Zoledronate induces autophagic cell death in human umbilical vein endothelial cells via Beclin-1 dependent pathway activation

IL-17A is involved in the hyperplasia of blood vessels in local lesions of psoriasis by inhibiting autophagy

OBJECTIVE

Increased angiogenesis is a pathological feature of psoriasis, but the pathomechanisms of angiogenesis in psoriasis are not clear. Interleukin-17A (IL-17A) is the major effect factor in the pathogenesis of psoriasis. Our results showed that IL-17A can promote angiogenesis and cause endothelial cell inflammation. Autophagy plays an important role not only in regulating inflammation, but also in regulating angiogenesis. Whether angiogenesis in psoriasis is related to autophagy remains unclear. In this study, we treated human umbilical vein endothelial cells (HUVECs) with IL-17A to simulate increased angiogenesis to study whether increased angiogenesis in psoriasis is related to autophagy.

METHODS AND RESULTS

Our results showed that treatment of HUVECs with IL-17A significantly increased angiogenesis and expression levels of mRNA for multiple proinflammatory cytokines (CCL20, IL-8, CCL2, IL-6, and IL-1β) and, while decreasing intracellular levels of nitric oxide (NO) and NO synthase (NOS) activity. Moreover, IL-17A inhibited autophagy as shown that IL-17A significantly increased expression levels of LC3II and p62 proteins. Induction of autophagy ameliorated IL-17A-mediated inflammatory response and inhibited angiogenesis, accompanied by increased p-AMPKα(Thr172) and p-ULK1(Ser555) expression, and decreased p-mTOR(Ser2448) and p-ULK1(Ser757) expression. Furthermore, inhibition of either AMPK or lysosomal acidification completely overrode autophagy-induced changes in angiogenesis and NOS activity. Finally, induction of autophagy decreased apoptosis and caspase-3 activity in IL-17A-treated HUVECs.

CONCLUSIONS

These results showed that IL-17A is involved in angiogenesis and inflammatory response by inhibiting autophagy through AMPK signaling pathway, suggesting that autophagy may be a new therapeutic target for psoriasis.

New Dawn for Atherosclerosis: Vascular Endothelial Cell Senescence and Death

Endothelial cells (ECs) form the inner linings of blood vessels, and are directly exposed to endogenous hazard signals and metabolites in the circulatory system. The senescence and death of ECs are not only adverse outcomes, but also causal contributors to endothelial dysfunction, an early risk marker of atherosclerosis. The pathophysiological process of EC senescence involves both structural and functional changes and has been linked to various factors, including oxidative stress, dysregulated cell cycle, hyperuricemia, vascular inflammation, and aberrant metabolite sensing and signaling. Multiple forms of EC death have been documented in atherosclerosis, including autophagic cell death, apoptosis, pyroptosis, NETosis, necroptosis, and ferroptosis. Despite this, the molecular mechanisms underlying EC senescence or death in atherogenesis are not fully understood. To provide a comprehensive update on the subject, this review examines the historic and latest findings on the molecular mechanisms and functional alterations associated with EC senescence and death in different stages of atherosclerosis.

Could Local Application of Hypoxia Inducible Factor 1-α Enhancer Deferoxamine Be Promising for Preventing of Medication-Related Osteonecrosis of the Jaw?

