Association of endothelin-1 expression and cartilaginous endplate degeneration in humans

Anticancer Mechanisms and Potential Anticancer Applications of Antimicrobial Peptides and Their Nano Agents

Traditional chemotherapy is one of the main methods of cancer treatment, which is largely limited by severe side effects and frequent development of multi-drug resistance by cancer cells. Antimicrobial peptides (AMPs) with high efficiency and low toxicity, as one of the most promising new drugs to replace chemoradiotherapy, have become a current research hotspot, attracting the attention of worldwide researchers. AMPs are natural-source small peptides from the innate immune system, and certain AMPs can selectively kill a broad spectrum of cancer cells while exhibiting less damage to normal cells. Although it involves intracellular mechanisms, AMPs exert their anti-cancer effects mainly through membrane destruction effect; thus, AMPs also hold unique advantages in fighting drug-resistant cancer cells. However, the poor stability and hemolytic toxicity of peptides limit their clinical application. Fortunately, functionalized nanoparticles have many possibilities in overcoming the shortcomings of AMPs, which provides a huge prospect for better application of AMPs. In this paper, we briefly introduce the characteristics and different sources of AMPs, review and summarize the mechanisms of action and the research status of AMPs used as an anticancer therapy, and finally focus on the further use of AMPs nano agents in the anti-cancer direction.

Pathogenesis and therapeutic implications of matrix metalloproteinases in intervertebral disc degeneration: A comprehensive review

Intervertebral disc (IVD) degeneration (IDD) is a common disorder that affects the spine and is a major cause of lower back pain (LBP). The extracellular matrix (ECM) is the structural foundation of the biomechanical properties of IVD, and its degradation is the main pathological characteristic of IDD. Matrix metalloproteinases (MMPs) are a group of endopeptidases that play an important role in the degradation and remodeling of the ECM. Several recent studies have shown that the expression and activity of many MMP subgroups are significantly upregulated in degenerated IVD tissue. This upregulation of MMPs results in an imbalance of ECM anabolism and catabolism, leading to the degradation of the ECM and the development of IDD. Therefore, the regulation of MMP expression is a potential therapeutic target for the treatment of IDD. Recent research has focused on identifying the mechanisms by which MMPs cause ECM degradation and promote IDD, as well as on developing therapies that target MMPs. In summary, MMP dysregulation is a crucial factor in the development of IDD, and a deeper understanding of the mechanisms involved is needed to develop effective biological therapies that target MMPs to treat IDD.

Endothelin-1 reduces catabolic activity of human mesenchymal stem/stromal cells during chondro- and osteo-lineage differentiation

Human mesenchymal stem/stromal cells (hMSCs) reside in a vascularized microenvironment and experience a host of blood vessel secretions, including endothelin-1 (ET1). Previously, our group has demonstrated improved induction of osteogenesis and chondrogenesis in hMSCs through an ET1-induced increase in production of anabolic factors. The current study explores effects of ET1 on catabolic factors secreted by hMSCs during chondrogenesis and osteogenesis. Cell proliferation and extracellular matrix (ECM) deposition were also explored. Our results demonstrated that ET1 reduced mRNA transcript levels of MMP2, MMP13, ADAMTS4, and ADAMTS5 in chondrogenic hMSCs, and MMP13 and ADAMTS5 in osteogenic hMSCs. Furthermore, ET1-treated chondrogenic and osteogenic hMSCs showed more intense stains for Alcian blue and Alizarin red S, respectively, than control cells. Immunocytochemical results demonstrated that the ET1-mediated reduction of MMP13 could be reversed through blocking ET1 induction. Overall, our findings indicate that hMSCs treated with ET1 during chondrogenic or osteogenic induction attenuate catabolic activities of the cell to reduce ECM degradation, suggesting that it may be beneficial to use ET1 to enhance hMSC differentiation and protect newly synthesized ECM from degradation.

Serum endothelin-1 levels, radiographic and ultrasonographic evaluations, and clinical parameters in patients with knee and/or hand osteoarthritis

BACKGROUND

Endothelin-1 (ET-1) is one of the probable inflammatory factors stimulating cartilage degradation in osteoarthritis (OA) pathogenesis.

OBJECTIVE

To assess ET-1 level in OA and its correlation with radiographic findings, cartilage morphology and clinical parameters.

