ERK signaling is required for VEGF-A/VEGFR2-induced differentiation of porcine adipose-derived mesenchymal stem cells into endothelial cells

An Overview of Cancer Biology, Pathophysiological Development and It's Treatment Modalities: Current Challenges of Cancer anti-Angiogenic Therapy

A number of conditions and factors can cause the transformation of normal cells in the body into malignant tissue by changing the normal functions of a wide range of regulatory, apoptotic, and signal transduction pathways. Despite the current deficiency in fully understanding the mechanism of cancer action accurately and clearly, numerous genes and proteins that are causally involved in the initiation, progression, and metastasis of cancer have been identified. But due to the lack of space and the abundance of details on this complex topic, we have emphasized here more recent advances in our understanding of the principles implied tumor cell transformation, development, invasion, angiogenesis, and metastasis. Inhibition of angiogenesis is a significant strategy for the treatment of various solid tumors, that essentially depend on cutting or at least limiting the supply of blood to micro-regions of tumors, leading to pan-hypoxia and pan-necrosis inside solid tumor tissues. Researchers have continued to enhance the efficiency of anti-angiogenic drugs over the past two decades, to identify their potential in the drug interaction, and to discover reasonable interpretations for possible resistance to treatment. In this review, we have discussed an overview of cancer history and recent methods use in cancer therapy, focusing on anti-angiogenic inhibitors targeting angiogenesis formation. Further, this review has explained the molecular mechanism of action of these anti-angiogenic inhibitors in various tumor types and their limitations use. In addition, we described the synergistic mechanisms of immunotherapy and anti-angiogenic therapy and summarizes current clinical trials of these combinations. Many phase III trials found that combining immunotherapy and anti-angiogenic therapy improved survival. Therefore, targeting the source supply of cancer cells to grow and spread with new anti-angiogenic agents in combination with different conventional therapy is a novel method to reduce cancer progression. The aim of this paper is to overview the varying concepts of cancer focusing on mechanisms involved in tumor angiogenesis and provide an overview of the recent trends in anti-angiogenic strategies for cancer therapy.

Treatment of cytokine release syndrome-induced vascular endothelial injury using mesenchymal stem cells

Cytokine release syndrome (CRS) is an acute systemic inflammatory reaction in which hyperactivated immune cells suddenly release a large amount of cytokines, leading to exaggerated inflammatory responses, multiple organ dysfunction, and even death. Although palliative treatment strategies have significantly reduced the overall mortality, novel targeted treatment regimens with superior therapy efficacy are urgently needed. Vascular endothelial cells (ECs) are important target cells of systemic inflammation, and their destruction is considered to be the initiating event underlying many serious complications of CRS. Mesenchymal stem/stromal cells (MSCs) are multipotent cells with self-renewing differentiation capacity and immunomodulatory properties. MSC transplantation can effectively suppress the activation of immune cells, reduce the bulk release of cytokines, and repair damaged tissues and organs. Here, we review the molecular mechanisms underlying CRS-induced vascular endothelial injury and discuss potential treatments using MSCs. Preclinical studies demonstrate that MSC therapy can effectively repair endothelium damage and thus reduce the incidence and severity of ensuing CRS-induced complications. This review highlights the therapeutic role of MSCs in fighting against CRS-induced EC damage, and summarizes the possible therapeutic formulations of MSCs for improved efficacy in future clinical trials.

African swine fever virus A137R protein inhibits NF-κB activation via suppression of MyD88 signaling in PK15 and 3D4/21 cells in vitro

African swine fever (ASF) is an infectious disease with high mortality caused by African swine fever virus (ASFV), which poses a great threat to the global swine industry. ASFV has evolved multiple strategies to evade host antiviral innate immunity by perturbing inflammatory responses and interferon production. However, the molecular mechanisms underlying manipulation of inflammatory responses by ASFV proteins are not fully understood. Here, we report that A137R protein of ASFV is a key suppressor of host inflammatory responses. Ectopic expression of ASFV A137R in HEK293T cells significantly inhibited the activation of IL-8 and NF-κB promoters triggered by Sendai virus (SeV), influenza A virus (IAV), or vesicular stomatitis virus (VSV). Accordingly, forced A137R expression caused a significant decrease in the production of several inflammatory cytokines such as IL-8, IL-6 and TNF-α in the cells infected with SeV or IAV. Similar results were obtained from experiments using A137R overexpressing PK15 and 3D4/21 cells infected with SeV or VSV. Furthermore, we observed that A137R impaired the activation of MAPK and NF-κB signaling pathways, as enhanced expression of A137R significantly decreased the phosphorylation of JNK, p38 and p65 respectively upon viral infection (SeV or IAV) and IL-1β treatment. Mechanistically, we found that A137R interacted with MyD88, and dampened MyD88-mediated activation of MAPK and NF-κB signaling. Together, these findings uncover a critical role of A137R in restraining host inflammatory responses, and improve our understanding of complicated mechanisms whereby ASFV evades innate immunity.

Adipose-Derived Stem Cells: Angiogenetic Potential and Utility in Tissue Engineering

Adipose tissue (AT) is a large and important energy storage organ as well as an endocrine organ with a critical role in many processes. Additionally, AT is an enormous and easily accessible source of multipotent cell types used in our day for all types of tissue regeneration. The ability of adipose-derived stem cells (ADSCs) to differentiate into other types of cells, such as endothelial cells (ECs), vascular smooth muscle cells, or cardiomyocytes, is used in tissue engineering in order to promote/stimulate the process of angiogenesis. Being a key for future successful clinical applications, functional vascular networks in engineered tissue are targeted by numerous in vivo and ex vivo studies. The article reviews the angiogenic potential of ADSCs and explores their capacity in the field of tissue engineering (TE).

Bee Venom Stimulates Growth Factor Release from Adipose-Derived Stem Cells to Promote Hair Growth

Limited evidence suggests that stimulating adipose-derived stem cells (ASCs) indirectly promotes hair growth. We examined whether bee venom (BV) activated ASCs and whether BV-induced hair growth was facilitated by enhanced growth factor release by ASCs. The induction of the telogen-to-anagen phase was studied in mice. The underlying mechanism was investigated using organ cultures of mouse vibrissa hair follicles. When BV-treated ASCs were injected subcutaneously into mice, the telogen-to-anagen transition was accelerated and, by day 14, the hair weight increased. Quantitative polymerase chain reaction (qPCR) revealed that BV influenced the expression of several molecules, including growth factors, chemokines, channels, transcription factors, and enzymes. Western blot analysis was employed to verify the protein expression levels of extracellular-signal-regulated kinase (ERK) and phospho-ERK. Both the Boyden chamber experiment and scratch assay confirmed the upregulation of cell migration by BV. Additionally, ASCs secreted higher levels of growth factors after exposure to BV. Following BV therapy, the gene expression levels of alkaline phosphatase (ALP), fibroblast growth factor (FGF)-1 and 6, endothelial cell growth factor, and platelet-derived growth factor (PDGF)-C were upregulated. The findings of this study suggest that bee venom can potentially be utilized as an ASC-preconditioning agent for hair regeneration.

Dendronized chitosan hydrogel with GIT1 to accelerate bone defect repair through increasing local neovascular amount

Bone defects have long been a major healthcare issue because of the difficulties in regenerating bone mass volume and the high cost of treatment. G protein-coupled receptor kinase 2 interacting protein 1 (GIT1) has been proven to play an important role both in vascular development and in bone fracture healing. In this study, a type of thermoresponsive injectable hydrogel from oligoethylene glycol-based dendronized chitosan (G1-CS) was loaded with GIT1-plasmids (G1-CS/GIT1), and used to fill unicortical bone defects. RT-PCR analysis confirmed that G1-CS/GIT1 enhanced DNA transfection in MSCs both in vitro and in vivo. From the results of micro-CT, RT-PCR and histological analysis, it can be concluded that G1-CS/GIT1 accelerated the bone healing rate and increased the amount of neovascularization around the bone defects. In addition, an adeno-associated virus (AAV)-GIT1 was constructed to transfect mesenchymal stem cells. The results of capillary tube formation assay, immunofluorescence staining and western blot analysis proved that high expression of GIT1 induces mesenchymal stem cells to differentiate into endothelial cells. RT-PCR analysis and capillary tube formation assay confirmed that the Notch signaling pathway was activated in the differentiation process. Overall, we developed an efficient strategy through combination of injectable hydrogel and G1T1 for bone tissue engineering.

