Fucoidan improves bioactivity and vasculogenic potential of mesenchymal stem cells in murine hind limb ischemia associated with chronic kidney disease

Histological evaluation of renal progenitor/stem cells, renal mesenchymal stem-like cells, and endothelial progenitor cells in chronic kidney disease and end-stage renal disease, and molecular docking analysis of drug-receptor interactions

Chronic kidney disease (CKD) and end-stage renal disease (ESRD) are prevalent and debilitating conditions with a significant impact on patients' quality of life. In this study, we conducted a comprehensive investigation into the histological characteristics of renal progenitor/stem cells (RPCs), renal mesenchymal stem-like cells, and endothelial progenitor cells (EPCs) in CKD and ESRD patients. Additionally, we performed a molecular docking analysis to explore potential drug-receptor interactions involving common medications prescribed to CKD patients. Our histological examination revealed a noteworthy increase in the number of CD24- and CD133-positive cells in CKD and ESRD patients, representing RPCs. These cells are implicated in kidney repair and regeneration, underscoring their potential role in CKD management. Moreover, we observed an elevation in the number of EPCs within the kidneys of CKD and ESRD patients, suggesting a protective role of EPCs in kidney preservation. The molecular docking analysis unveiled intriguing insights into potential drug interventions. Notably, digoxin exhibited the highest in-silico binding affinity to numerous receptors associated with the functions of RPCs, renal mesenchymal stem-like cells, and EPCs, emphasizing the potential multifaceted effects of this cardiac glycoside in CKD patients. Other drugs, including apixaban, glimepiride, and glibenclamide, also displayed strong in-silico affinities to specific receptors, indicating their potential influence on various renal cell functions. In conclusion, this study provides valuable insights into the histological alterations in renal cell populations in CKD and ESRD patients and underscores the potential roles of RPCs and EPCs in kidney repair and preservation. The molecular docking analysis reveals the complex interactions between common drugs and renal cells, suggesting the need for further in-vitro and in-vivo research to fully understand these relationships. These findings contribute to our understanding of CKD and offer new avenues for research into potential therapeutic interventions.

Administration of stem cells against cardiovascular diseases with a focus on molecular mechanisms: Current knowledge and prospects

Cardiovascular diseases (CVDs) are a serious global concern for public and human health. Despite the emergence of significant therapeutic advances, it is still the leading cause of death and disability worldwide. As a result, extensive efforts are underway to develop practical therapeutic approaches. Stem cell-based therapies could be considered a promising strategy for the treatment of CVDs. The efficacy of stem cell-based therapeutic approaches is demonstrated through recent laboratory and clinical studies due to their inherent regenerative properties, proliferative nature, and their capacity to differentiate into different cells such as cardiomyocytes. These properties could improve cardiovascular functioning leading to heart regeneration. The two most common types of stem cells with the potential to cure heart diseases are induced pluripotent stem cells (iPSCs) and mesenchymal stem cells (MSCs). Several studies have demonstrated the use, efficacy, and safety of MSC and iPSCs-based therapies for the treatment of CVDs. In this study, we explain the application of stem cells, especially iPSCs and MSCs, in the treatment of CVDs with a focus on cellular and molecular mechanisms and then discuss the advantages, disadvantages, and perspectives of using this technology in the treatment of these diseases.

Immunopotentiating Activity of Fucoidans and Relevance to Cancer Immunotherapy

Fucoidans, discovered in 1913, are fucose-rich sulfated polysaccharides extracted mainly from brown seaweed. These versatile and nontoxic marine-origin heteropolysaccharides have a wide range of favorable biological activities, including antitumor, immunomodulatory, antiviral, antithrombotic, anticoagulant, antithrombotic, antioxidant, and lipid-lowering activities. In the early 1980s, fucoidans were first recognized for their role in supporting the immune response and later, in the 1990s, their effects on immune potentiation began to emerge. In recent years, the understanding of the immunomodulatory effects of fucoidan has expanded significantly. The ability of fucoidan(s) to activate CTL-mediated cytotoxicity against cancer cells, strong antitumor property, and robust safety profile make fucoidans desirable for effective cancer immunotherapy. This review focusses on current progress and understanding of the immunopotentiation activity of various fucoidans, emphasizing their relevance to cancer immunotherapy. Here, we will discuss the action of fucoidans in different immune cells and review how fucoidans can be used as adjuvants in conjunction with immunotherapeutic products to improve cancer treatment and clinical outcome. Some key rationales for the possible combination of fucoidans with immunotherapy will be discussed. An update is provided on human clinical studies and available registered cancer clinical trials using fucoidans while highlighting future prospects and challenges.

