeostasis of HCC and in the development of liver fibrosis and cirrhosis.

CONCLUSIONS

SPP2 might inhibit the development of liver fibrosis and cirrhosis and the tumorigenesis of HCC, and analogs of SPP2 might be potential drugs in the prevention of these diseases.

SWATH-MS analysis of plasma proteins among Indian HIV-1 infected patients

The identification and characterization of plasma proteins in drug resistant and drug sensitive in HIV-1 infected/AIDS patients were carried out using the SWATH-MS protocol. In total, 204 proteins were identified and quantified, 57 proteins were differentially expressed, out of which 25 proteins were down regulated and 32 proteins were up regulated in drug resistant patients. Six proteins such as complement C4-A, immunoglobulin heavy variable 1-2, carboxylic ester hydrolase, fibulin-1, immunoglobulin lambda constant7, secreted phosphoprotein 24 were differentially expressed in individuals with drug resistant HIV as compared to individuals with drug sensitive HIV. Gene ontology of 57 differentially expressed proteins was analysed and documented.

Secreted phosphoprotein 24 kD (Spp24) inhibits the growth of human osteosarcoma through the BMP-2/Smad signaling pathway

Autocrine stimulation of tumor cells is an important mechanism for the growth of skeletal tumors. In tumors that are sensitive, growth factor inhibitors can dramatically reduce tumor growth. In this study, our aim was to investigate the effects of Secreted phosphoprotein 24 kD (Spp24) on the growth of osteosarcoma (OS) cells in the presence and absence of exogenous BMP-2 both in vitro and in vivo. Our study demonstrated that Spp24 inhibited proliferation and promoted apoptosis of OS cells as confirmed by 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide assay and immunohistochemical staining. We found that BMP-2 increased the mobility and invasiveness of tumor cells in vitro whereas Spp24 inhibited both of these processes alone and in the presence of exogenous BMP-2. Phosphorylation of Smad1/5/8 and Smad8 gene expression was enhanced by treatment with BMP-2 but inhibited by treatment with Spp24. Subcutaneous and intratibial tumor models in nude mice demonstrated that BMP-2 promoted OS growth in vivo, while Spp24 significantly inhibited tumor growth. We conclude that the BMP-2/Smad signaling pathway is involved in the pathogenesis of OS growth and that Spp24 inhibits the growth of human OS induced by BMP-2 both in vitro and in vivo. Interruption of Smad signaling and increased apoptosis appear to be the primary mechanisms involved. These results confirm the potential of Spp24 as a therapeutic agent for the treatment of OS and other skeletal tumors.

Finding New Ways How to Control BACE1

Recently, all applications of BACE1 inhibitors failed as therapeutical targets for Alzheimer´s disease (AD) due to severe side effects. Therefore, alternative ways for treatment development are a hot research topic. The present analysis investigates BACE1 protein-protein interaction networks and attempts to solve the absence of complete knowledge about pathways involving BACE1. A bioinformatics analysis matched the functions of the non-substrate interaction network with Voltage-gated potassium channels, which also appear as top priority protein nodes. Targeting BACE1 interactions with PS1 and GGA-s, blocking of BACE1 access to APP by BRI3 and RTN-s, activation of Wnt signaling and upregulation of β-catenin, and brain delivery of the extracellular domain of p75^NTR, are the main alternatives to the use of BACE 1 inhibitors highlighted by the analysis. The pathway enrichment analysis also emphasized substrates and substrate candidates with essential biological functions, which cleavage must remain controlled. They include ephrin receptors, ROBO1, ROBO2, CNTN-s, CASPR-s, CD147, CypB, TTR, APLP1/APLP2, NRXN-s, and PTPR-s. The analysis of the interaction subnetwork of BACE1 functionally related to inflammation identified a connection to three cardiomyopathies, which supports the hypothesis of the common molecular mechanisms with AD. A lot of potential shows the regulation of BACE1 activity through post-translational modifications. The interaction network of BACE1 and its phosphorylation enzyme CSNK1D functionally match the Circadian clock, p53, and Hedgehog signaling pathways. The regulation of BACE1 glycosylation could be achieved through N-acetylglucosamine transferases, α-(1→6)-fucosyltransferase, β-galactoside α-(2→6)-sialyltransferases, galactosyltransferases, and mannosidases suggested by the interaction network analysis of BACE1-MGAT3. The present analysis proposes possibilities for the alternative control of AD pathology.