Adipose-Derived Stem Cells to Treat Ischemic Diseases: The Case of Peripheral Artery Disease

Critical limb ischemia incidence and prevalence have increased over the years. However, there are no successful treatments to improve quality of life and to reduce the risk of cardiovascular and limb events in these patients. Advanced regenerative therapies have focused their interest on the generation of new blood vessels to repair tissue damage through the use of stem cells. One of the most promising sources of stem cells with high potential in cell-based therapy is adipose-derived stem cells (ASCs). ASCs are adult mesenchymal stem cells that are relatively abundant and ubiquitous and are characterized by a multilineage capacity and low immunogenicity. The proangiogenic benefits of ASCs may be ascribed to: (a) paracrine secretion of proangiogenic molecules that may stimulate angiogenesis; (b) secretion of microvesicles/exosomes that are also considered as a novel therapeutic prospect for treating ischemic diseases; and (c) their differentiation capability toward endothelial cells (ECs). Although we know the proangiogenic effects of ASCs, the therapeutic efficacy of ASCs after transplantation in peripheral artery diseases patients is still relatively low. In this review, we evidence the potential therapeutic use of ASCs in ischemic regenerative medicine. We also highlight the main challenges in the differentiation of these cells into functional ECs. However, significant efforts are still needed to ascertain relevant transcription factors, intracellular signaling and interlinking pathways in endothelial differentiation.

Extracellular matrix cues regulate the differentiation of pluripotent stem cell-derived endothelial cells

The generation of endothelial cells (ECs) from human pluripotent stem cells (PSCs) has been a promising approach for treating cardiovascular diseases for several years. Human PSCs, particularly induced pluripotent stem cells (iPSCs), are an attractive source of ECs for cell therapy. Although there is a diversity of methods for endothelial cell differentiation using biochemical factors, such as small molecules and cytokines, the efficiency of EC production varies depending on the type and dose of biochemical factors. Moreover, the protocols in which most EC differentiation studies have been performed were in very unphysiological conditions that do not reflect the microenvironment of native tissue. The microenvironment surrounding stem cells exerts variable biochemical and biomechanical stimuli that can affect stem cell differentiation and behavior. The stiffness and components of the extracellular microenvironment are critical inducers of stem cell behavior and fate specification by sensing the extracellular matrix (ECM) cues, adjusting the cytoskeleton tension, and delivering external signals to the nucleus. Differentiation of stem cells into ECs using a cocktail of biochemical factors has been performed for decades. However, the effects of mechanical stimuli on endothelial cell differentiation remain poorly understood. This review provides an overview of the methods used to differentiate ECs from stem cells by chemical and mechanical stimuli. We also propose the possibility of a novel EC differentiation strategy using a synthetic and natural extracellular matrix.

Prognosis and Personalized Treatment Prediction in Different Mutation-Signature Hepatocellular Carcinoma

Introduction

Mutation patterns have been extensively explored to decipher the etiologies of hepatocellular carcinoma (HCC). However, the study and potential clinical role of mutation patterns to stratify high-risk patients and optimize precision therapeutic strategies remain elusive in HCC.

Methods

Using exon-sequencing data in public (n=362) and in-house (n=30) cohorts, mutation signatures were extracted to decipher relationships with the etiology and prognosis in HCC. The proteomics (n=159) and cell-line transcriptome data (n=1019) were collected to screen the implication of sensitive drugs. A novel multi-step machine-learning framework was then performed to construct a classification predictor, including recognizing stable reversed gene pairs, establishing a robust prediction model, and validating the robustness of the predictor in five independent cohorts (n=900).

Results

Two heterogeneous mutation signature clusters were identified, and a high-risk prognosis cluster was recognized for further analysis. Notably, mutation signature cluster 1 (MSC1) was featured by activated anti-tumor immune and metabolism dysfunctional states, higher genomic instability (high TMB, SNV neoantigen, indel neoantigens, and total neoantigens), and a dismal prognosis. Notably, MSC performed as an independent risk factor than clinical traits (eg, stage, vascular invasion). Additionally, afatinib and canertinib were recognized which might have potential therapeutic implications in MSC1, and the targets of these drugs presented a higher expression in both gene and protein levels in HCC.

Discussion

Our studies may provide a promising platform for improving prognosis and tailoring therapy in HCC.

Molecular Mechanisms Responsible for Mesenchymal Stem Cell-Based Modulation of Obstructive Sleep Apnea

Mesenchymal stem cells (MSCs) are adult stem cells that reside in almost all postnatal tissues where, due to the potent regenerative, pro-angiogenic and immunomodulatory properties, regulate tissue homeostasis. Obstructive sleep apnea (OSA) induces oxidative stress, inflammation and ischemia which recruit MSCs from their niches in inflamed and injured tissues. Through the activity of MSC-sourced anti-inflammatory and pro-angiogenic factors, MSCs reduce hypoxia, suppress inflammation, prevent fibrosis and enhance regeneration of damaged cells in OSA-injured tissues. The results obtained in large number of animal studies demonstrated therapeutic efficacy of MSCs in the attenuation of OSA-induced tissue injury and inflammation. Herewith, in this review article, we emphasized molecular mechanisms which are involved in MSC-based neo-vascularization and immunoregulation and we summarized current knowledge about MSC-dependent modulation of OSA-related pathologies.

Low-Level Laser Therapy Induces Melanoma Tumor Growth by Promoting Angiogenesis

The effects of low-level laser therapy (LLLT) on tumor growth are inconsistent. In this study, we investigated the effects of LLLT on melanoma tumor growth and angiogenesis. C57/BL6 mice were challenged with B16F10 melanoma cells and treated with LLLT for 5 consecutive days; untreated mice were used as controls. Tumor weight, angiogenesis, immunohistochemistry, and protein levels were compared between the treated and untreated mice. In an in vitro experiment, B16F10 cells were treated with LLLT. Proteins were extracted and subjected to Western blot analysis for analyzing signaling pathways. Compared with the findings in the untreated mice, tumor weight substantially increased in the treated mice. Both immunohistochemical and Western blot analyses revealed markedly increased levels of CD31, a biomarker of vascular differentiation, in the LLLT group. In B16F10 cells, LLLT considerably induced the phosphorylation of extracellular signal-regulated kinase (ERK), which, in turn, phosphorylated p38 mitogen-activated protein kinase (MAPK). Furthermore, LLLT induced the expression of vascular endothelial growth factor, but not hypoxia-inducible factor-1α, through the ERK/p38 MAKP signaling pathways. Our findings indicate that LLLT induces melanoma tumor growth by promoting angiogenesis. Therefore, it should be avoided in patients with melanoma.

FNDC5 Promotes Adipogenic Differentiation of Primary Preadipocytes in Mashen Pigs

Fibronectin type III domain-containing protein 5 (FNDC5) plays an important role in fat deposition, which can be cut to form Irisin to promote fat thermogenesis, resulting in a decrease in fat content. However, the mechanism of FNDC5 related to fat deposition in pigs is still unclear. In this research, we studied the expression of FNDC5 on different adiposes and its function in the adipogenic differentiation of primary preadipocytes in Mashen pigs. The expression pattern of FNDC5 was detected by qRT-PCR and Western blotting in Mashen pigs. FNDC5 overexpression and interference vectors were constructed and transfected into porcine primary preadipocytes by lentivirus. Then, the expression of key adipogenic genes was detected by qRT-PCR and the content of lipid droplets was detected by Oil Red O staining. The results showed that the expression of FNDC5 in abdominal fat was higher than that in back subcutaneous fat in Mashen pigs, whereas the expression in back subcutaneous fat of Mashen pigs was significantly higher than that of Large White pigs. In vitro, FNDC5 promoted the adipogenic differentiation of primary preadipocytes of Mashen pigs and upregulated the expression of genes related to adipogenesis, but did not activate the extracellular signal-regulated kinase (ERK) signaling pathway. This study can provide a theoretical basis for FNDC5 in adipogenic differentiation in pigs.

Yeast beta-glucan mediates histone deacetylase 5-induced angiogenesis in vascular endothelial cells

The role of yeast-derived β-glucan in angiogenesis has not been elucidated because there have been few specific studies on its clinical and physiological significance. Therefore, this study investigated the correlation between β-glucan and histone deacetylase 5 (HDAC5) in human umbilical vein endothelial cells (HUVECs), revealing the role of β-glucan in angiogenesis. We confirmed that HDAC5 was phosphorylated by β-glucan stimulation and released from the nucleus to the cytoplasm. Furthermore, we found that β-glucan-stimulated HDAC5 translocation mediates the transcriptional activation of MEF2. As a result, the expression of KLF2, EGR2, and NR4A2, whose expression is MEF2-dependent and involved in angiogenesis, increased. Thus, we showed the activity of β-glucan in angiogenesis through in vitro and ex vivo assays including cell migration, tube formation, and aortic ring analyses. Specifically, application of an HDAC5 inhibitor repressed MEF2 transcriptional activation in both in vitro and ex vivo angiogenesis. HDAC5 inhibitor LMK235 inhibited the proangiogenic activity of beta-glucan, suggesting that β-glucan induces angiogenesis through HDAC5. These findings suggest that HDAC5 is essential for angiogenesis, and that β-glucan induces angiogenesis. In conclusion, this study demonstrates that β-glucan induces angiogenesis through HDAC5. It also suggests that β-glucan has potential value as a novel therapeutic agent for modulating angiogenesis.