The potential of plant extracts in cell therapy

Cell therapy is the frontier technology of biotechnology innovation and the most promising method for the treatment of refractory diseases such as tumours. However, cell therapy has disadvantages, such as toxicity and poor therapeutic effects. Plant extracts are natural, widely available, and contain active small molecule ingredients that are widely used in the treatment of various diseases. By studying the effect of plant extracts on cell therapy, active plant extracts that have positive significance in cell therapy can be discovered, and certain contributions to solving the current problems of attenuation and adjuvant therapy in cell therapy can be made. Therefore, this article reviews the currently reported effects of plant extracts in stem cell therapy and immune cell therapy, especially the effects of plant extracts on the proliferation and differentiation of mesenchymal stem cells and nerve stem cells and the potential role of plant extracts in chimeric antigen receptor T-cell immunotherapy (CAR-T) and T-cell receptor modified T-cell immunotherapy (TCR-T), in the hope of encouraging further research and clinical application of plant extracts in cell therapy.

Effects of Fucoidan Powder Combined with Mineral Trioxide Aggregate as a Direct Pulp-Capping Material

The development of direct pulp-capping materials with favorable biological and structural properties is an important goal in restorative dentistry. Fucoidan is a sulfated, fucose-containing polysaccharide obtained from brown seaweed, with a wide range of applications; however, its use as a direct pulp-capping material has not been examined. This study aimed to evaluate the mechanical, physical, and biological effects of fucoidan combined with conventional mineral trioxide aggregate (MTA) for direct pulp capping. The capping materials were created using Portland cement (80 wt%) and zirconium oxide (20 wt%) as base components, compared with base components plus 5 wt% fucoidan (PZF5) and base components plus 10 wt% fucoidan (PZF10). The initial and final setting time, compressive strength, chemical components, cell viability, adhesion, migration, osteogenesis, and gene expression were analyzed. Fucoidan significantly reduced the initial and final setting time, regardless of quantity. However, the compressive strength was lower for PZF5. Sulfur levels increased with fucoidan. The biological activity improved, especially in the PZF5 group. Cell migration, Alizarin Red S staining, and alkaline phosphatase activity were upregulated in the PZF5 group. Fucoidan is a useful regenerative additive for conventional pulp-capping materials because it reduces the setting time and improves cell migration and osteogenic ability.

Anti-Inflammatory Mechanisms of Fucoidans to Treat Inflammatory Diseases: A Review

Fucoidans are sulfated heteropolysaccharides found in the cell walls of brown seaweeds (Phaeophyceae) and in some marine invertebrates. Generally, fucoidans are composed of significant amounts of L-fucose and sulfate groups, and lesser amounts of arabinose, galactose, glucose, glucuronic acid, mannose, rhamnose, and xylose. In recent years, fucoidans isolated from brown seaweeds have gained considerable attention owing to their promising bioactive properties such as antioxidant, immunomodulatory, anti-inflammatory, antiobesity, antidiabetic, and anticancer properties. Inflammation is a complex immune response that protects the organs from infection and tissue injury. While controlled inflammatory responses are beneficial to the host, leading to the removal of immunostimulants from the host tissues and restoration of structural and physiological functions in the host tissues, chronic inflammatory responses are often associated with the pathogenesis of tumor development, arthritis, cardiovascular diseases, diabetes, obesity, and neurodegenerative diseases. In this review, the authors mainly discuss the studies since 2016 that have reported anti-inflammatory properties of fucoidans isolated from various brown seaweeds, and their potential as a novel functional material for the treatment of inflammatory diseases.

Fucoidan: a promising agent for brain injury and neurodegenerative disease intervention

Brain injury and neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis are urgent medical problems, which severely threaten the life quality of patients and their carers. However, there are currently no effective therapies. Fucoidan is a natural compound found in brown algae and some animals, which has multiple biological and pharmacological activities, such as antioxidant, anti-tumor, anti-coagulant, anti-thrombotic, immunoregulatory, anti-viral, and anti-inflammatory effects. A growing number of studies have shown that fucoidan also exerts a neuroprotective function. Particularly, recent findings have indicated that fucoidan could slow down the neurodegenerative processes and show protective effects against brain injury, which might be of therapeutic value for intervening in brain injury and neurodegenerative diseases. In this review, we have discussed the pharmacokinetics of fucoidan as well as the molecular mechanisms by which fucoidan exerts its neuroprotective effect on some neurological disorders. Along with this, we have also summarized the potential benefits of fucoidan in combination with other drugs in the treatment of neurodegenerative diseases and brain injury. Although the extraction process of fucoidan has been improved well, more efforts should be devoted to the translational research and clinical trials of fucoidan in the near future.