SBA-15 Mesoporous Silica as Delivery Vehicle for rhBMP-2 Bone Morphogenic Protein for Dental Applications

(1) Background: A proposed approach to promote periodontal tissue regeneration in cases of peri-implantitis is the local administration of growth factors at the implant site. Recombinant human bone morphogenetic protein-2 (rh-BMP-2) can effectively promote bone regeneration and osseointegration and the development of appropriate carriers for its delivery is of paramount importance. The aim of the present study was to develop SBA-15 mesoporous nanoparticles (MSNs) with varying porosity, evaluate their biocompatibility with human Periodontal Ligament Cells (hPDLCs) and to investigate their effectiveness as carriers of rh-BMP-2. (2) Methods: SBA-15 type mesoporous silicas were synthesized via sol-gel reaction. The calcined SBA-15 samples were characterized by N2 porosimetry, Fourier transform-infrared spectrometry (FTIR), Scanning (SEM) and Transmission Electron Microscopy (TEM). Rh-BMP-2 loading and release kinetics were evaluated by UV spectroscopy. (3) Results: MSNs presented hexagonally arranged, tubular pores of varying length and diameter. Slightly higher loading capacity was achieved for SBA-15 with large pores that presented good hemocompatibility. MTT assay revealed no cytotoxic effects for all the tested materials, while SBA-15 with large pores induced a significant upregulation of cell viability at day 5. (4) Conclusions: SBA-15 MSNs may prove a valuable delivery platform towards the effective release of bone-inducing proteins.

Current Trends in IBD-Development of Mucosal-Based Biomarkers and a Novel Minimally Invasive Recoverable Sampling System

Despite recent developments in therapy for inflammatory bowel diseases (IBDs), there have been limited advances in diagnostic tools available to aid in disease management. A growing body of evidence suggests that there are important host-microbe interactions at the mucosal interface that modulate the inflammatory response in patients with IBD. Additionally, the importance of mucosal integrity and its disruption appears to be important in the pathophysiology and perpetuation of the disease. The ability to characterize this interface may provide valuable information for both disease monitoring and identification of new treatment targets. Endoscopy remains the primary tool for disease monitoring, and mucosal healing is the primary therapeutic target in IBD treatment. However, establishing mucosal healing requires repetitive endoscopic procedures, and endoscopy is limited by factors such as invasiveness, cost, and risk of adverse events. Moreover, the use of a bowel preparation for colonoscopies alters the mucus layer and thus perturbs evaluation of the host-microbe interaction. Stool sampling may also be inaccurate because it reflects the end state of metabolites and proteins, failing to take into account the degradation or alteration of substrates of interest by bacterial proteases and other enzymes during passage through the colon. A novel sampling capsule, called the Recoverable Sampling System (RSS), is being developed as a complementary tool to colonoscopy. The RSS is intended to be a platform for noninvasive autonomous sampling, preservation, handling, and storage of analytes of interest found in the gastrointestinal fluids. A proprietary preservative contained within the chambers of the capsule has been developed to stabilize DNA and proteins for ex vivo microbiome and metabolomics analyses. Surrogate markers such as SPP24 and GUCA2a have been identified to correlate with gut health, intestinal permeability, and inflammation and could be locally sampled by the RSS. The potential clinical utility of an RSS device is broad and would likely be able to guide therapy by allowing for more frequent disease monitoring, aiding in disease characterization, and facilitating in the identification of novel therapeutic targets.

Serum-derived extracellular vesicles inhibit osteoclastogenesis in active-phase patients with SAPHO syndrome

OBJECTIVE

Synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome is a rare chronic inflammatory disorder and the underlying pathogenesis is unclear. In this study, 88 SAPHO patients and 118 healthy controls were recruited to investigate the role of serum-derived extracellular vesicles (SEVs) in SAPHO syndrome.