Bladder Cancer Cells Exert Pleiotropic Effects on Human Adipose-Derived Stem Cells

Stem cell-based therapies are considered one of the most promising disciplines in biomedicine. Bladder cancer patients could benefit from therapies directed to promote healing after invasive surgeries or to lessen urinary incontinence, a common side effect of both cancer itself and the treatment. However, the local delivery of cells producing large amounts of paracrine factors may alter interactions within the microenvironment. For this reason, reconstructive cellular therapies for patients with a history of cancer carry a potential risk of tumor reactivation. We used an indirect co-culture model to characterize the interplay between adipose-derived stem cells and bladder cancer cells. Incubation with ASCs increased MCP-1 secretion by bladder cancer cells (from 2.1-fold to 8.1-fold, depending on the cell line). Cancer cell-derived factors altered ASC morphology. Cells with atypical shapes and significantly enlarged volumes appeared within the monolayer. Incubation in a conditioned medium (CM) containing soluble mediators secreted by 5637 and HB-CLS-1 bladder cancer cell lines decreased ASC numbers by 47.5% and 45.7%. A significant increase in adhesion to ECM components, accompanied by reduced motility and sheet migration, was also observed after incubation in CM from 5637 and HB-CLS-1 cells. No differences were observed when ASCs were co-cultured with HT-1376 cells. Our previous and present results indicate that soluble mediators secreted by ASCs and bladder cancer cells induce opposite effects influencing cells that represent the non-muscle-invasive urinary bladder.

Chemical Distance Measurement and System Pharmacology Approach Uncover the Novel Protective Effects of Biotransformed Ginsenoside C-Mc against UVB-Irradiated Photoaging

Long-term exposure to ultraviolet light induces photoaging and may eventually increase the risk of skin carcinogenesis. Rare minor ginsenosides isolating from traditional medicine Panax (ginseng) have shown biomedical efficacy as antioxidation and antiphotodamage agents. However, due to the difficulty of component extraction and wide variety of ginsenoside, the identification of active antiphotoaging ginsenoside remains a huge challenge. In this study, we proposed a novel in silico approach to identify potential compound against photoaging from 82 ginsenosides. Specifically, we calculated the shortest distance between unknown and known antiphotoaging ginsenoside set in the chemical space and applied chemical structure similarity assessment, drug-likeness screening, and ADMET evaluation for the candidates. We highlighted three rare minor ginsenosides (C-Mc, Mx, and F2) that possess high potential as antiphotoaging agents. Among them, C-Mc deriving from American ginseng (Panax quinquefolius L.) was validated by wet-lab experimental assays and showed significant antioxidant and cytoprotective activity against UVB-induced photodamage in human dermal fibroblasts. Furthermore, system pharmacology analysis was conducted to explore the therapeutic targets and molecular mechanisms through integrating global drug-target network, high quality photoaging-related gene profile from multiomics data, and skin tissue-specific expression protein network. In combination with in vitro assays, we found that C-Mc suppressed MMP production through regulating the MAPK/AP-1/NF-κB pathway and expedited collagen synthesis via the TGF-β/Smad pathway, as well as enhanced the expression of Nrf2/ARE to hold a balance of endogenous oxidation. Overall, this study offers an effective drug discovery framework combining in silico prediction and in vitro validation, uncovering that ginsenoside C-Mc has potential antiphotoaging properties and might be a novel natural agent for use in oral drug, skincare products, or functional food.

TLR9 agonist suppresses choroidal neovascularization by restricting endothelial cell motility via ERK/c-Jun pathway

INTRODUCTION

Choroidal neovascularization (CNV) is the feature of neovascular age-related macular degeneration (AMD). It has been demonstrated that inflammation plays a key role in the development of CNV. Here we aim to investigate how TLR9 agonist (CpG-ODN), one of the key regulators of inflammatory responses, suppresses CNV in vivo.

MATERIALS AND METHODS

The cell viability was assessed by MTT and EdU test after CpG-ODN treatment. Endothelial cells gap assay, tube formation assay and transwell assay were practiced to observe how CpG-ODN affected the endothelial cells functions. The choroidal explants and laser-induced CNV model were built to investigate how CpG-ODN suppressed angiogenesis. The ERK and c-Jun expression were evaluated to assess if CpG-ODN affected cell proliferation. Flow cytometry and qPCR was practiced to observe how CpG-ODN regulated cell proliferation.

RESULTS

Our data showed that CpG-ODN not only reduced CNV area in vivo, but also decreased the RPE damage. CpG-ODN inhibited endothelial cells from migration and forming tubes, while the effect was not toxic. EdU test and MTT test suggested that CpG-ODN inhibited endothelial cells proliferation. CpG-ODN significantly increased protein expression of phosphorylated c-Jun but reduced phosphorylated ERK in HUVECs, which was confirmed in ERK transfected 293T cells. JNK inhibitor abolished the suppression of endothelial cells migration and tube formation by CpG-ODN. The findings were also in agreement with the observation in CpG-ODN treated CNV eyes in vivo. The flow cytometry and qPCR data revealed that the suppression of cell motility by CpG-ODN was achieved by arresting endothelial cells cell cycle at G0/G1 phase.

CONCLUSIONS

Our study demonstrated that CpG-ODN suppressed endothelial cell motility by restricting the cell cycle progression at G0/G1 phase, the effect of which was achieved by interacting with ERK/c-Jun pathways.

Mechanoregulation of Vascular Endothelial Growth Factor Receptor 2 in Angiogenesis

The endothelial cells that compose the vascular system in the body display a wide range of mechanotransductive behaviors and responses to biomechanical stimuli, which act in concert to control overall blood vessel structure and function. Such mechanosensitive activities allow blood vessels to constrict, dilate, grow, or remodel as needed during development as well as normal physiological functions, and the same processes can be dysregulated in various disease states. Mechanotransduction represents cellular responses to mechanical forces, translating such factors into chemical or electrical signals which alter the activation of various cell signaling pathways. Understanding how biomechanical forces drive vascular growth in healthy and diseased tissues could create new therapeutic strategies that would either enhance or halt these processes to assist with treatments of different diseases. In the cardiovascular system, new blood vessel formation from preexisting vasculature, in a process known as angiogenesis, is driven by vascular endothelial growth factor (VEGF) binding to VEGF receptor 2 (VEGFR-2) which promotes blood vessel development. However, physical forces such as shear stress, matrix stiffness, and interstitial flow are also major drivers and effectors of angiogenesis, and new research suggests that mechanical forces may regulate VEGFR-2 phosphorylation. In fact, VEGFR-2 activation has been linked to known mechanobiological agents including ERK/MAPK, c-Src, Rho/ROCK, and YAP/TAZ. In vascular disease states, endothelial cells can be subjected to altered mechanical stimuli which affect the pathways that control angiogenesis. Both normalizing and arresting angiogenesis associated with tumor growth have been strategies for anti-cancer treatments. In the field of regenerative medicine, harnessing biomechanical regulation of angiogenesis could enhance vascularization strategies for treating a variety of cardiovascular diseases, including ischemia or permit development of novel tissue engineering scaffolds. This review will focus on the impact of VEGFR-2 mechanosignaling in endothelial cells (ECs) and its interaction with other mechanotransductive pathways, as well as presenting a discussion on the relationship between VEGFR-2 activation and biomechanical forces in the extracellular matrix (ECM) that can help treat diseases with dysfunctional vascular growth.

Mesenchymal stem cell therapy attenuates complement C3 deposition and improves the delicate equilibrium between angiogenic and anti-angiogenic factors in abortion-prone mice

Immunological disorders are one of the main causes of recurrent spontaneous abortions (RSA). A rapidly expanding body of evidence indicates that excessive activation of the complement system is critically involved in the development of miscarriages. In the CBA/J × DBA/2 murine model of recurrent miscarriage, exaggerated and unrestrained complement activation is reported to be the underlying cause of angiogenic factor imbalance and persistent inflammation. We have previously shown that mesenchymal stem cell (MSC) therapy can significantly reduce the abortion rate in abortion-prone mice through regulating the feto-maternal immune response. In the present study, we hypothesized that MSCs might improve the balance of angiogenic factors at the feto-maternal unit of CBA/J × DBA/2 mice by restraining complement activation and deposition. To explore this hypothesis, autologous adipose tissue-derived mesenchymal stem cells (AD-MSCs) were administered intra-peritoneally to abortion-prone mice on the 4.5th day of gestation. Control mice received PBS as vehicle. On day 13.5 of pregnancy, deposition of the complement component C3 and expression levels of Crry, CFD (adipsin), VEGF, PlGF and FLT-1 were measured at the feto-maternal interface by immunohistochemistry and real-time PCR, respectively. Decidual cells were also cultured in RPMI 1640 medium for 48 h and VEGF and sFLT-1 protein levels were quantified in supernatants using enzyme-linked immunosorbent assay (ELISA). Our results indicated that MSC therapy significantly reduced C3 deposition and adipsin transcription in the fetal-maternal interface of abortion-prone mice. Furthermore, administration of MSCs robustly upregulated the mRNA expression levels of Crry, VEGF, PlGF and FLT-1 in the placenta and decidua of CBA/J × DBA/2 mice. Consistently, the in vitro results demonstrated that decidual cells obtained from MSC-treated dams produced increased concentrations of VEGF in culture supernatants, with concomitant decreased levels of sFLT-1 protein. Here, we show for the first time that adoptive transfer of MSCs rectifies the disturbed balance of angiogenic factors observed at the feto-maternal unit of CBA/J × DBA/2 mice, in part at least, through inhibiting excessive complement activation and promoting the production of angiogenic factors. Collectively, these alterations seem to play a pivotal role in reducing the abortion rate and improving the intrauterine condition for the benefit of the fetus.