Natural Products in the Prevention of Metabolic Diseases: Lessons Learned from the 20th KAST Frontier Scientists Workshop

The incidence of metabolic and chronic diseases including cancer, obesity, inflammation-related diseases sharply increased in the 21st century. Major underlying causes for these diseases are inflammation and oxidative stress. Accordingly, natural products and their bioactive components are obvious therapeutic agents for these diseases, given their antioxidant and anti-inflammatory properties. Research in this area has been significantly expanded to include chemical identification of these compounds using advanced analytical techniques, determining their mechanism of action, food fortification and supplement development, and enhancing their bioavailability and bioactivity using nanotechnology. These timely topics were discussed at the 20th Frontier Scientists Workshop sponsored by the Korean Academy of Science and Technology, held at the University of Hawaii at Manoa on 23 November 2019. Scientists from South Korea and the U.S. shared their recent research under the overarching theme of Bioactive Compounds, Nanoparticles, and Disease Prevention. This review summarizes presentations at the workshop to provide current knowledge of the role of natural products in the prevention and treatment of metabolic diseases.

Ultrasound enhances the therapeutic potential of mesenchymal stem cells wrapped in greater omentum for aristolochic acid nephropathy

Background

Mesenchymal stem cells (MSCs) have been reported to promote regeneration in both subjects with acute kidney injury (AKI) and chronic kidney disease (CKD), but their efficacy remains limited, probably because most of the cells accumulate in the lungs, liver, and spleen after an intravenous infusion. Therefore, ultrasound-guided administration of MSCs represents a possible approach to solve this problem. The greater omentum is used to promote cell survival due to its rich vasculature. We hypothesized that ultrasound-guided administration of MSCs combined with greater omentum might be more curative than currently available approaches.

Methods

In this study, we established an aristolochic acid nephropathy (AAN) model by intraperitoneally administering aristolochic acid I sodium salt (AA-I) at a dose of 5 mg/kg body weight on alternate days for 4 weeks. Subsequently, a laparotomy was performed, and the left kidney from which the capsule had been removed was wrapped with the greater omentum. A dose of 2 × 10⁷ MSCs was injected into the space between the greater omentum and the left kidney. Equal amounts of MSCs were administered under ultrasound guidance every second week for a total of 4 treatments. Mice were sacrificed 4 weeks after surgery. Serum creatinine and blood urea levels were measured to assess renal function. qPCR, Western blot, and histological analyses were conducted to further investigate the therapeutic mechanism of MSCs.

Results

Ultrasound-guided injection of MSCs into the greater omentum that surrounds the kidney enriched cells in the kidney region for up to 5 days. Renal function tests indicated that MSCs improved renal function to a great extent, as reflected by decreased blood urea nitrogen and serum creatinine levels. In addition, histological analyses showed that MSCs noticeably attenuated kidney injury, as evidenced by the amelioration of tubular necrosis and peritubular interstitial fibrosis. Mitigation of renal interstitial fibrosis was further confirmed by immunohistochemistry, qPCR, and western blotting after MSC treatment. Moreover, immunofluorescence staining revealed that MSCs alleviated inflammatory responses by increasing the counts of CD206+ cells and decreasing the counts of CD68+ cells. MSC migration was initiated in response to AA-I-treated renal epithelial cells in an in vitro migration assay.

Conclusions

These findings suggested that administration of MSCs into the cavity formed by the injured kidney and the greater omentum under ultrasound guidance improved renal function, attenuated kidney injury, and mitigated renal interstitial fibrosis and inflammatory responses. Thus, this approach might be a safe and effective therapy for CKD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02243-7.