METHODS

One hundred and thirty-nine subjects (89 OA, 50 controls) were included in this cross-sectional study. Both knee and hand joints of the participants were examined using plain radiography and ultrasound imaging by which distal femoral cartilage thickness/grading and second metacarpophalangeal cartilage thickness were assessed. Subjects were evaluated for pain and functional status using visual analogue scale, Western Ontario and McMaster Universities Arthritis Index and Duruöz Hand Index.

RESULTS

Serum ET-1 levels were higher in the OA group than the control group. Serum ET-1 levels were not correlated with cartilage thickness in patients with OA. Serum ET-1 levels were not correlated with either pain or other clinical parameters in the knee OA group and in the hand OA group.

CONCLUSION

This is the first study evaluating the relationship between serum ET-1 levels and cartilage morphology and clinical parameters, which did not show any conclusive result. Future studies, overcoming the limitations of this study, might provide a better understanding of the role of ET-1 in the pathogenesis of OA.

Endothelin-1 Activates the Notch Signaling Pathway and Promotes Tumorigenesis in Giant Cell Tumor of the Spine

STUDY DESIGN

Experimental study.

OBJECTIVE

To examine the role of endothelin-1 (ET-1) and the Notch signaling pathway in giant cell tumor (GCT) of the spine.

SUMMARY OF BACKGROUND DATA

Previously published studies have shown that the Notch signaling pathway has a role in tumor invasion and that ET-1 is involved in tumor invasion and angiogenesis. However, the roles of both Notch signaling and ET-1 in GCT of the spine remain unknown.

METHODS

Expression of ET-1 in tissue samples from patients with spinal GCT, and adjacent normal tissue, were analyzed by immunohistochemistry and western blot. GCT stromal cells (GCTSCs) were isolated and ET-1 expression was demonstrated by immunofluorescence. Cell viability and cell migration of GCTSCs and human vascular endothelial cells following ET-1 treatment were assessed using the cell counting kit-8 assay and a transwell assay. Receptor activator of nuclear factor kappa-B ligand (RANKL) and osteoprotegerin (OPG) mRNA expression was determined following ET-1 treatment of GCTSCs using quantitative real-time polymerase chain reaction. In GCTSCs treated with ET-1 and the ET-1 signaling antagonist, BQ-123, levels of cyclin D1, vascular endothelial growth factor, matrix metalloproteinase-2 and -9 (MMP-2 and MMP-9), Jagged1, Hes1, Hey2, and Notch intracellular domain were examined by western blot.

RESULTS

Compared with normal adjacent tissue, ET-1 was highly expressed in GCT tissue. In GCTSCs studied in vitro, treatment with ET-1 significantly increased GCTSC and human vascular endothelial cells growth and migration and increased the expression of RANKL and OPG, meanwhile the ratio of RANKL/OPG was increased, in GCTSCs, it upregulated the production of cyclin D1, vascular endothelial growth factor, MMP-2, MMP-9, Jagged1, Hes1, Hey2, and Notch intracellular domain expression in a dose-dependent manner. Treatment with BQ-123 reversed these effects.

CONCLUSION

In GCT of the spine, ET-1 showed increased expression. In cultured GCTSCs, ET-1 treatment activated the Notch signaling pathway.

LEVEL OF EVIDENCE

2.

Endothelial cells and endothelin‑1 promote the odontogenic differentiation of dental pulp stem cells

It has been established that dental pulp stem cells (DPSCs) serve an important role in the restoration and regeneration of dental tissues. DPSCs are present in blood vessels and also exist in the vessel microenvironment in vivo and have a close association with endothelial cells (ECs). The present study aimed to evaluate the influence of ECs and their secretory product endothelin-1 (ET-1) on the differentiation of DPSCs. In the present study, cells were divided into four groups: i) a DPSC-only control group; ii) a DPSC with ET-1 administration group; iii) a DPSC and human umbilical vein endothelial cell (HUVEC) direct co-culture group; and iv) a DPSC and HUVEC indirect co-culture group using a Transwell system. Reverse transcription-quantitative polymerase chain reaction was used to detect the expression of the odontoblastic differentiation-associated genes, including dentin sialoprotein (DSP) and dentin matrix acidic phosphoprotein 1 (DMP-1) at days 4, 7, 14 and 21. Alizarin Red S staining, immunofluorescence and western blot analyses were also conducted to assess the differentiation of the DPSCs in each group. The highest expression levels of odontoblastic differentiation-associated genes were observed on day 7 and in the two co-culture groups were increased compared with the DPSC-only and DPSC + ET-1 culture groups at all four time points. However, expression levels in the DPSC + ET-1 group were not downregulated as notably as in the co-culture groups on days 14 and 21. The Transwell group exhibited the greatest ability for odontoblastic differentiation compared with the other groups according to staining with Alizarin Red S, immunofluorescence and western blot analysis results. According to the results of the present study, the culture solution with HUVECs affected the differentiation of DPSCs. In addition, ET-1 may promote the odontoblastic differentiation of DPSCs.