This experimental study investigates the prophylactic effect of deferoxamine (DFO) on medication-related osteonecrosis of the jaw (MRONJ). Thirty-six female Sprague Dawley rats received zoledronic acid (ZA) for eight weeks to create an osteonecrosis model. DFO was locally applied into the extraction sockets with gelatin sponge (GS) carriers to prevent MRONJ. The specimens were histopathologically and histomorphometrically evaluated. Hypoxia-inducible factor 1-alpha (HIF-1α) protein levels in the extraction sockets were quantified. New bone formation rate differed significantly between groups (p = 0.005). Newly formed bone ratios in the extraction sockets did not differ significantly between the control group and the GS (p = 1), GS/DFO (p = 0.749), ZA (p = 0.105), ZA-GS (p = 0.474), and ZA-GS/DFO (p = 1) groups. While newly formed bone rates were higher in the ZA-GS and ZA-GS/DFO groups than in the ZA group, the differences were not significant. HIF-1α levels differed significantly between groups (p < 0.001) and were significantly higher in the DFO and ZA-GS/DFO groups than in the control group (p = 0.001 and p = 0.004, respectively). While HIF-1α levels were higher in the ZA-GS/DFO group than in the ZA group, the difference was not significant. While HIF-1α protein levels and new bone formation rate were elevated in the DFO-treated group, the effect was not significant. Further large-scale studies are needed to understand DFO’s preventative effects on MRONJ and the role of HIF-1α in MRONJ pathogenesis.

Impacts of bisphosphonates on the bone and its surrounding tissues: mechanistic insights into medication-related osteonecrosis of the jaw

Bisphosphonates are widely used as anti-resorptive agents for the treatment of various bone and joint diseases, including advanced osteoporosis, multiple myeloma, bone metastatic cancers, Paget's disease of bone, and rheumatoid arthritis. Bisphosphonates act as an anti-osteoclast via the induction of osteoclast apoptosis, resulting in a decreased rate of bone resorption. Unfortunately, there is much evidence to demonstrate that the long-term use of bisphosphonates is associated with osteonecrosis. The pathogenesis of osteonecrosis includes the death of osteoblasts, osteoclasts, and osteocytes. In addition, the functions of endothelial cells, epithelial cells, and fibroblasts are impaired in osteonecrosis, leading to disruptive angiogenesis, and delayed wound healing. Osteonecrosis is most commonly found in the jawbone and the term medication-related osteonecrosis of the jaw (MRONJ) has become the condition of greatest clinical concern among patients receiving bisphosphonates. Although surgical treatment is an effective strategy for the treatment of MRONJ, several non-surgical interventions for the attenuation of MRONJ have also been investigated. With the aim of increasing understanding around MRONJ, we set out to summarize and discuss the holistic effects of bisphosphonates on the bone and its surrounding tissues. In addition, non-surgical interventions for the attenuation of bisphosphonate-induced osteonecrosis were reviewed and discussed.

Medication-Related Osteonecrosis of the Jaws Initiated by Zoledronic Acid and Potential Pathophysiology

The aim of this systematic review is to present an up-to-date review of available publications investigating the cellular mechanisms initiating the development of medication-related osteonecrosis of the jaw caused by zoledronic acid. Electronic searches of MEDLINE/PubMed and Scopus were conducted on the 3 June 2019. A total of 804 publications were identified, of which 11 met the inclusion criteria and were, therefore, included in this study. All the included studies were in vitro studies investigating various human cells. The current review found that zoledronic acid in various concentrations increased apoptosis and decreased migration and proliferation of epithelial cells, fibroblasts, osteoblasts, endothelial cells and dental pulp stem cells, which can affect local tissue homeostasis. The consequences of zoledronic acid were found to be both time- and dose-dependent. The pathophysiology of medication-related osteonecrosis of the jaw is likely a multifactorial process involving prolonged wound healing, chronic inflammation and altered bone remodelling following the administration of zoledronic acid. Further research is needed to identify the exact pathophysiology to optimise management and treatment.

Titanium implant alters the effect of zoledronic acid on the behaviour of endothelial cells

OBJECTIVES

To evaluate the effect of zoledronic acid (ZA) on human umbilical vein endothelial cells (HUVECs) attached to different surfaces.

MATERIALS AND METHODS

A total of three groups were evaluated in this study: sandblasting and acid etching (SLA) + HUVECs; mechanically polished (MP) + HUVECs; and plastic cell culture plates + HUVECs. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, surface roughness and water contact angle were tested for titanium surface characterisation. ZA was added at different concentrations (0, 1, 10, 50 and 100 μM). Cell adhesion, proliferation, viability, apoptosis and gene expression were evaluated.