Adipose tissue and the vascularization of biomaterials: Stem cells, microvascular fragments and nanofat-a review

Tissue defects in the human body after trauma and injury require precise reconstruction to regain function. Hence, there is a great demand for clinically translatable approaches with materials that are both biocompatible and biodegradable. They should also be able to adequately integrate within the tissue through sufficient vascularization. Adipose tissue is abundant and easily accessible. It is a valuable tissue source in regenerative medicine and tissue engineering, especially with regard to its angiogenic potential. Derivatives of adipose tissue, such as microfat, nanofat, microvascular fragments, stromal vascular fraction and stem cells, are commonly used in research, but also clinically to enhance the vascularization of implants and grafts at defect sites. In plastic surgery, adipose tissue is harvested via liposuction and can be manipulated in three ways (macro-, micro- and nanofat) in the operating room, depending on its ultimate use. Whereas macro- and microfat are used as a filling material for soft tissue injuries, nanofat is an injectable viscous extract that primarily induces tissue remodeling because it is rich in growth factors and stem cells. In contrast to microfat that adds volume to a defect site, nanofat has the potential to be easily combined with scaffold materials due to its liquid and homogenous consistency and is particularly attractive for blood vessel formation. The same is true for microvascular fragments that are easily isolated from adipose tissue through collagenase digestion. In preclinical animal models, it has been convincingly shown that these vascular fragments inosculate with host vessels and subsequently accelerate scaffold perfusion and host tissue integration. Adipose tissue is also an ideal source of stem cells. It yields larger quantities of cells than any other source and is easier to access for both the patient and doctor compared with other sources such as bone marrow. They are often used for tissue regeneration in combination with biomaterials. Adipose-derived stem cells can be applied unmodified or as single cell suspensions. However, certain pretreatments, such as cultivation under hypoxic conditions or three-dimensional spheroids production, may provide substantial benefit with regard to subsequent vascularization in vivo due to induced growth factor production. In this narrative review, derivatives of adipose tissue and the vascularization of biomaterials are addressed in a comprehensive approach, including several sizes of derivatives, such as whole fat flaps for soft tissue engineering, nanofat or stem cells, their secretome and exosomes. Taken together, it can be concluded that adipose tissue and its fractions down to the molecular level promote, enhance and support vascularization of biomaterials. Therefore, there is a high potential of the individual fat component to be used in regenerative medicine.

Fucoidan Suppresses Mitochondrial Dysfunction and Cell Death against 1-Methyl-4-Phenylpyridinum-Induced Neuronal Cytotoxicity via Regulation of PGC-1α Expression

Mitochondria are considered to be the powerhouses of cells. They are the most commonly damaged organelles within dopaminergic neurons in patients with Parkinson's disease (PD). Despite the importance of protecting neuronal mitochondria in PD patients, the detailed mechanisms underlying mitochondrial dysfunction during pathogenesis and pathophysiological progression of PD have not yet been elucidated. We investigated the protective action of fucoidan against the detrimental action of 1-methyl-4-phenyl-pyridinium (MPP⁺), a neurotoxin used to model PD, in the mitochondria of SH-SY5Y neural cells. Fucoidan increased the expression of peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α) and protected the cells from MPP⁺-induced apoptosis by upregulating the 5' adenosine monophosphate-activated protein kinase (AMPK)-PGC-1α axis. These effects were blocked by the silencing of the PGC-1α axis. These results indicated that fucoidan protects SH-SY5Y cells from mitochondrial dysfunction and cell death caused by MPP⁺ treatment, via the AMPK-PGC-1α axis. These findings also suggest that fucoidan could potentially be used as a therapeutic agent for PD.

Enhancement of Functionality and Therapeutic Efficacy of Cell-Based Therapy Using Mesenchymal Stem Cells for Cardiovascular Disease

Cardiovascular disease usually triggers coronary heart disease, stroke, and ischemic diseases, thus promoting the development of functional failure. Mesenchymal stem cells (MSCs) are cells that can be isolated from various human tissues, with multipotent and immunomodulatory characteristics to help damaged tissue repair and avoidance of immune responses. Much research has proved the feasibility, safety, and efficiency of MSC-based therapy for cardiovascular disease. Despite the fact that the precise mechanism of MSCs remains unclear, their therapeutic capability to treat ischemic diseases has been tested in phase I/II clinical trials. MSCs have the potential to become an effective therapeutic strategy for the treatment of ischemic and non-ischemic cardiovascular disorders. The molecular mechanism underlying the efficacy of MSCs in promoting engraftment and accelerating the functional recovery of injury sites is still unclear. It is hypothesized that the mechanisms of paracrine effects for the cardiac repair, optimization of the niche for cell survival, and cardiac remodeling by inflammatory control are involved in the interaction between MSCs and the damaged myocardial environment. This review focuses on recent experimental and clinical findings related to cardiovascular disease. We focus on MSCs, highlighting their roles in cardiovascular disease repair, differentiation, and MSC niche, and discuss their therapeutic efficacy and the current status of MSC-based cardiovascular disease therapies.