Adipose mesenchymal stem cells and gingival mesenchymal stem cells have a comparable effect in endothelium repair

Restenosis is the major factor influencing the long-term success rate of angioplasty and stent implantation and effective strategies to prevent restenosis remain limited. Mesenchymal stem cells (MSCs) are pluripotent stem cells capable of self-renewal and multidirectional differentiation, which may be able to promote endothelium repair, thereby reducing restenosis. The present study aimed to evaluate the effects of adipose MSCs (AMSCs) and gingival MSCs (GMSCs) on endothelium repair. MSCs were isolated from two human tissue types, namely adipose tissue and gingival tissue, and the effects of AMSCs and GMSCs in ex vivo endothelium repair and on vascular smooth muscle cell (SMC) growth were examined. To compare the feasibility of using AMSCs and GMSCs for the repair of endothelium damage in endothelial cell (EC) damage and vasoproliferative disorders, an ex vivo model of endothelium repair in a co-culture system was developed. It was indicated that AMSCs and GMSCs expressed characteristic MSC markers (CD105 and CD166). 3H-thymidine incorporation in the co-culture group of AMSCs and SMCs in the presence of ECs was lower compared with that in the GMSC and SMC co-culture group. The protein expression level of proliferating cell nuclear antigen in the co-culture group of AMSCs and SMCs in the presence of ECs were lower compared with that in the GMSC and SMC co-culture group. After co-culture with ECs for 5 days, 25.71±3.08% of AMSCs began to express CD31 protein and 20.06±2.09% of GMSCs began to express CD31 protein. Furthermore, anti-VEGF antibody was able to inhibit MSC differentiation. Collectively, the present results suggested that seeding of AMSCs had a stronger effect to inhibit the proliferation and migration of SMCs compared with GMSCs.

Angiogenic Effects and Crosstalk of Adipose-Derived Mesenchymal Stem/Stromal Cells and Their Extracellular Vesicles with Endothelial Cells

Adipose-derived mesenchymal stem/stromal cells (ASCs) are an adult stem cell population able to self-renew and differentiate into numerous cell lineages. ASCs provide a promising future for therapeutic angiogenesis due to their ability to promote blood vessel formation. Specifically, their ability to differentiate into endothelial cells (ECs) and pericyte-like cells and to secrete angiogenesis-promoting growth factors and extracellular vesicles (EVs) makes them an ideal option in cell therapy and in regenerative medicine in conditions including tissue ischemia. In recent angiogenesis research, ASCs have often been co-cultured with an endothelial cell (EC) type in order to form mature vessel-like networks in specific culture conditions. In this review, we introduce co-culture systems and co-transplantation studies between ASCs and ECs. In co-cultures, the cells communicate via direct cell-cell contact or via paracrine signaling. Most often, ASCs are found in the perivascular niche lining the vessels, where they stabilize the vascular structures and express common pericyte surface proteins. In co-cultures, ASCs modulate endothelial cells and induce angiogenesis by promoting tube formation, partly via secretion of EVs. In vivo co-transplantation of ASCs and ECs showed improved formation of functional vessels over a single cell type transplantation. Adipose tissue as a cell source for both mesenchymal stem cells and ECs for co-transplantation serves as a prominent option for therapeutic angiogenesis and blood perfusion in vivo.

Microglia modulation with 1070-nm light attenuates Aβ burden and cognitive impairment in Alzheimer's disease mouse model

Photobiomodulation, by utilizing low-power light in the visible and near-infrared spectra to trigger biological responses in cells and tissues, has been considered as a possible therapeutic strategy for Alzheimer's disease (AD), while its specific mechanisms have remained elusive. Here, we demonstrate that cognitive and memory impairment in an AD mouse model can be ameliorated by 1070-nm light via reducing cerebral β-amyloid (Aβ) burden, the hallmark of AD. The glial cells, including microglia and astrocytes, play important roles in Aβ clearance. Our results show that 1070-nm light pulsed at 10 Hz triggers microglia rather than astrocyte responses in AD mice. The 1070-nm light-induced microglia responses with alteration in morphology and increased colocalization with Aβ are sufficient to reduce Aβ load in AD mice. Moreover, 1070-nm light pulsed at 10 Hz can reduce perivascular microglia and promote angiogenesis to further enhance Aβ clearance. Our study confirms the important roles of microglia and cerebral vessels in the use of 1070-nm light for the treatment of AD mice and provides a framework for developing a novel therapeutic approach for AD.

CD146 controls the quality of clinical grade mesenchymal stem cells from human dental pulp

Background

Human mesenchymal stem cells from dental pulp (hMSC-DP), including dental pulp stem cells from permanent teeth and exfoliated deciduous teeth, possess unique MSC characteristics such as expression of specific surface molecules and a high proliferation rate. Since hMSC-DP have been applied in numerous clinical studies, it is necessary to establish criteria to evaluate their potency for cell-based therapies.

Methods

We compared stem cell properties of hMSC-DP at passages 5, 10 and 20 under serum (SE) and serum-free (SF) culture conditions. Cell morphology, proliferation capacity, chromosomal stability, surface phenotypic profiles, differentiation and immunoregulation ability were evaluated. In addition, we assessed surface molecule that regulates hMSC-DP proliferation and immunomodulation.

Results

hMSC-DP exhibited a decrease in proliferation rate and differentiation potential, as well as a reduced expression of CD146 when cultured under continuous passage conditions. SF culture conditions failed to alter surface marker expression, chromosome stability or proliferation rate when compared to SE culture. SF-cultured hMSC-DP were able to differentiate into osteogenic, adipogenic and neural cells, and displayed the capacity to regulate immune responses. Notably, the expression level of CD146 showed a positive correlation with proliferation, differentiation, and immunomodulation, suggesting that CD146 can serve as a surface molecule to evaluate the potency of hMSC-DP. Mechanistically, we found that CD146 regulates proliferation and immunomodulation of hMSC-DP through the ERK/p-ERK pathway.

Conclusion

This study indicates that SF-cultured hMSC-DP are appropriate for producing clinical-grade cells. CD146 is a functional surface molecule to assess the potency of hMSC-DP.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02559-4.

Coatings in Decellularized Vascular Scaffolds for the Establishment of a Functional Endothelium: A Scoping Review of Vascular Graft Refinement

Developments in tissue engineering techniques have allowed for the creation of biocompatible, non-immunogenic alternative vascular grafts through the decellularization of existing tissues. With an ever-growing number of patients requiring life-saving vascular bypass grafting surgeries, the production of functional small diameter decellularized vascular scaffolds has never been more important. However, current implementations of small diameter decellularized vascular grafts face numerous clinical challenges attributed to premature graft failure as a consequence of common failure mechanisms such as acute thrombogenesis and intimal hyperplasia resulting from insufficient endothelial coverage on the graft lumen. This review summarizes some of the surface modifying coating agents currently used to improve the re-endothelialization efficiency and endothelial cell persistence in decellularized vascular scaffolds that could be applied in producing a better patency small diameter vascular graft. A comprehensive search yielding 192 publications was conducted in the PubMed, Scopus, Web of Science, and Ovid electronic databases. Careful screening and removal of unrelated publications and duplicate entries resulted in a total of 16 publications, which were discussed in this review. Selected publications demonstrate that the utilization of surface coating agents can induce endothelial cell adhesion, migration, and proliferation therefore leads to increased re-endothelialization efficiency. Unfortunately, the large variance in methodologies complicates comparison of coating effects between studies. Thus far, coating decellularized tissue gave encouraging results. These developments in re-endothelialization could be incorporated in the fabrication of functional, off-the-shelf alternative small diameter vascular scaffolds.