RESULTS

Mechanically polished and SLA surfaces showed negative effects on cell adhesion and proliferation and promoted cell apoptosis with 100 μM ZA (p < .05). The highest expression of intercellular adhesion molecule-1 (ICAM-1) and angiopoietin-1 was found on SLA surfaces (p < .01). The lowest expression of platelet-endothelial cell adhesion molecule-1 and ICAM-1 was found on MP surfaces (p < .05). A significant decrease in von Willebrand factor was detected on MP and SLA surfaces (p < .001).

CONCLUSIONS

Zoledronic acid has an anti-angiogenic effect on HUVECs attached to titanium implants, while the SLA surface might stimulate HUVECs to express angiogenic and adhesive factor genes despite ZA treatment.

Epidermal Growth Factor Reverses the Inhibitory Effects of the Bisphosphonate, Zoledronic Acid, on Human Oral Keratinocytes and Human Vascular Endothelial Cells In Vitro via the Epidermal Growth Factor Receptor (EGFR)/Akt/Phosphoinositide 3-Kinase (PI3K) Signaling Pathway

Background

Medication-related osteonecrosis of the jaw (MRONJ) is due to the direct effects of drug toxicity and the effects on angiogenesis. The aims of this study were to evaluate the effects of treatment with the bisphosphonate, zoledronic acid, on human oral keratinocytes (HOKs) and human umbilical vein endothelial cells (HUVECs) in vitro, and whether epidermal growth factor (EGF) could alter these effects.

Material/Methods

HOKs and HUVECs were incubated with zoledronic acid or EGF. Cell viability was assessed by the cell counting kit-8 (CCK-8), cell apoptosis was studied using Annexin-V conjugated to fluorescein isothiocyanate (FITC). Angiogenesis was studied by observing HUVEC tube formation and cell migrations using a transwell assay. A scratch wound assay investigated cell migration of HOKs. Western blot measured expression levels of phosphorylated epidermal growth factor receptor (EGFR), Akt, phosphoinositide 3-kinase (PI3K), the mechanistic target of rapamycin (mTOR), and endothelial nitric oxide synthase (eNOS).

Results

Zoledronic acid treatment (5 μmol/L) significantly inhibited cell viability and cell migration of HOKs and HUVECs and angiogenesis of HUVECS (P<0.05); EGF partially reversed these effects (P<0.05). Zoledronic acid treatment of HOKs and HUVECs had no significant effects on apoptosis (P>0.05), but significantly reduced expression levels of p-EGFR, p-Akt, p-PI3K, p-mTOR), and p-eNOS (P<0.05); EGF partially reversed these effects and increased the expression levels (P<0.05).

Conclusions

EGF partially reversed the effects of the bisphosphonate, zoledronic acid, on HOKs and HUVECs in vitro via the EGFR/Akt/PI3K signaling pathway. Further studies are required to determine the effects of EGF on MRONJ including bisphosphonate-related osteonecrosis of the jaw.

Pathogenesis of medication-related osteonecrosis of the jaw: a comparative study of in vivo and in vitro trials

Objective This study was performed to determine whether the results of prevailing in vivo and in vitro studies offer a reliable model for investigation of medication-related osteonecrosis of the jaw (MRONJ). Methods Embase, Medline, and the Cochrane Library were searched for articles published from September 2003 to June 2017 involving experimental approaches to the pathogenesis of MRONJ. In vivo and in vitro trials were analyzed with respect to the scientific question, study design, methodology, and results. Results Of 139 studies, 87, 46, and 6 conducted in vivo, in vitro, and both in vivo and in vitro experiments, respectively. Rats, mice, dogs, minipigs, sheep, and rabbits were the preferred animal models used. Osteoblasts, osteoclasts, fibroblasts, keratinocytes, macrophages, and human umbilical vein endothelial cells were the preferred cell types. Zoledronate, alendronate, ibandronate, and risedronate were the most frequent bisphosphonates used. MRONJ was most reliably induced in minipigs because of the close relationship with human bone physiology. In vitro studies showed that reduced viability, growth, and migration of cells in the bone and soft tissues were causative for MRONJ. Other than exposed jawbone after tooth extraction, no reliable cofactors were found. Conclusion The minipig is the most suitable animal model for MRONJ.