TUDCA-treated chronic kidney disease-derived hMSCs improve therapeutic efficacy in ischemic disease via PrPC

Although autologous human mesenchymal stem cells (hMSCs) are a promising source for regenerative stem cell therapy in chronic kidney disease (CKD), the barriers associated with pathophysiological conditions limit therapeutic applicability to patients. We confirmed that level of cellular prion protein (PrP^C) in serum was decreased and mitochondria function of CKD-derived hMSCs (CKD-hMSCs) was impaired in patients with CKD. We proved that treatment of CKD-hMSCs with tauroursodeoxycholic acid (TUDCA), a bile acid, enhanced the mitochondrial function of these cells through regulation of PINK1-PrP^C-dependent pathway. In a murine hindlimb ischemia model with CKD, tail vein injection of TUDCA-treated CKD-hMSCs improved the functional recovery, including kidney recovery, limb salvage, blood perfusion ratio, and vessel formation along with restored expression of PrP^C in the blood serum of the mice. These data suggest that TUDCA-treated CKD-hMSCs are a promising new autologous stem cell therapeutic intervention that dually treats cardiovascular problems and CKD in patients.

Melatonin protects chronic kidney disease mesenchymal stem cells against senescence via PrPC -dependent enhancement of the mitochondrial function

Although mesenchymal stem cell (MSC)-based therapy is a treatment strategy for ischemic diseases associated with chronic kidney disease (CKD), MSCs of CKD patients undergo accelerated senescence, with decreased viability and proliferation upon uremic toxin exposure, inhibiting their utility as a potent stem cell source for transplantation therapy. We investigated the effects of melatonin administration in protecting against cell senescence and decreased viability induced by pathophysiological conditions near the engraftment site. MSCs harvested from CKD mouse models were treated with H₂ O₂ to induce oxidative stress. CKD-derived MSCs exhibited greater oxidative stress-induced senescence than normal-mMSCs, while melatonin protected CKD-mMSCs from H₂ O₂ and associated excessive senescence. The latter was mediated by PrP^C -dependent mitochondrial functional enhancement; melatonin upregulated PrP^C , which bound PINK1, thus promoting mitochondrial dynamics and metabolism. In vivo, melatonin-treated CKD-mMSCs survived longer, with increased secretion of angiogenic cytokines in ischemic disease engraftment sites. CKD-mMSCs are more susceptible to H₂ O₂ -induced senescence than normal-mMSCs, and melatonin administration protects CKD-mMSCs from excessive senescence by upregulating PrP^C and enhancing mitochondrial function. Melatonin showed favorable therapeutic effects by successfully protecting CKD-mMSCs from related ischemic conditions, thereby enhancing angiogenesis and survival. These results elucidate the mechanism underlying senescence inhibition by melatonin in stem cell-based therapies using mouse-derived CKD-mMSCs.

Pioglitazone Protects Mesenchymal Stem Cells against P-Cresol-Induced Mitochondrial Dysfunction via Up-Regulation of PINK-1

Mesenchymal stem cells (MSC) could be a candidate for cell-based therapy in chronic kidney disease (CKD); however, the uremic toxin in patients with CKD restricts the therapeutic efficacy of MSCs. To address this problem, we explored the effect of pioglitazone as a measure against exposure to the uremic toxin P-cresol (PC) in MSCs. Under PC exposure conditions, apoptosis of MSCs was induced, as well as PC-induced dysfunction of mitochondria by augmentation of mitofusion, reduction of mitophagy, and inactivation of mitochondrial complexes I and IV. Treatment of MSCs with pioglitazone significantly inhibited PC-induced apoptosis. Pioglitazone also prevented PC-induced mitofusion and increased mitophagy against PC exposure through up-regulation of phosphatase and tensin homolog (PTEN)-induced putative kinase 1 (PINK-1). Furthermore, pioglitazone protected against PC-induced mitochondrial dysfunction by increasing the cytochrome c oxidase subunit 4 (COX4) level and activating complexes I and IV, resulting in enhancement of proliferation. In particular, activation of nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) regulated the pioglitazone-mediated up-regulation of PINK-1. These results indicate that pioglitazone protects MSCs against PC-induced accumulated mitochondrial dysfunction via the NF-κB–PINK-1 axis under P-cresol exposure conditions. Our study suggests that pioglitazone-treated MSCs could be a candidate for MSC-based therapy in patients with CKD.