METHODS

Quantitative proteomics was applied for SEVs proteome identification, and ELISA and Western blotting was performed to verify the results of mass spectrum data. In vitro osteoclastogenesis and osteogenesis assay was used to confirm the effects of SEVs on bone metabolism.

RESULTS

Tandem mass tagging-based quantitative proteomic analysis of SAPHO SEVs revealed differential expressed proteins involved in bone metabolism. Of these, serum amyloid A-1 (SAA1) and C-reactive protein (CRP) were upregulated. Higher SAA1 levels in SAPHO patients were confirmed by ELISA. In addition, SAA1 levels were positively correlated with CRP, an inflammatory marker related to the condition of patients. In vitro celluler studies confirmed that SAPHO SEVs inhibited osteoclastogenesis in patients mainly in the active phase of the disease. Further analysis demonstrated that Nucleolin was upregulated in osteoclasts of active-phase patients under SAPHO SEVs stimulation.

CONCLUSION

In this study, we identified SAA1 as an additional inflammation marker that can potentially assist the diagnosis of SAPHO syndrome, and speculated that Nucleolin is a key regulator of osteoclastogenesis in active-phase patients.

Secreted Phosphoprotein 24 is a Biomarker of Mineral Metabolism

The 24 kD form of secreted phosphoprotein (SPP-24), a cytokine-binding bone matrix protein with various truncated C-terminal products, is primarily synthesized by the liver. SPP-24 shares homology with fetuin-A, a potent vascular and soft tissue calcification inhibitor and SPP-24 is one component of calciprotein particles (CPPs), a circulating fetuin-mineral complex. The limited molecular evidence to date suggests that SPP-24 may also function as an inhibitor of bone formation and ectopic vascular calcification, potentially through bone morphogenic protein 2 (BMP-2) and Wnt-signaling mediated actions. The C-terminal products of SPP-24 bind to BMP-2 and attenuate BMP-2-induced bone formation. The aim of this study was to assess circulating SPP-24 in relation to kidney function and in concert with markers of mineral metabolism in humans. SPP-24 was measured in the serum of total of 192 subjects using ELISA-based measurements. Subjects were participants of one of two cohorts: (1) mGFR Cohort (n = 80) was participants of a study of measured GFR (mGFR) using inulin urinary clearance, recruited mostly from a chronic kidney disease clinic with low-range kidney function (eGFR 38.7 ± 25.0 mL/min/1.73 m²) and (2) CaMOS Cohort (n = 112) was a subset of randomly selected, community-dwelling participants of year 10 of the Canadian Multicentre Osteoporosis Study with eGFR in the normal range of 75.0 ± 15.9 mL/min/1.73 m². In the combined cohort, the mean SPP-24 was 167.7 ± 101.1 ng/mL (range 33.4-633.6 ng/mL). The mean age was 66.5 ± 11.3, 57.1% female and mean eGFR (CKD-EPI) was 59.9 ± 27.0 mL/min/1.73 m² (range 8-122 mL/min/1.73 m²). There was a strong inverse correlation between SPP-24 and eGFR (R = - 0.58, p < 0.001) that remained after adjustment for age. Following adjustment for age, eGFR, and sex, SPP-24 was significantly associated with phosphate (R = - 0.199), PTH (R = 0.298), and the Wnt-signaling inhibitor Dickkopf-related protein 1 (R = - 0.156). The results of this study indicate that SPP-24 is significantly altered by kidney function and is the first human data linking levels of SPP-24 to other biomarkers involved in mineral metabolism. Whether there is a role for circulating SPP-24 in bone formation and ectopic mineralization requires further study.