Comparative and quantitative proteomic analysis of normal and degenerated human annulus fibrosus cells

Degeneration of the intervertebral disc (IVD) is a major chronic medical condition associated with back pain. To better understand the pathogenesis of IVD degeneration, we performed comparative and quantitative proteomic analyses of normal and degenerated human annulus fibrosus (AF) cells and identified proteins that are differentially expressed between them. Annulus fibrosus cells were isolated and cultured from patients with lumbar disc herniation (the experimental group, degenerated AF cells) and scoliosis patients who underwent orthopaedic surgery (the control group, normal AF cells). Comparative proteomic analyses of normal and degenerated cultured AF cells were carried out using 2-D electrophoresis, mass spectrometric analyses, and database searching. Quantitative analyses of silver-stained 2-D electrophoresis gels of normal and degenerated cultured AF cells identified 10 protein spots that showed the most altered differential expression levels between the two groups. Among these, three proteins were decreased, including heat shock cognate 71-kDa protein, glucose-6-phosphate 1-dehydrogenase, and protocadherin-23, whereas seven proteins were increased, including guanine nucleotide-binding protein G(i) subunit α-2, superoxide dismutase, transmembrane protein 51, adenosine receptor A3, 26S protease regulatory subunit 8, lipid phosphate phosphatase-related protein, and fatty acyl-crotonic acid reductase 1. These differentially expressed proteins might be involved in the pathophysiological process of IVD degeneration and have potential values as biomarkers of the degeneration of IVD.

Establishment of intervertebral disc degeneration model induced by ischemic sub-endplate in rat tail

BACKGROUND CONTEXT

Microcirculatory dysfunction of the sub-endplate is considered to reduce nutrient supply to the intervertebral disc (IVD); however, direct interruption or destruction of blood vessels in the bone marrow of the vertebrae body adjacent to the endplate has not yet been described, especially with regard to the calcification and ossification of the cartilaginous endplate occurring during IVD degeneration.

PURPOSE

The purpose of the study was to evaluate the causal relationship between IVD degeneration and blocking of the main blood supply gateway through the endplate.

STUDY DESIGN/SETTING

The study describes a new IVD degeneration model induced by ischemic sub-endplate.

PATIENT SAMPLE

A total of 40 Sprague-Dawley rats were included in the study group.

OUTCOME MEASURES

To assess disc height, a radiograph was taken each month for 4 months. Changes in endplate, nucleus pulposus (NP), and annulus fibrosus (AF) were evaluated by histochemical and immunohistochemical staining to detect IVD degeneration.

METHODS

Injection of 30 μL absolute ethanol into the IVD of rat tail at Co7/Co8 was used to induce injury. Controls were injected with 30 μL of phosphate-buffered saline into the IVD at Co8/Co9.

RESULTS

In the ethanol-injected group, disc height gradually decreased and bone sclerosis developed in the endplate. In the NP, cell transformation occurred, changing from predominantly vacuolar cells to chondrogenic cells and eventually fibrocartilaginous cells, along with fibrosis of the NP. As degeneration progressed, the AF developed disordered morphology and rough lamellae, and eventually ruptures and fibrosis. The extent of degeneration increased gradually over time, while the wavy tidemark of the growth plate regressed, and eventually disappeared. Initially positive collagen type II staining gradually decreased on the ischemic side of the sub-endplate. Except at the 3-month time point, expression of collagen type II, aggrecan, and Sox-9 in NP decreased gradually as degeneration progressed, compared with the control group.

CONCLUSIONS

This model successfully reproduced IVD degeneration, which could be used for etiological studies on IVD degeneration and investigation of nutrient supply disturbance, and may provide a theoretical foundation for clinical intervention and therapy for IVD degeneration in the future.