Cripto Enhances Proliferation and Survival of Mesenchymal Stem Cells by Up-Regulating JAK2/STAT3 Pathway in a GRP78-Dependent Manner

Cripto is a small glycosylphosphatidylinositol-anchored signaling protein that can detach from the anchored membrane and stimulate proliferation, migration, differentiation, vascularization, and angiogenesis. In the present study, we demonstrated that Cripto positively affected proliferation and survival of mesenchymal stem cells (MSCs) without affecting multipotency. Cripto also increased expression of phosphorylated janus kinase 2 (p-JAK2), phosphorylated signal transducer and activator of transcription 3 (p-STAT3), 78 kDa glucose-regulated protein (GRP78), c-Myc, and cyclin D1. Notably, treatment with an anti-GRP78 antibody blocked these effects. In addition, pretreatment with STAT3 short interfering RNA (siRNA) inhibited the increase in p-JAK2, c-Myc, cyclin D1, and BCL3 levels caused by Cripto and attenuated the pro-survival action of Cripto on MSCs. We also found that incubation with Cripto protected MSCs from apoptosis caused by hypoxia or H₂O₂ exposure, and the level of caspase-3 decreased by the Cripto-induced expression of B-cell lymphoma 3-encoded protein (BCL3). These effects were sensitive to down-regulation of BCL3 expression by BCL3 siRNA. Finally, we showed that Cripto enhanced expression levels of vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF), and hepatocyte growth factor (HGF). In summary, our results demonstrated that Cripto activated a novel biochemical cascade that potentiated MSC proliferation and survival. This cascade relied on phosphorylation of JAK2 and STAT3 and was regulated by GRP78. Our findings may facilitate clinical applications of MSCs, as these cells may benefit from positive effects of Cripto on their survival and biological properties.

Exendin-4 promotes proliferation of adipose-derived stem cells through PI3K/Akt-Wnt signaling pathways

Adipose-derived stem cell (ADSC) transplantation has emerged as a potential tool for the treatment of cardiovascular disease and skin wounds. However, with a limited renewal capacity and the need for mass cells during the engraftment, strategies are needed to enhance ADSC proliferative capacity. In this study, we explored the effects of Exendin-4, a glucagon-like peptide-1 analog, on the growth of ADSCs, focusing in particular on phosphatidylinositol 3-kinase (PI3K)-protein kinase B (Akt) and Wnt signaling pathways. Firstly, ADSCs were isolated and cultured in vitro. Then, flow cytometry demonstrated that ADSCs were positive for CD44, CD90 and CD29 but negative for CD31, CD34, and CD45. Exendin-4 (0-200 nM) treatment increased ADSC proliferation. In order to examine specific signaling pathways, a western blotting assay was performed. Our results demonstrate that after treated with 50 nM Exendin-4 for 48 h, the phosphorylation of PI3K, Akt, and GSK3β were increased and phosphorylation of β-catenin was decreased. From these results, we concluded that PI3K-Akt and Wnt-β-catenin signaling pathways mediate Exendin-4 induced ADSC proliferation, the function of which might contribute to the regulation of ADSC proliferation. Our findings provided new insights into the function of the mechanisms underlying Exendin-4 of ADSCs.

Co-Administration of Melatonin Effectively Enhances the Therapeutic Effects of Pioglitazone on Mesenchymal Stem Cells Undergoing Indoxyl Sulfate-Induced Senescence through Modulation of Cellular Prion Protein Expression