Photobiomodulation Therapy to Promote Angiogenesis in Diabetic Mice with Hindlimb Ischemia

Objective: To assess whether photobiomodulation therapy (PBMT) induces angiogenesis in diabetic mice with hindlimb ischemia (HLI). Background: Patients with diabetes mellitus (DM) are at high risk of developing peripheral arterial disease (PAD) in the lower extremities. PBMT has been shown to promote angiogenesis both in vitro and in vivo and could be a treatment for DM patients with PAD. Methods: Femoral artery ligation/excision in mice was performed to induce HLI as an animal model of PAD. PBMT at a dose of 660 nm and 1.91 J/cm² was delivered for 10 min on 5 consecutive days after the HLI surgery. Control mice received HLI only. Mice in the DM group were injected with streptozocin to induce diabetes before HLI surgery. Mice in the laser and DM+ laser groups received both HLI and PBMT, and the latter group had induced DM. After the laser treatment, lower limb blood flow was evaluated by laser Doppler. The capillary density and CD31 were analyzed by immunofluorescence staining, and protein levels of vascular endothelial growth factor (VEGF)-A, hypoxia-inducible factor-1α (HIF-1α), inducible nitric oxide synthase (iNOS), endothelial nitric oxide synthase (eNOS), and extracellular signal-regulated kinases (ERK) were measured by Western blotting of tissue samples. Results: Compared with the control and DM mice, the laser and DM+ laser groups had more than double the capillary density and blood perfusion rate. Levels of CD31 and VEGF-A proteins in groups that received laser were increased by 1.9- to 3.2-fold compared with groups that did not undergo laser treatment. Animals treated with PBMT exhibited significantly increased HIF-1α expression and ERK phosphorylation compared with animals that did not receive this treatment, and the amount of phospho-eNOS and iNOS increased and decreased, respectively. Conclusions: PBMT can induce therapeutic angiogenesis, indicating that low intensity laser could be a novel treatment for PAD patients.

Sustained oxidative stress instigates differentiation of cancer stem cells into tumor endothelial cells: Pentose phosphate pathway, reactive oxygen species and autophagy crosstalk

Tumor angiogenesis plays a vital role in tumor growth and metastasis. It is proven that in tumor vasculature, endothelial cells (ECs) originate from a small population of cancer cells introduced as cancer stem cells (CSCs). Autophagy has a vital role in ECs differentiation from CSCs and tumor angiogenesis. High levels of reactive oxygen species (ROS) increased autophagy by inhibition of glucose-6-phosphate dehydrogenase (G6PD) and inactivation of the pentose phosphate pathway (PPP). Previously, we suggested that cancer cells initially increase the glycolysis rate when encountering ROS, then the metabolic balance is changed from glycolysis to PPP, following the continuation of oxidative stress. In this study, we investigate the possible role of persistent oxidative stress in the differentiation of CSCs into tumor ECs by relying on the relationship between the ROS, PPP and autophagy. Because tumor angiogenesis plays an important role in the growth and development of cancer, understanding the mechanisms involved in differentiating ECs from CSCs can help find promising treatments for cancer.

Stem cell-based therapies for cardiac diseases: The critical role of angiogenic exosomes

Finding effective treatments for cardiac diseases is among the hottest subjects in medicine; cell-based therapies have brought great promises for managing a broad range of life-threatening heart complications such as myocardial infarction. After clarifying the critical role of angiogenesis in tissue repair and regeneration, various stem/progenitor cell were utilized to accelerate the healing of injured cardiac tissue. Embryonic, fetal, adult, and induced pluripotent stem cells have shown the appropriate proangiogenic potential for tissue repair strategies. The capability of stem cells for differentiating into endothelial lineages was initially introduced as the primary mechanism involved in improving angiogenesis and accelerated heart tissue repair. However, recent studies have demonstrated the leading role of paracrine factors secreted by stem cells in advancing neo-vessel formation. Genetically modified stem cells are also being applied for promoting angiogenesis regarding their ability to considerably overexpress and secrete angiogenic bioactive molecules. Yet, conducting further research seems necessary to precisely identify molecular mechanisms behind the proangiogenic potential of stem cells, including the signaling pathways and regulatory molecules such as microRNAs. In conclusion, stem cells' pivotal roles in promoting angiogenesis and consequent improved cardiac healing and remodeling processes should not be ignored, especially in the case of stem cell-derived extracellular vesicles.

VE-cadherin-based matrix promoting the self-reconstruction of pro-vascularization microenvironments and endothelial differentiation of human mesenchymal stem cells

Regulating the secretion and endothelial differentiation of human mesenchymal stem cells (hMSCs) plays an important role in the vascularization in tissue engineering and regenerative medicine. In this study, a recombinant cadherin fusion protein consisting of a human vascular endothelial-cadherin extracellular domain and immunoglobulin IgG Fc region (hVE-cad-Fc) was developed as a bioartificial matrix for modulating hMSCs. The hVE-cad-Fc matrix significantly enhanced the secretion of angiogenic factors, activated the VE-cadherin-VEGFR2/FAK-AKT/PI3K signaling pathway in hMSCs, and promoted the endothelial differentiation of hMSCs even without extra VEGF. Furthermore, the hVE-cad-Fc matrix was applied for the surface modification of a poly (lactic-co-glycolic acid) (PLGA) porous scaffold, which significantly improved the hemocompatibility and vascularization of the PLGA scaffold in vivo. These results revealed that the hVE-cad-Fc matrix should be a superior bioartificial ECM for remodeling the pro-vascularization extracellular microenvironment by regulating the secretion of hMSCs, and showed great potential for the vascularization in tissue engineering.

Global transcriptomic analysis reveals Lnc-ADAMTS9 exerting an essential role in myogenesis through modulating the ERK signaling pathway

Background

Long non-coding RNAs (lncRNAs) are emerging key regulators involved in a variety of biological processes such as cell differentiation and development. The balance between myogenesis and adipogenesis is crucial for skeletal muscle homeostasis in humans and meat quality in farm animals. The present study aimed to reveal the global transcriptomic profiles of adipogenic (Adi-) and myogenic (Myo-) precursors derived from porcine skeletal muscle and identify lncRNAs involved in the modulation of myogenesis homeostasis in porcine skeletal muscle.

Results

In this study, a total of 655 novel individual lncRNAs including differentially expressed 24 lncRNAs, and 755 differentially expressed mRNAs were identified (fold change ≥2 or ≤ 0.5 and adjusted P < 0.05). Integrated results of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis accompanied by the variation of intracellular Ca²⁺ concentration highlighted Lnc-ADAMTS9 involved in the modulation of myogenesis homeostasis in porcine skeletal muscle. Although Lnc-ADAMTS9 knock-down did not alter the mRNA expression of ADAMTS9, we demonstrated that Lnc-ADAMTS9 can promote myogenic proliferation and myogenic differentiation of myogenic precursors through inhibiting the ERK/MAPK signaling pathway.

Conclusion

We deciphered a comprehensive catalog of mRNAs and lncRNAs that might be involved in the regulation of myogenesis and adipogenesis homeostasis in the skeletal muscle of pigs. The Lnc-ADAMTS9 exerts an essential role in myogenesis through the ERK signaling pathway.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40104-020-00524-4.

Neovascularization: The Main Mechanism of MSCs in Ischemic Heart Disease Therapy

Mesenchymal stem cell (MSC) transplantation after myocardial infarction (MI) has been shown to effectively limit the infarct area in numerous clinical and preclinical studies. However, the primary mechanism associated with this activity in MSC transplantation therapy remains unclear. Blood supply is fundamental for the survival of myocardial tissue, and the formation of an efficient vascular network is a prerequisite for blood flow. The paracrine function of MSCs, which is throughout the neovascularization process, including MSC mobilization, migration, homing, adhesion and retention, regulates angiogenesis and vasculogenesis through existing endothelial cells (ECs) and endothelial progenitor cells (EPCs). Additionally, MSCs have the ability to differentiate into multiple cell lineages and can be mobilized and migrate to ischemic tissue to differentiate into ECs, pericytes and smooth muscle cells in some degree, which are necessary components of blood vessels. These characteristics of MSCs support the view that these cells improve ischemic myocardium through angiogenesis and vasculogenesis. In this review, the results of recent clinical and preclinical studies are discussed to illustrate the processes and mechanisms of neovascularization in ischemic heart disease.

Vasculogenesis from Human Dental Pulp Stem Cells Grown in Matrigel with Fully Defined Serum-Free Culture Media

The generation of vasculature is one of the most important challenges in tissue engineering and regeneration. Human dental pulp stem cells (hDPSCs) are some of the most promising stem cell types to induce vasculogenesis and angiogenesis as they not only secrete vascular endothelial growth factor (VEGF) but can also differentiate in vitro into both endotheliocytes and pericytes in serum-free culture media. Moreover, hDPSCs can generate complete blood vessels containing both endothelial and mural layers in vivo, upon transplantation into the adult brain. However, many of the serum free media employed for the growth of hDPSCs contain supplements of an undisclosed composition. This generates uncertainty as to which of its precise components are necessary and which are dispensable for the vascular differentiation of hDPSCs, and also hinders the transfer of basic research findings to clinical cell therapy. In this work, we designed and tested new endothelial differentiation media with a fully defined composition using standard basal culture media supplemented with a mixture of B27, heparin and growth factors, including VEGF-A165 at different concentrations. We also optimized an in vitro Matrigel assay to characterize both the ability of hDPSCs to differentiate to vascular cells and their capacity to generate vascular tubules in 3D cultures. The description of a fully defined serum-free culture medium for the induction of vasculogenesis using human adult stem cells highlights its potential as a relevant innovation for tissue engineering applications. In conclusion, we achieved efficient vasculogenesis starting from hDPSCs using serum-free culture media with a fully defined composition, which is applicable for human cell therapy purposes.