Spp24 is associated with endocytic signalling, lipid metabolism, and discrimination of tissue integrity for 'leaky-gut' in inflammatory bowel disease

Epithelial barrier injury allows contaminants to cross-over into the blood stream and trigger an inflammatory response, contributing to inflammatory bowel disease (IBD). Currently there is no single test that can reliably diagnose intestinal mucosal barrier function or measure impaired epithelial cell integrity associated with increasing permeability. Here, we assess the association between serum proteins and small intestinal permeability as detected by confocal laser endomicroscopy (CLE); in particular the known IBD marker—secreted phosphoprotein 24 (SPP24) and its binding partners; and use developed monoclonal antibodies to assess the role of SPP24 in mucosal healing. Sera were obtained from 28 IBD patients and non-IBD controls undergoing CLE with scores ranging from low to high permeability, as well as active ulcerative colitis from 53 patients undergoing fecal microbiota transplant therapy (FMT). Higher permeability associated with altered lipid metabolism, heightened innate immune response and junctional protein signalling in UC patients. A correlation between increasing leak and SPP24 peptide was observed. There is a strong indication of the novel role of SPP24 in gut barrier dysfunction particularly in ulcerative colitis. Its correlation to the established CLE for monitoring permeability has the potential to provide a blood based parallel to monitor and guide therapy more readily across a broad spectrum of illnesses for which ‘leak’ dominates the pathology.

Efficient delivery of recombinant human bone morphogenetic protein (rhBMP-2) with dextran sulfate-chitosan microspheres

Bone morphogenetic protein-2 (BMP-2) serves an important role in the development of bone and cartilage. However, administration of BMP-2 protein alone by intravenous delivery is not very effective. Sustained delivery of stabilized BMP-2 by carriers has been proven necessary to improve the osteogenesis effect of BMP-2. The present study constructed a novel drug delivery system using dextran sulfate (DS)-chitosan (CS) microspheres and investigated the efficiency of the delivery system on recombinant human bone morphogenetic protein (rhBMP-2). The microsphere morphology, optimal ratio of DS/CS/rhBMP-2, and drug loading rate and entrapment efficiency of rhBMP-2 CS nanoparticles were determined. L929 cells were used to evaluate the cytotoxicity and effect of DS/CS/rhBMP-2 microspheres on cell proliferation. Differentiation study was conducted using bone marrow mesenchymal stem cells (BMSCs-C57) cells treated with DS/CS/rhBMP-2 microspheres or the control microspheres. The DS/CS/rhBMP-2 microspheres delivery system was successfully established. Subsequent complexation of rhBMP-2-bound DS with polycations afforded well defined microspheres with a diameter of ~250 nm. High protein entrapment efficiency (85.6%) and loading ratio (47.245) µg/mg were achieved. Release of rhBMP-2 from resultant microspheres persisted for over 20 days as determined by ELISA assay. The bioactivity of rhBMP-2 encapsulated in the CS/DS microsphere was observed to be well preserved as evidenced by the alkaline phosphatase activity assay and calcium nodule formation of BMSCs-C57 incubated with rhBMP-2-loaded microspheres. The results demonstrated that microspheres based on CS-DS polyion complexes were a highly efficient vehicle for delivery of rhBMP-2 protein. The present study may provide novel orientation for bone tissue engineering for repairing and regenerating bone defects.

Secreted phosphoprotein 24kD (Spp24) inhibits growth of hepatocellular carcinoma in vivo

Several studies have shown that secreted phosphoprotein 24kD (Spp24) inhibits tumor growth. However, the effects of spp24 on hepatocellular carcinoma are not quite clear. In this study, we observed the inhibitory effect of spp24 on hepatocellular carcinoma in vivo. A subcutaneous hepatocellular carcinoma mice model was established by using Hep G2 cells. After sacrifice at day 40, tumor growth was assessed and tumor cell apoptosis and tumor cells proliferation were assessed by TUNEL assay and immunochemical analysis, respectively. BMP2 slightly stimulated the subcutaneous tumor growth compared with the control. Spp24 significantly inhibited the tumor growth and also abolished the BMP2-induced tumor growth (p<0.05). TUNEL assay and immunochemical analysis further showed that spp24 could enhance tumor cell apoptosis and inhibit cell proliferation (p<0.01). Our data show that spp24 can inhibit the growth of hepatocellular carcinoma. Spp24 may have great potential for cancer treatment.