Background: Mesenchymal stem cells (MSCs) are a promising source for regenerative medicine. However, their therapeutic potential in patients with chronic kidney disease (CKD) is restricted by the presence of uremic toxins. To address this limitation, we explored the protective effect of melatonin and pioglitazone on MSCs undergoing senescence induced by the uremic toxin, indoxyl sulfate (IS). Methods: MSC senescence was induced by IS, and the therapeutic effects of melatonin and pioglitazone were identified. The expression of cellular prion protein (PrP^C) was suppressed by transfection of MSCs with prion protein gene (PRNP) siRNA. Subsequently, these cells were used to study the protective effects of melatonin and pioglitazone against IS-induced senescence; Results: The IS-induced senescence of MSCs was significantly reduced by co-treatment with melatonin and pioglitazone compared to treatment with melatonin or pioglitazone alone. In the presence of IS, the reduced MSC proliferation was rescued by co-treatment with melatonin and pioglitazone. Melatonin and pioglitazone enhanced the expression of peroxisome proliferator-activated receptor-γ (PPAR-γ) in MSCs, which resulted in the augmentation of PrP^C level. The inhibitory effect of the co-treatment with melatonin and pioglitazone on IS-induced senescence in MSCs was blocked by the knockdown of PRNP. In addition, the restorative effect of the co-treatment on the reduced MSC proliferation induced by IS was also blocked by the knockdown of PRNP. These findings indicate that co-treatment with melatonin and pioglitazone protected MSCs from uremic toxin-induced senescence through the regulation of the PPAR-γ-PrP^C axis. Conclusions: Our study suggests that co-treatment of MSCs with melatonin and pioglitazone may represent a novel strategy for the development of MSC-based therapies for patients with CKD.

Fucoidan Rescues p-Cresol-Induced Cellular Senescence in Mesenchymal Stem Cells via FAK-Akt-TWIST Axis

Mesenchymal stem cells (MSCs) are a source for cell-based therapy. Although MSCs have the potential for tissue regeneration, their therapeutic efficacy is restricted by the uremic toxin, p-cresol, in chronic kidney disease (CKD). To address this issue, we investigated the effect of fucoidan, a marine sulfated polysaccharide, on cellular senescence in MSCs. After p-cresol exposure, MSC senescence was induced, as indicated by an increase in cell size and a decrease in proliferation capacity. Treatment of senescent MSCs with fucoidan significantly reversed this cellular senescence via regulation of SMP30 and p21, and increased proliferation through the regulation of cell cycle-associated proteins (CDK2, CDK4, cyclin D1, and cyclin E). These effects were dependent on FAK-Akt-TWIST signal transduction. In particular, fucoidan promoted the expression of cellular prion protein (PrP^C), which resulted in the maintenance of cell expansion capacity in p-cresol-induced senescent MSCs. This protective effect of fucoidan on senescence-mediated inhibition of proliferation was dependent on the TWIST-PrP^C axis. In summary, this study shows that fucoidan protects against p-cresol-induced cellular senescence in MSCs through activation of the FAK-Akt-TWIST pathway and suggests that fucoidan could be used in conjunction with functional MSC-based therapies in the treatment of CKD.

A study of the initial adhesive force of cells on silk fibroin-based materials using micropipette aspiration

With the development of biomaterials, more attention is paid to the adhesion characteristics between cells and materials. It is necessary to study the adhesive force with a suitable method. Silk fibroin (SF) is widely investigated in biomedical application due to its novel biocompatibility and mechanical properties. In this article, the micropipette aspiration method and measurement pattern of uniform cells in round shape (UCR) was used to study the initial adhesive force of three types of cells on pure silk fibroin films (SFFs). We also compared the adhesive forces of modified SFFs with that of pure SFFs. The results of adhesive force in the initial adhesive stage were in concordance with the results of MTT assay and microscope observation, which were confirmed by the above three cell lines and four kinds of SFFs. The results indicated UCR was an efficient and quantitative measurement pattern in initial adhesion stage. This article also provides a useful method in identifying initial cell-materials interactions.

Low molecular weight fucoidan ameliorates hindlimb ischemic injury in type 2 diabetic rats

ETHNOPHARMACOLOGICAL RELEVANCE

Low molecular weight fucoidan (LMWF), extracted from Laminaria japonica Areschoug, is a traditional Chinese medicine, commonly used to alleviate edema, particularly for feet with numbness and pain.

AIM OF THE STUDY

Diabetic mellitus (DM) patients are at high risk of developing peripheral arterial disease (PAD). Individuals with DM and PAD co-morbidity have a much higher risk of critical limb ischemia. LMWF showed several beneficial effects, such as anti-inflammation, anti-thrombosis, and enhancing revascularization. Therefore, we hypothesized that LMWF might be beneficial to diabetes-induced PAD, and investigated the therapeutic potential of LMWF on diabetic PAD rats.