The emerging role of endothelin-1 in the pathogenesis of subchondral bone disturbance and osteoarthritis

Mounting evidence suggests reconceptualizing osteoarthritis (OA) as an inflammatory disorder. Trauma and obesity, the common risk factors of OA, could trigger the local or systemic inflammatory cytokines cascade. Inflammatory bone loss has been well documented; yet it remains largely unknown about the link between the inflammation and hypertrophic changes of subchondral bone seen in OA, such as osteophytosis and sclerosis. Amid a cohort of inflammatory cytokines, endothelin-1 (ET-1) could stimulate the osteoblast-mediated bone formation in both physiological (postnatal growth of trabecular bone) and pathological conditions (bone metastasis of prostate or breast cancer). Also, ET-1 is known as a mitogen and contributes to fibrosis in various organs, e.g., skin, liver, lung, kidney heart and etc., as a result of inflammatory or metabolic disorders. Subchondral bone sclerosis shared the similarity with fibrosis in terms of the overproduction of collagen type I. We postulated that ET-1 might have a hand in the subchondral bone sclerosis of OA. Meanwhile, ET-1 was also able to stimulate the production of matrix metalloproteinase (MMP)-1 and 13 by articular chondrocytes and synoviocytes, by which it might trigger the enzymatic degradation of articular cartilage. Taken together, ET-1 signaling may play a role in destruction of bone-cartilage unit in the pathogenesis of OA; it warrants further investigations to potentiate ET-1 as a novel diagnostic biomarker and therapeutic target for rescue of OA.

Differential gene expression of human chondrocytes cultured under short-term altered gravity conditions during parabolic flight maneuvers

Background

Chondrocytes are the main cellular component of articular cartilage. In healthy tissue, they are embedded in a strong but elastic extracelluar matrix providing resistance against mechanical forces and friction for the joints. Osteoarthritic cartilage, however, disrupted by heavy strain, has only very limited potential to heal. One future possibility to replace damaged cartilage might be the scaffold-free growth of chondrocytes in microgravity to form 3D aggregates.

Results

To prepare for this, we have conducted experiments during the 20th DLR parabolic flight campaign, where we fixed the cells after the first (1P) and the 31st parabola (31P). Furthermore, we subjected chondrocytes to isolated vibration and hypergravity conditions. Microarray and quantitative real time PCR analyses revealed that hypergravity regulated genes connected to cartilage integrity (BMP4, MMP3, MMP10, EDN1, WNT5A, BIRC3). Vibration was clearly detrimental to cartilage (upregulated inflammatory IL6 and IL8, downregulated growth factors EGF, VEGF, FGF17). The viability of the cells was not affected by the parabolic flight, but showed a significantly increased expression of anti-apoptotic genes after 31 parabolas. The IL-6 release of chondrocytes cultured under conditions of vibration was not changed, but hypergravity (1.8 g) induced a clear elevation of IL-6 protein in the supernatant compared with corresponding control samples.

Conclusion

Taken together, this study provided new insights into the growth behavior of chondrocytes under short-term microgravity.

Electronic supplementary material

The online version of this article (doi:10.1186/s12964-015-0095-9) contains supplementary material, which is available to authorized users.

Assessment of circulatory and pulmonary endothelin-1 levels in a lavage-induced surfactant-depleted lung injury rabbit model with repeated open endotracheal suctioning and hyperinflation

AIMS

Endothelin-1 (ET-1) is a mediator of various physiological and pathological processes, including vascular inflammation, cell proliferation and vasoconstriction. Attenuation of ET action using ET-1 antagonists reduces pulmonary vascular leakage and inflammation in several models of lung injuries and experimental acute respiratory distress syndrome (ARDS). Based on these earlier reports, the current study investigates the patterns of ET-1 levels in circulation and pulmonary tissues in an experimental model of lavage-induced surfactant-depleted lung injury. Additionally, we also test the effects of open endotracheal suctioning (OES) and hyperinflation (HI) as recruitment maneuver following OES on ET-1 levels.

MAIN METHODS

Briefly, 24 Japanese white rabbits were anesthetized and intubated. Normal saline was instilled into the lung and washed mildly. After instillation, rabbits were ventilated at definite settings at a total duration of 3 hours. OES and HI were performed every 15 minutes from the beginning of the protocol.

KEY FINDINGS

Here, we show that both circulatory and pulmonary ET-1 levels increased in models with lung injury induced by saline lavage compared to healthy control group. No further aggravation in expression of pulmonary ET-1 was seen after OES and HI, although OES and HI worsened arterial hypoxygenation and severity of lung injury. In contrast, circulatory ET-1 levels significantly decreased after OES and HI but were not associated with blood pressure changes.

SIGNIFICANCE

We conclude that in a saline lavage-induced lung injury model, both circulatory and pulmonary ET-1 levels increased. Further, OES and HI exerted differential effects on ET-1 expression at both circulatory and pulmonary levels.