ITGB1 promotes the chondrogenic differentiation of human adipose-derived mesenchymal stem cells by activating the ERK signaling

Adipose-derived mesenchymal stem cell (ADSC) with a high capacity of chondrogenic differentiation was a promising candidate for cartilage defect treatment. This study's objective is to study the roles of integrin β1 (ITGB1) in regulating ADSC chondrogenic differentiations as well as the underlying mechanisms. The identity of ADSC was confirmed by flow cytometry. ITGB1 gene was overexpressed in human ADSC (hADSC) by transfection with LV003-recombinant plasmids. Gene mRNA and protein levels were examined using quantitative RT-PCR and western blotting, respectively. Differentially expressed mRNAs and proteins were characterized by next-generation RNA sequencing and label-free quantitative proteomics, respectively. ERK signaling and AKT signaling in hADSCs were inhibited by treating with SCH772984 and GSK690693, respectively. ITGB1 gene overexpression substantially increased collagen type II alpha 1 chain (COL2A1), aggrecan (ACAN), and SRY-box transcription factor 9 (SOX9) expression but suppressed collagen type I alpha 1 chain (COL1A1) expression in hADSCs. Next-generation RNA sequencing identified a total of 246 genes differentially expressed in hADSCs by ITGB1 overexpression, such as 183 upregulated and 63 downregulated genes. Label-free proteomics characterized 34 proteins differentially expressed in ITGB1-overexpressing hADSCs. Differentially expressed genes and proteins were enriched by different biological processes such as cell adhesion and differentiation and numerous signaling pathways such as the ERK signaling pathway. ERK inhibitor treatment caused substantially enhanced chondrogenic differentiation in ITGB1-overexpressing hADSCs. ITGB1 promoted the chondrogenic differentiation of human ADSCs via the activation of the ERK signaling pathway.

Growth Factors and Small-molecule Compounds in Derivation of Endothelial Lineages from Dental Stem Cells

INTRODUCTION

Incorporating fully assembled microvascular networks into bioengineered dental pulp constructs can significantly enhance functional blood flow and tissue survival upon transplantation. Endothelial cells (ECs), cellular building blocks of vascular tissue, play an essential role in the process of prevascularization. However, obtaining sufficient ECs from a suitable source for translational application is challenging. Dental stem cells (DSCs), which exhibit a robust proliferative ability and immunocompatibility because of their autologous origin, could be a promising alternative cell source for the derivation of endothelial lineages. Under specific culture conditions, DSCs differentiate into osteo/odontogenic, adipogenic, chondrogenic, and neurogenic cell lineages.

METHODS

Recently, a new approach has been developed to directly reprogram cells using chemical cocktails and growth factors. Compared with the traditional reprogramming approach based on the forced expression of exogenous transcription factors, the chemical strategy avoids the risk associated with lentiviral transduction while offering a more viable methodology to drive cell lineage switch. The aim of this review was to unveil the concept of the use of small-molecule compounds and growth factors modulating key signaling pathways to derive ECs from DSCs.

RESULTS

In addition, our preliminary study showed that stem cells from the apical papilla could be induced into EC-like cells using small-molecule compounds and growth factors. These EC-like cells expressed endothelial specific genes (CD31 and VEGFR2) and proteins (CD31, VEGF receptor 2, and vascular endothelial cadherin) as well as gave rise to vessel-like tubular structures in vitro.

CONCLUSIONS

Our preliminary results suggest that chemical reprogramming might offer a novel way to generate EC-like cells from dental stem cells.

Derivation of endothelial cells from porcine induced pluripotent stem cells by optimized single layer culture system

Regenerative therapy holds great promise in the development of cures of some untreatable diseases such as cardiovascular diseases, and pluripotent stem cells (PSCs) including induced PSCs (iPSCs) are the most important regenerative seed cells. Recently, differentiation of human PSCs into functional tissues and cells in vitro has been widely reported. However, although porcine reports are rare they are quite essential, as the pig is an important animal model for the in vitro generation of human organs. In this study, we reprogramed porcine embryonic fibroblasts into porcine iPSCs (piPSCs), and differentiated them into cluster of differentiation 31 (CD31)-positive endothelial cells (ECs) (piPSC-derived ECs, piPS-ECs) using an optimized single-layer culture method. During differentiation, we observed that a combination of GSK3β inhibitor (CHIR99021) and bone morphogenetic protein 4 (BMP4) promoted mesodermal differentiation, resulting in higher proportions of CD31-positive cells than those from separate CHIR99021 or BMP4 treatment. Importantly, the piPS-ECs showed comparable morphological and functional properties to immortalized porcine aortic ECs, which are capable of taking up low-density lipoprotein and forming network structures on Matrigel. Our study, which is the first trial on a species other than human and mouse, has provided an optimized single-layer culture method for obtaining ECs from porcine PSCs. Our approach can be beneficial when evaluating autologous EC transplantation in pig models.

TWIST1-Reprogrammed Endothelial Cell Transplantation Potentiates Neovascularization-Mediated Diabetic Wound Tissue Regeneration

Hypovascularized diabetic nonhealing wounds are due to reduced number and impaired physiology of endogenous endothelial progenitor cell (EPC) population that limits their recruitment and mobilization at the wound site. For enrichment of the EPC repertoire from nonendothelial precursors, abundantly available mesenchymal stromal cells (MSC) were reprogrammed into induced endothelial cells (iEC). We identified cell signaling molecular targets by meta-analysis of microarray data sets. BMP-2 induction leads to the expression of inhibitory Smad 6/7-dependent negative transcriptional regulation of ID1, rendering the latter's reduced binding to TWIST1 during transdifferentiation of Wharton jelly-derived MSC (WJ-MSC) into iEC. TWIST1, in turn, regulates endothelial gene transcription, positively of proangiogenic KDR and negatively, in part, of antiangiogenic SFRP4 Twist1 reprogramming enhanced the endothelial lineage commitment of WJ-MSC and increased the vasculogenic potential of reprogrammed endothelial cells (rEC). Transplantation of stable TWIST1 rEC into a type 1 and 2 diabetic full-thickness splinted wound healing murine model enhanced the microcirculatory blood flow and accelerated the wound tissue regeneration. An increased or decreased colocalization of GFP with KDR/SFRP4 and CD31 in the regenerated diabetic wound bed with TWIST1 overexpression or silencing (piLenti-TWIST1-shRNA-GFP), respectively, further confirmed improved neovascularization. This study depicted the reprogramming of WJ-MSC into rEC using unique transcription factor TWIST1 for an efficacious cell transplantation therapy to induce neovascularization-mediated diabetic wound tissue regeneration.

Mesenchymal stem cell-derived exosomal miR-223 regulates neuronal cell apoptosis

Hypoxia limits the survival and function of neurons in the development of Alzheimer’s diseases. Exosome-dependent intercellular communication is an emerging signaling mechanism involved in tissue repair and regeneration; however, the effect and underlying mechanism of mesenchymal stem cell-derived exosomes in regulating neuronal cell apoptosis have not been determined. Here, we showed that the establishment of an AD cell model was accompanied by increased HIF-1α expression and cell apoptosis, impaired cell migration, and decreased miR-223. MSC-derived exosomes were internalized by the AD cell coculture model in a time-dependent manner, resulting in reduced cell apoptosis, enhanced cell migration and increased miR-223, and these effects were reversed by KC7F2, a hypoxic inhibitor. Furthermore, MSC-derived exosomal miR-223 inhibited the apoptosis of neurons in vitro by targeting PTEN, thus activating the PI3K/Akt pathway. In addition, exosomes isolated from the serum of AD patients promoted cell apoptosis. In short, our study showed that MSC-derived exosomal miR-223 protected neuronal cells from apoptosis through the PTEN-PI3K/Akt pathway and provided a potential therapeutic approach for AD.

Role of VEGFs in metabolic disorders

Obesity and metabolic disorders are important public health problems. In this review, the role of vasculature network and VEGF in the adipose tissue maintenance and supplementation is discussed. Angiogenesis is a key process implicated in regulation of tissues homeostasis. Dysregulation of new blood vessels formation may be crucial and contribute to the onset of several pathological conditions, including metabolic syndrome-associated disorders. Adipose tissue homeostasis is fine regulated by vascular network. Vessels support adipose structure. Vasculature modulates the balance between positive and negative regulator factors. In white adipose tissue, vascular endothelial growth factor (VEGF) controls the metabolic activities of adipocytes promoting the trans-differentiation from white to beige phenotype. Trans-differentiation results in an increase of energy consumption. VEGF exerts an opposite effect on brown adipose tissue, where VEGF increases oxygen supply and improves energy expenditure inducing the whitening of adipocytes.