A carboxy terminal BMP/TGF-β binding site in secreted phosphoprotein 24 kD independently affects BMP-2 activity

Secreted phosphoprotein 24 kD (spp24) is a bone matrix protein isolated during attempts to identify osteogenic proteins. It is not osteogenic but performs other important roles in the regulation of bone metabolism, at least in part, by binding to and affecting the activity of members of the BMP/TGF-β family of cytokines. Spp24 exists in a number of forms that preserve the N-terminus and are truncated at the C-terminus. The hypothesized cytokine binding domain is present within the cystatin domain which is preserved in all of the N-terminal products. In this report, we describe a C-terminal fragment that is distinct from the cystatin domain and which independently binds to BMP-2 and TGF-β. This fragment inhibited BMP-2 activity in an ectopic bone forming assay. A shorter C-terminal product did not inhibit BMP-2 activity but improved bone quality induced by BMP-2 and produced increased calcium deposition outside of bone. Spp24 has been used to develop several potential therapeutic proteins. These results provide more information on the function of spp24 and provide other materials that can be exploited for clinical interventions.

Spp24 derivatives stimulate a Gi-protein coupled receptor-Erk1/2 signaling pathway and modulate gene expressions in W-20-17 cells

Secreted phosphoprotein 24 kDa (Spp24) is an apatite- and BMP/TGF-β cytokine-binding phosphoprotein found in serum and many tissues, including bone. N-terminally intact degradation products ranging in size from 14 kDa to 23 kDa have been found in bone. The cleavage sites in Spp24 that produce these short forms have not been definitively identified, and the biological activities and mechanisms of action of Spp24 and its degradation products have not been fully elucidated. We found that the C-terminus of Spp24 is labile to proteolysis by furin, kallikrein, lactoferrin, and trypsin, indicating that both extracellular and intracellular proteolytic events could account for the generation of biologically-active Spp18, Spp16, and Spp14. We determined the effects of these truncation products on kinase-mediated signal transduction, gene expression, and osteoblastic differentiation in W-20-17 bone marrow stromal cells cultured in basal or pro-osteogenic media. After culturing for five days, all forms inhibited BMP-2-stimulated osteoblastic differentiation, assessed as induction of alkaline phosphatase activity, in basal, but not pro-osteogenic media. After 10 days, they also inhibited BMP-2-stimulated mineral deposition in pro-osteogenic media. Spp24 had no effect on Erk1/2 phosphorylation, but Spp18 stimulated short-term Erk1/2, MEK 1/2, and p38 phosphorylation. Pertussis toxin and a MEK1/2 inhibitor ablated Spp18-stimulated Erk 1/2 phosphorylation, indicating a role for Gi proteins and MEK1/2 in the Spp18-stimulated Erk1/2 phosphorylation cascade. Truncation products, but not full-length Spp24, stimulated RUNX2, ATF4, and CSF1 transcription. This suggests that Spp24 truncation products have effects on osteoblastic differentiation mediated by kinase pathways that are independent of exogenous BMP/TGF-β cytokines.

Low Mass Blood Peptides Discriminative of Inflammatory Bowel Disease (IBD) Severity: A Quantitative Proteomic Perspective