MATERIALS AND METHODS

Type 2 diabetic Goto-Kakizaki (GK) rats were made PAD by injection of sodium laurate into femoral artery. LMWF (20, 40 or 80mg/kg/day) or cilostazol (100mg/kg/day) were given to diabetic PAD rats for 4 weeks, respectively. The effects of LMWF on foot ulceration and claudication, plantar blood flow, collateral vessel formation, endothelium morphology, gastrocnemius injury, platelet aggregation, vessel vasodilation, and the expressions of inflammation factors, VEGF, eNOS, and nitric oxide were measured.

RESULTS

We found that LMWF markedly ameliorated foot ulceration and claudication, and improved the plantar perfusion by reversing hyperreactive platelet aggregation, ameliorating endothelium-dependent vasodilation and revascularization on diabetic PAD rats. In addition, upregulation of several inflammatory factors, such as ICAM-1 and IL-1β in the gastrocnemius muscles of ischemic hindlimb were suppressed by LMWF administration. And eNOS phosphorylation at Ser1177 and NO production were significantly enhanced in LMWF-treated diabetic PAD rats.

CONCLUSIONS

Taken together, our findings demonstrated that LMWF exhibits therapeutic effect on hindlimb ischemia in type 2 diabetic rats likely through ameliorating endothelium eNOS dysfunction and enhancing revascularization, thus, providing a potential supplementary non-invasive treatment for diabetes-induced PAD.

Potentiation of biological effects of mesenchymal stem cells in ischemic conditions by melatonin via upregulation of cellular prion protein expression

Mesenchymal stem cells (MSCs) are promising candidates for stem cell-based therapy in ischemic diseases. However, ischemic injury induces pathophysiological conditions, such as oxidative stress and inflammation, which diminish therapeutic efficacy of MSC-based therapy by reducing survival and functionality of transplanted MSCs. To overcome this problem, we explored the effects of melatonin on the proliferation, resistance to oxidative stress, and immunomodulatory properties of MSCs. Treatment with melatonin enhanced MSC proliferation and self-renewal via upregulation of cellular prion protein (PrP^C ) expression. Melatonin diminished the extent of MSC apoptosis in oxidative stress conditions by regulating the levels of apoptosis-associated proteins, such as BCL-2, BAX, PARP-1, and caspase-3, in a PrP^C -dependent manner. In addition, melatonin regulated the immunomodulatory effects of MSCs via the PrP^C -IDO axis. In a murine hind-limb ischemia model, melatonin-stimulated MSCs improved the blood flow perfusion, limb salvage, and vessel regeneration by lowering the extent of apoptosis of affected local cells and transplanted MSCs as well as by reducing infiltration of macrophages. These melatonin-mediated therapeutic effects were inhibited by silencing of PrP^C expression. Our findings for the first time indicate that melatonin promotes MSC functionality and enhances MSC-mediated neovascularization in ischemic tissues through the upregulation of PrP^C expression. In conclusion, melatonin-treated MSCs could provide a therapeutic strategy for vessel regeneration in ischemic disease, and the targeting of PrP^C levels may prove instrumental for MSC-based therapies.

Promising Therapeutic Strategies for Mesenchymal Stem Cell-Based Cardiovascular Regeneration: From Cell Priming to Tissue Engineering

The primary cause of death among chronic diseases worldwide is ischemic cardiovascular diseases, such as stroke and myocardial infarction. Recent evidence indicates that adult stem cell therapies involving cardiovascular regeneration represent promising strategies to treat cardiovascular diseases. Owing to their immunomodulatory properties and vascular repair capabilities, mesenchymal stem cells (MSCs) are strong candidate therapeutic stem cells for use in cardiovascular regeneration. However, major limitations must be overcome, including their very low survival rate in ischemic lesion. Various attempts have been made to improve the poor survival and longevity of engrafted MSCs. In order to develop novel therapeutic strategies, it is necessary to first identify stem cell modulators for intracellular signal triggering or niche activation. One promising therapeutic strategy is the priming of therapeutic MSCs with stem cell modulators before transplantation. Another is a tissue engineering-based therapeutic strategy involving a cell scaffold, a cell-protein-scaffold architecture made of biomaterials such as ECM or hydrogel, and cell patch- and 3D printing-based tissue engineering. This review focuses on the current clinical applications of MSCs for treating cardiovascular diseases and highlights several therapeutic strategies for promoting the therapeutic efficacy of MSCs in vitro or in vivo from cell priming to tissue engineering strategies, for use in cardiovascular regeneration.