Natural Histogel-Based Bio-Scaffolds for Sustaining Angiogenesis in Beige Adipose Tissue

In the treatment of obesity and its related disorders, one of the measures adopted is weight reduction by controlling nutrition and increasing physical activity. A valid alternative to restore the physiological function of the human body could be the increase of energy consumption by inducing the browning of adipose tissue. To this purpose, we tested the ability of Histogel, a natural mixture of glycosaminoglycans isolated from animal Wharton jelly, to sustain the differentiation of adipose derived mesenchymal cells (ADSCs) into brown-like cells expressing UCP-1. Differentiated cells show a higher energy metabolism compared to undifferentiated mesenchymal cells. Furthermore, Histogel acts as a pro-angiogenic matrix, induces endothelial cell proliferation and sprouting in a three-dimensional gel in vitro, and stimulates neovascularization when applied in vivo on top of the chicken embryo chorioallantoic membrane or injected subcutaneously in mice. In addition to the pro-angiogenic activity of Histogel, also the ADSC derived beige cells contribute to activating endothelial cells. These data led us to propose Histogel as a promising scaffold for the modulation of the thermogenic behavior of adipose tissue. Indeed, Histogel simultaneously supports the acquisition of brown tissue markers and activates the vasculature process necessary for the correct function of the thermogenic tissue. Thus, Histogel represents a valid candidate for the development of bioscaffolds to increase the amount of brown adipose tissue in patients with metabolic disorders.

Endothelial progenitor cell therapy for chronic wound tissue regeneration

Despite advancements in wound care, healing of chronic diabetic wounds remains a great challenge for the clinical fraternity because of the intricacies of the healing process. Due to the limitations of existing treatment strategies for chronic wounds, stem/progenitor cell transplantation therapies have been explored as an alternative for tissue regeneration at the wound site. The non-healing phenotype of chronic wounds is directly associated with lack of vascularization. Therefore, endothelial progenitor cell (EPC) transplantation is proving to be a promising approach for the treatment of hypo-vascular chronic wounds. With the existing knowledge in EPC biology, significant efforts have been made to enrich EPCs at the chronic wound site, generating EPCs from somatic cells, induced pluripotent stem cells (iPSCs) using transcription factors, or from adult stem cells using chemicals/drugs for use in transplantation, as well as modulating the endogenous dysfunctional/compromised EPCs under diabetic conditions. This review mainly focuses on the pre-clinical and clinical approaches undertaken to date with EPC-based translational therapy for chronic diabetic as well as non-diabetic wounds to evaluate their vascularity-mediated regeneration potential.

Epiregulin enhances odontoblastic differentiation of dental pulp stem cells via activating MAPK signalling pathway

Objectives

The odontoblastic differentiation of dental pulp stem cells (DPSCs) contributes to tertiary dentin formation. Our previous study indicated that epiregulin (EREG) enhanced odontogenesis potential of dental pulp. Here, we explored the effects of EREG during DPSC odontoblastic differentiation.

Methods

The changes in EREG were detected during tertiary dentin formation. DPSCs were treated with recombinant human EREG (rhEREG), EREG receptor inhibitor gefitinib and short hairpin RNAs. The odontoblastic differentiation was assessed with ALP staining, ALP activity assay, alizarin red S staining and real‐time RT‐PCR of DSPP, OCN, RUNX2 and OSX. Western blot was conducted to examine the levels of p38 mitogen‐activated protein kinase (p38 MAPK), c‐Jun N‐terminal kinase (JNK) and extracellular signal‐regulated kinase 1/2 (Erk1/2). The expression of EREG and odontoblastic differentiation‐related markers was investigated in human dental pulp from teeth with deep caries and healthy teeth.

Results

Epiregulin was upregulated during tertiary dentin formation. rhEREG enhanced the odontoblastic differentiation of DPSCs following upregulated p38 MAPK and Erk1/2 phosphorylation, but not JNK, whereas depletion of EREG suppressed DPSC differentiation. Gefitinib decreased odontoblastic differentiation with decreased phosphorylation of p38 MAPK and Erk1/2. And suppression of p38 MAPK and Erk1/2 pathways attenuated DPSC differentiation. In human dental pulp tissue, EREG upregulation in deep caries correlates with odontoblastic differentiation enhancement.

Conclusion

Epiregulin is released during tertiary dentin formation. And EREG enhanced DPSC odontoblastic differentiation via MAPK pathways.

Afatinib, an EGFR inhibitor, decreases EMT and tumorigenesis of Huh‑7 cells by regulating the ERK‑VEGF/MMP9 signaling pathway

Transcatheter arterial embolization (TAE) therapy has been used in the treatment of inoperable hepatocellular carcinoma (HCC). However, tumor recurrence and metastasis are common in patients after TAE, and these processes may be caused by circulating tumor cells (CTCs). Epithelial-mesenchymal transition (EMT) serves important roles in CTCs, and abnormal expression and activation of epidermal growth factor receptor (EGFR) is common in cancer cells. Afatinib is an EGFR-tyrosine kinase inhibitor (TKI). The present study aimed to investigate the effects of afatinib on EMT and tumorigenesis in HCC cells. Western blot analysis suggested that afatinib was able to effectively suppress overactivation of EGFR. Moreover, the expression levels of EMT- and metastasis-associated genes were found to be modulated by afatinib through EGFR inhibition. In addition, Cell Counting Kit-8 and Transwell assays suggested that the viability, migration and invasion of HCC cells were inhibited by afatinib through EGFR inhibition. Furthermore, the activity of the ERK signaling pathway and the expression levels of vascular endothelial growth factor (VEGF) and matrix metalloproteinase 9 (MMP9) were decreased following treatment with afatinib in vitro. Collectively, the present results suggested that the inhibitory effects of afatinib on EMT and tumorigenesis may be associated with the ERK-VEGF/MMP9 signaling pathway. The present study provides new insights into understanding the mechanism underlying HCC and may facilitate the development of novel therapeutic strategies to treat HCC recurrence.

Aflibercept regulates retinal inflammation elicited by high glucose via the PlGF/ERK pathway

Diabetic retinopathy (DR) is a secondary complication of diabetes. DR can cause irreversible blindness, and its pathogenesis is considered multifactorial. DR can progress from non-proliferative DR to proliferative DR, characterized by retinal neovascularization. The main cause of vision loss in diabetic patients is diabetic macular edema, caused by vessel leakage and blood retinal barrier breakdown. Currently, aflibercept is an anti-VEGF approved for diabetic macular edema. Aflibercept can bind several members of vascular permeability factors, namely VEGF-A, B, and PlGF. We analyzed the aflibercept-PlGF complex at molecular level, through an in silico approach. In order to explore the role of PlGF in DR, we treated primary human retinal endothelial cells (HRECs) and mouse retinal epithelial cells (RPEs) with aflibercept and an anti-PlGF antibody. We explored the hypothesis that aflibercept has anti-inflammatory action through blocking of PlGF signaling and the ERK axis in an in vitro and in vivo model of DR. Both aflibercept and the anti-PlGF antibody exerted protective effects on retinal cells, by inhibition of the ERK pathway. Moreover, aflibercept significantly decreased (p < 0.05) the expression of TNF-α in an in vitro and in vivo model of DR. Therefore, our data suggest that inhibition of PlGF signaling, or a selective blocking, may be useful in the management of early phases of DR when the inflammatory process is largely involved.

Propofol attenuated TNF-α-modulated occludin expression by inhibiting Hif-1α/ VEGF/ VEGFR-2/ ERK signaling pathway in hCMEC/D3 cells

Background

The levels of tight junction proteins (TJs), especially occludin, correlate with blood-brain barrier (BBB) disruption caused by inflammation in central nervous system (CNS). It has been reported that propofol, the most commonly used anesthetic, could inhibit inflammation response in CNS. In this study, we investigated the effects of tumor necrosis factor-α (TNF-α) and propofol on occludin expression in human cerebral microvascular endothelial cell line, D3 clone (hCMEC/D3 cells), and explored the underlying mechanisms.

Methods

The hCMEC/D3 cells were treated with propofol, followed by TNF-α. The expression and phosphorylation of Hif-1α, VEGF, VEGFR-2, ERK, p38MAPK and occludin were measured by Western blot analysis. The cell viability of hCMEC/D3 cells was measured by cell counting kit-8.

Results

TNF-α (10 ng/ml, 4 h) significantly decreased the expression of occludin, which was attenuated by propofol (25 μM). TNF-α induced Hif-1α/VEGF/VEGFR-2/ERK signaling pathway, while propofol could inhibit it. TNF-α induced the phosphorylation of p38MAPK, while propofol had no effect on it. In addition, the inhibitors of Hif-1α, VEGFR-2, and ERK could reduce the effect of TNF-α on occludin expression.