Breakdown of the protective gut barrier releases effector molecules and degradation products into the blood stream making serum and plasma ideal as a diagnostic medium. The enriched low mass proteome is unexplored as a source of differentiators for diagnosing and monitoring inflammatory bowel disease (IBD) activity, that is less invasive than colonoscopy. Differences in the enriched low mass plasma proteome (<25 kDa) were assessed by label-free quantitative mass-spectrometry. A panel of marker candidates were progressed to validation phase and "Tier-2" FDA-level validated quantitative assay. Proteins important in maintaining gut barrier function and homeostasis at the epithelial interface have been quantitated by multiple reaction monitoring in plasma and serum including both inflammatory; rheumatoid arthritis controls, and non-inflammatory healthy controls; ulcerative colitis (UC), and Crohn's disease (CD) patients. Detection by immunoblot confirmed presence at the protein level in plasma. Correlation analysis and receiver operator characteristics were used to report the sensitivity and specificity. Peptides differentiating controls from IBD originate from secreted phosphoprotein 24 (SPP24, p = 0.000086, 0.009); whereas those in remission and healthy can be differentiated in UC by SPP24 (p = 0.00023, 0.001), α-1-microglobulin (AMBP, p = 0.006) and CD by SPP24 (p = 0.019, 0.05). UC and CD can be differentiated by Guanylin (GUC2A, p = 0.001), and Secretogranin-1 (CHGB p = 0.035). Active and quiescent disease can also be differentiated in UC and CD by CHGB (p ≤ 0.023) SPP24 (p ≤ 0.023) and AMBP (UC p = 0.046). Five peptides discriminating IBD activity and severity had very little-to-no correlation to erythrocyte sedimentation rate, C-reactive protein, white cell or platelet counts. Three of these peptides were found to be binding partners to SPP24 protein alongside other known matrix proteins. These proteins have the potential to improve diagnosis and evaluate IBD activity, reducing the need for more invasive techniques. Data are available via ProteomeXchange with identifier PXD002821.

Secreted phosphoprotein 24 kD (Spp24) inhibits growth of human pancreatic cancer cells caused by BMP-2

The emerging role of bone morphogenetic proteins (BMPs) in the initiation and progression of multiple cancers has drawn great attention in cancer research. In this study, we report that BMP-2 can promote the proliferation of the pancreatic tumor cell line, PANC-1. Secreted phosphoprotein 24 kD (Spp24), a BMP binding protein, did not affect the proliferation of the cells but promoted the apoptosis of the cells in vitro. In a xeneograft tumor model using PANC-1 cells, BMP-2 dramatically promoted tumor growth, while Spp24 not only abolished the effect of BMP-2, but also dramatically induced tumor shrinking when used alone. Activation of Smad1/5/8 participated in this process as demonstrated by immunohistochemical staining of phosphorylated Smad 1/5/8. We conclude that Spp24 can be developed into a therapeutic agent that could be employed in clinical situations where the inhibition of BMPs and related proteins is advantageous.

Quercetin promotes the osteogenic differentiation of rat mesenchymal stem cells via mitogen-activated protein kinase signaling

The aim of the present study was to investigate the effects of quercetin on the mitogen-activated protein kinase (MAPK) signaling pathway in the osteogenic differentiation of rat mesenchymal stem cells (MSCs). A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and an alkaline phosphatase (ALP) assay were used to determine the effects of quercetin (concentrations of 0.1, 1 and 10 µmol/l) on the proliferation and differentiation of MSCs and the expression of ALP, respectively. In addition, through the introduction of inhibitors of p38 MAPK, extracellular signal-regulated kinase (ERK)1/2 and c-Jun NH₂-terminal kinase (JNK), the effects of quercetin on the proteins, ALP, collagen type I (COL I) and bone γ-carboxyglutamate protein (BGP), which are indicators of osteogenic differentiation, were investigated. Immunoblotting was performed to determine the phosphorylation levels of p38 MAPK, ERK1/2 and JNK, while fluorescent quantitative polymerase chain reaction was used to determine the mRNA expression levels of transforming growth factor (TGF)-β1, bone morphogenetic protein (BMP)-2 and core binding factor (CBF)α1. At all the concentrations tested, the concentrations of 10, 1 and 0.1 µmol/l quercetin were shown to promote the differentiation of MSCs and the expression of ALP, in which the concentration of 10 µmol/l was optimal. When compared with the control group, the phosphorylation levels of p38 MAPK, ERK1/2 and JNK, the protein expression levels of ALP, COL I and BGP, and the mNRA expression levels of TGF-β1, BMP-2 and Cbfα1 were increased in the quercetin-treated group. However, with the introduction of inhibitors, the levels of phosphorylated p38 MAPK, ERK1/2 and JNK, and the protein expression levels of ALP, COL I and BGP decreased. Furthermore, the mRNA expression levels of TGF-β1, BMP-2 and CBFα1 decreased in the quercetin + SP600125 (inhibitor of JNK) and quercetin + PD98059 (inhibitor of ERK1/2) groups. Therefore, quercetin was demonstrated to promote the osteogenic differentiation of MSCs by activating the MAPK signaling pathway. The ERK1/2 and JNK signaling pathways regulate the expression of TGF-β1, BMP-2 and CBFα1. Thus, activation of the ERK1/2 and JNK signaling pathways may play a leading role in the quercetin-promoted osteogenic proliferation and differentiation of MSCs.