Upregulation of DAPK2 ameliorates oxidative damage and apoptosis of placental cells in hypertensive disorder complicating pregnancy by suppressing human placental microvascular endothelial cell autophagy through the mTOR signaling pathway

Death-associated protein kinase 2 (DAPK2) has indicated functional roles in cellular processes, including survival, apoptosis, and autophagy. This study is aimed to identify the effect of DAPK2 on oxidative damage and apoptosis of placental cells in hypertensive disorder complicating pregnancy (HDCP) through mTOR pathway. Microarray-based gene expression analysis was performed to predict the differentially expressed genes related to HDCP. To investigate the specific mechanism of DAPK2 in HDCP cells, placental microvascular endothelial cells were treated with mimic or siRNA of DAPK2 and mTOR to detect the expression of related genes, cell autophagy and apoptosis and oxidative damage. Finally, rats were modeled with HDCP to verify the cell experiment results. DAPK2 was downregulated in HDCP, and could activate mTOR. Besides, DAPK2 overexpression led to decreases in autophagy in HPVECs as well as apoptosis and oxidative damage in placental cells indicated by a substantial decrease in Beclin-1, LC3 II/LC3 I and Bax along with an increase in Bcl-2, 4EBP1 and p70S6K. It also ameliorates blood pressure elevation in HDCP rats. The study defined remission effect of DAPK2 on placental cell oxidative damage and apoptosis in HDCP via mTOR activation. Together, DAPK2 regulating mTOR pathway presents a promising therapy for HDCP treatment.

Beclin1 overexpression suppresses tumor cell proliferation and survival via an autophagy‑dependent pathway in human synovial sarcoma cells

Beclin1 is an important autophagy‑related prot-ein, which is involved in both autophagy and apoptosis. In recent years, the antitumor effect of Beclin1 has received increased attention. In the present study, we established a stable Beclin1‑overexpressing cell line with SW982 human synovial sarcoma cells. We found that Beclin1 overexpression decreased the cell viability, inhibited proliferation and induced apoptosis in SW982 cells. The expression levels of Bcl‑2 and PCNA were decreased, while the levels of cleaved‑caspase‑3 and cleaved‑PARP were increased. Beclin1 is closely related with autophagy, thus the autophagy‑related markers LC3 and p62 were detected by western blot analysis, and transmission electron microscopy was used to observe autophagosomes. The results showed that the expression level of LC3II was increased and that of p62 was decreased. Moreover, many double membrane‑enclosed autophagosomes were found in cells with Beclin1 overexpression, which indicated that the autophagic activity was enhanced. To explore the effect of autophagy on the viability of SW982 cells, Atg5 was knocked down using siRNA to inhibit the autophagic activity. We found that autophagy contributed to the decrease in cell viability. Knockdown of Atg5 increased the viability and decreased the apoptotic rate of SW982 cells with Beclin1 overexpression. The expression level of Bcl‑2 was increased, while the expression levels of cleaved‑caspase‑3 and cleaved‑PARP were decreased. We also found that the Akt/Bcl‑2/caspase‑9 pathway was involved. The phosphorylation of AKT was positively correlated with cell viability. The cleavage of caspase‑9 was increased by Beclin1 overexpression and decreased by inhibition of autophagy. Altogether, our results suggested that both autophagy and apoptosis contributed to the antitumor effect of Beclin1 in SW982 cells.