Conclusion

TNF-α could decrease the expression of occludin via activating Hif-1α/ VEGF/ VEGFR-2/ ERK signaling pathway, which was attenuated by propofol.

Electronic supplementary material

The online version of this article (10.1186/s12871-019-0788-5) contains supplementary material, which is available to authorized users.

3D Human Periodontal Stem Cells and Endothelial Cells Promote Bone Development in Bovine Pericardium-Based Tissue Biomaterial

Bone defects repair represents a public and urgent problem in clinical practice, in fact, every year, more than two million patients required new treatments for bone injuries. Today a complete vascularization is strategic in bone formation, representing a new frontier for clinical application. Aim of this research has been developed a three-dimensional (3D) coculture platform using a bovine pericardium collagen membrane (BioR) loaded with human periodontal ligament stem cells (hPDLSCs) and endothelial differentiated cells from hPDLSCs (E-hPDLSCs) able to undergo toward osteoangiogenesis differentiation process. First, we have characterized at confocal laser scanning microscopy (CLSM) level the E-hPDLSCs phenotype profile, through CD31 and CD34 markers expression and the ability to tube vessel formation. Real Time-Polimerase Chain Reaction (RT-PCR) and western blotting analyses revealed the upregulation of Runt-related transcription factor 2 (RUNX2), Collagen 1A1 (COL1A1), Vascular Endothelial Growth Factor-A (VEGF-A) genes and proteins in the living construct composed by hPDLSCs + E-hPDSCs/BioR. Human PDLSCs + E-hPDLSCs/BioR construct showed also an enhacement of de novo synthesis of osteocalcin. Given that, the extracellular-signal-regulated kinase (ERK)/mitogen activated protein kinase (MAPK) transduction signaling was involved in the osteogenesis and angiogenesis process, the ERK1/2 protein level at biochemical level, in our experimental model, has been investigated. Our results evidenced an upregulation of ERK1/2 proteins level born in the living construct. In conclusion, we believe that the use of the hPDLSCs and E-hPDLSCs coculture togheter with BioR as substrate, could represent an efficient model able to activate through ERK1/2 signaling pathway the osteoangiogenesis process, and then representing a new potential engineered platform for surgeons during the repair and the healing of bone defects.

Human Dental Pulp Stem Cells Grown in Neurogenic Media Differentiate Into Endothelial Cells and Promote Neovasculogenesis in the Mouse Brain

Dental pulp stem cells (DPSCs) have the capacity to give rise to cells with neuronal-like phenotypes, suggesting their use in brain cell therapies. In the present work, we wanted to address the phenotypic fate of adult genetically unmodified human DPSCs cultured in Neurocult^TM (Stem Cell Technologies), a cell culture medium without serum which can be alternatively supplemented for the expansion and/or differentiation of adult neural stem cells (NSCs). Our results show that non-genetically modified human adult DPSCs cultured with Neurocult NS-A proliferation supplement generated neurosphere-like dentospheres expressing the NSC markers Nestin and glial fibrillary acidic protein (GFAP), but also the vascular endothelial cell marker CD31. Remarkably, 1 month after intracranial graft into athymic nude mice, human CD31+/CD146+ and Nestin+ DPSC-derived cells were found tightly associated with both the endothelial and pericyte layers of brain vasculature, forming full blood vessels of human origin which showed an increased laminin staining. These results are the first demonstration that DPSC-derived cells contributed to the generation of neovasculature within brain tissue, and that Neurocult and other related serum-free cell culture media may constitute a fast and efficient way to obtain endothelial cells from human DPSCs.

Novel multitarget inhibitors with antiangiogenic and immunomodulator properties

By means of docking studies, seventeen compounds T.1-T17 have been designed and evaluated as multitarget inhibitors of VEGFR-2 and PD-L1 proteins in order to overcome resistance phenomena offered by cancer. All these designed molecules display a urea moiety as a common structural feature and eight of them (T.1-T8) further contain a 1,2,3-triazol moiety. The antiproliferative activity of these molecules on several tumor cell lines (HT-29, MCF-7, HeLa, A549, HL-60), on the endothelial cell line HMEC-1 and on the non-tumor cell line HEK-293 has been determined. The urea derivatives were also evaluated for their antiangiogenic properties, whereby their ability to inhibit tubulogenesis and kinase activity employing flow cytometry, ELISA, immunofluorescence and western blot techniques was measured. In addition, these techniques were also employed to investigate the immunomodulator action of the synthetic compounds on the inhibition of PD-L1 and c-Myc proteins. Compound T.2, 1-(3-chlorophenyl)-3-(2-(4-(4-methoxybenzyl)-1H-1,2,3-triazol-1-yl)ethyl)urea, has shown similar results to sorafenib in both down-regulation of VEGFR-2 and inhibition of the kinase activity of this receptor. Furthermore, compound T.14, (E)-1-(4-chlorophenyl)-3-(3-(4-methoxystyryl)phenyl)urea, improves the effect of T.2 as regards tube formation of endothelial cells and inhibition of VEGFR-2 tyrosine kinase activity. In addition, T.14 improves the effect of the experimental drug BMS-8 in the inhibition of PD-L1 and c-Myc proteins.

MicroRNA let-7b inhibits keratinocyte differentiation by targeting IL-6 mediated ERK signaling in psoriasis

Background

The extensive involvement of microRNA (miRNA) in the pathophysiology of psoriasis is well documented. However, in order for this information to be useful in therapeutic manipulation of miRNA levels, it is essential that detailed functional mechanisms are elucidated. This study aimed to explore the effects of IL-6 targeting by let-7b and ERK1/2 mediated signaling on keratinocyte differentiation in psoriasis.

Methods

Following imiquimod cream (IMQ) application to let-7b^TG (keratinocyte-specific let-7b overexpression mouse) and control mice for 7 days, we analyzed erythema, scaling and thickening of skin. A dual luciferase reporter assay and bioinformatics was carried out to detect target gene of let-7b. Additionally, the differentiation markers were measured. Immunohistochemistry analyses demonstrate a relationship of let-7b with IL-6 and ERK signaling.

Results

we found let-7b^TG inhibits acanthosis and reduces the disease severity by treatment with IMQ compared to wild-type mice. Further study illustrated that let-7b promotes differentiation of keratinocytes in vivo and in vitro. Using bioinformatics and reporter gene assays, we found that IL-6 is a target gene of let-7b. In psoriasis, high expression levels of IL-6 lead to increased acivation of p-ERK1/2. High levels of let-7b^TG transgene expression suppresses IL-6 expression and leads to increased keratinocyte differentiation. Moreover, let-7b acts as an upstream negative regulator of the ERK signaling pathway in keratinocytes of psoriasis.

Conclusions

Our result reveals a previously unknown mechanism for regulation of IL-6 levels during psoriasis by let-7b and highlights a critical role for the ERK1/2 signaling pathway in epidermal differentiation during psoriasis.

Trial registration

The ethical approval for this study was from the Affiliated Hospital of Medical University of Anhui _ Fast_ PJ2017–11–14.

Electronic supplementary material

The online version of this article (10.1186/s12964-018-0271-9) contains supplementary material, which is available to authorized users.

Vascular endothelial growth factor over-expressed mesenchymal stem cells-conditioned media ameliorate palmitate-induced diabetic endothelial dysfunction through PI-3K/AKT/m-TOR/eNOS and p38/MAPK signaling pathway

In the pathogenesis of diabetes mellitus (DM), islet microvasculares are severely damaged due to glucolipotoxicity and other reasons. Vascular endothelial growth factor (VEGF) is an indispensable and specific angiogenic factor in the pathogenesis and treatment of diabetic islet microvascular disease. Mesenchymal stem cells (MSCs) are regarded as a promising treatment of diabetes because of their immunosuppressive effect and multipotential differentiation potency. In this study, we tested whether MSCs over-expressing VEGF conditioned medium (MSC-VEGF-CM) could ameliorate pancreatic islet endothelial cells (MS-1) dysfunction induced by a common diabetic inducer palmitate (PA). We found that cell survival and migration were restrained by PA and partly repaired by the pro-protected of MSC-VEGF-CM. Meanwhile, PI-3K/AKT/m-TOR/eNOS and p38/MAPK signaling pathways were also up-regulated. Though apoptosis-related proteins, caspase-3 and caspase-9, had no significantly suppressed between MSC-VEGF-CM and MSC-CM alone, the expression levels of vascular surface factors such as CD31, VE-cadherin, occludin and ICAM-1, were remarkably up-regulated by the pro-protected of MSC-VEGF-CM. Our data suggested that MSC-VEGF-CM had therapeutic effect on the PA-induced dysfunction through the re-activation of PI-3K/AKT/m-TOR/eNOS and p38/MAPK signaling pathways.