Identification of plasma protein markers common to patients with malignant tumour and Abnormal Savda in Uighur medicine: a prospective clinical study

Background

Traditional Uighur medicine shares an origin with Greco-Arab medicine. It describes the health of a human body as the dynamic homeostasis of four normal Hilits (humours), known as Kan, Phlegm, Safra, and Savda. An abnormal change in one Hilit may cause imbalance among the Hilits, leading to the development of a syndrome. Abnormal Savda is a major syndrome of complex diseases that are associated with common biological changes during disease development. Here, we studied the protein expression profile common to tumour patients with Abnormal Savda to elucidate the biological basis of this syndrome and identify potential biomarkers associated with Abnormal Savda.

Methods

Patients with malignant tumours were classified by the diagnosis of Uighur medicine into two groups: Abnormal Savda type tumour (ASt) and non-Abnormal Savda type tumour (nASt), which includes other syndromes. The profile of proteins that were differentially expressed in ASt compared with nASt and normal controls (NC) was analysed by iTRAQ proteomics and evaluated by bioinformatics using MetaCore™ software and an online database. The expression of candidate proteins was verified in all plasma samples by enzyme-linked immunosorbent assay (ELISA).

Results

We identified 31 plasma proteins that were differentially expressed in ASt compared with nASt, of which only 10 showed quantitatively different expression between ASt and NC. Bioinformatics analysis indicated that most of these proteins are known biomarkers for neoplasms of the stomach, breast, and lung. ELISA detection showed significant upregulation of plasma SAA1 and SPP24 and downregulation of PIGR and FASN in ASt compared with nASt and NC (p < 0.05).

Conclusions

Abnormal Savda may be causally associated with changes in the whole regulation network of protein expression during carcinogenesis. The expression of potential biomarkers might be used to distinguish Abnormal Savda from other syndromes.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-015-0526-6) contains supplementary material, which is available to authorized users.

Secreted phosphoprotein 24 kD inhibits nerve root inflammation induced by bone morphogenetic protein-2

BACKGROUND CONTEXT

Bone morphogenetic protein-2 (BMP-2) has been used to successfully promote spine fusion, but side-effects including nerve inflammation have been observed.

PURPOSE

To investigate the direct neurotoxic effects of BMP-2 and test the hypotheses that the use of BMP binding proteins, such as secreted phosphoprotein 24 kD (Spp24), can reduce or eliminate these effects.

STUDY DESIGN

In vitro experiments and in vivo analysis in a rodent model.

METHODS

In vitro, dorsal root ganglion cells were cultured in the presence of BMP-2 with and without Spp24 and calcitonin gene-related peptide and Substance P, markers of neuroinflammation, were measured by immunohistochemistry. In vivo, rats underwent a left-sided laminotomy at L5 to expose the S1 nerve root and were randomized into four different groups according to the intervention at the laminotomy site: collagen sponge only (no BMP-2 or Spp24), BMP-2 in a collagen sponge only, BMP-2 in a collagen sponge+an empty collagen sponge to act as a barrier, and BMP-2 in a collagen sponge+Spp24 in a collagen sponge to act as a barrier. Functional evaluation was done using the Basso, Beattie, and Bresnahan scale and immunohistochemical analyses were performed using calcitonin gene-related peptide and Substance P staining.

RESULTS

The neuroinflammatory effects of BMP-2 in vitro were ameliorated by the addition of Spp24. Similarly, in vivo, Spp24 reduced the expression of markers on neuroinflammation in animals treated with BMP-2 and also improved the function after BMP-2 administration.

CONCLUSIONS

These results confirm that BMP binding proteins have great potential as adjuvant therapies to limit BMP-2 related side-effects in spine surgery.