Transplanted hUCB-MSCs migrated to the damaged area by SDF-1/CXCR4 signaling to promote functional recovery after traumatic brain injury in rats

Mesenchymal stem cells-derived IL-6 promotes invasion and metastasis of oral squamous cell carcinoma via JAK-STAT3 signalling

OBJECTIVES

Oral squamous cell carcinoma (OSCC) is often diagnosed with cervical lymph node metastasis. Mesenchymal stem cells (MSCs) and interleukin-6 (IL-6) signalling are considered to play important roles in promoting tumour malignancy. The detailed biological interaction of MSCs and IL-6 and the subsequent effect on OSCC metastasis remain largely unclear. This study aimed to determine the effects and molecular mechanism of MSCs-derived IL-6 on tumour invasion and metastasis.

SUBJECTS AND METHODS

The effects of MSC-derived IL-6 and tocilizumab on the proliferation, mobility, and epithelial-mesenchymal transition (EMT) of OSCC cells and potential pathways were detected in vitro. In addition, a murine xenograft model was generated to verify the biological mechanism in vivo.

RESULTS

The results showed that the expression of MSCs and EMT-related signals was increased in poorly differentiated OSCC tissues. MSCs released a higher level of IL-6 and promoted the proliferation, invasion, and metastasis of OSCC cells and solid neoplasms, which were activated by the downstream molecules JAK and STAT3.

CONCLUSIONS

The results indicated that MSCs-derived IL-6-promoted tumour invasion and metastasis via JAK-STAT3 signalling. Blockade of this pathway by tocilizumab may be a potential treatment to improve the prognosis and survival rate of patients with OSCC.

BMSCs attenuate radiation-induced brain injury induced hippocampal neuronal apoptosis through a PI3K/Akt/Bax/Bcl-2 signaling pathway

BACKGROUND

Bone marrow mesenchymal stem cell (BMSCs) -based therapies represent a promising treatment for neurological disorders. However, therapeutic effects and mechanisms of BMSCs transplantation for radiation-induced brain injury (RIBI) have not been fully disclosed. In this article, we explored the functions of BMSCs transplantation on RIBI and investigated the protective effects of BMSCS on hippocampal neurons in RIBI as well as the related molecular mechanisms.

MATERIALS AND METHODS

6-8 weeks-old rats were used to build a RIBI model. Rats in BMSC group were treated with a 3 × 106 BMSCs injection through the tail vein on the 1st day and 8th day after irradiation; rats in both control and RIBI groups were injected with an equivalent volume of physiological saline for comparisons. The Morris water maze was applied to detect the variations in cognitive function after RIBI. MRS was performed to test changes in NAA/Cr, indicating neuronal apoptosis after RIBI. TUNEL was conducted to detect apoptosis of rat hippocampal neurons, and HE staining was carried out to show pathological variations in the hippocampal region of rats. Protein levels of PI3K, P-PI3K, AKT, P-AKT, Bcl-2, and Bax proteins of rats in the hippocampal area were all determined by Western blot.

RESULTS

Cognitive function was reduced and hippocampal neurons underwent apoptosis in the rats of the RIBI group, and cognitive abilities, histopathological alterations, and apoptosis of hippocampal neurons were significantly improved after BMSCs treatment; the expression of PI3K, P-PI3K, AKT, P-AKT, and Bcl-2 proteins, in the hippocampal region of the rat, was up-regulated, and Bax proteins were down-regulated.

CONCLUSIONS

BMCSs can inhibit hippocampal neuronal apoptosis in RIBI, and the mechanism may be associated with the up-regulation of Bcl-2 and down-regulation of Bax by the PI3K/AKT signaling pathway.

Mesenchymal Stromal Cell-Based Targeted Therapy Pancreatic Cancer: Progress and Challenges

Pancreatic cancer is an aggressive malignancy with high mortality rates and poor prognoses. Despite rapid progress in the diagnosis and treatment of pancreatic cancer, the efficacy of current therapeutic strategies remains limited. Hence, better alternative therapeutic options for treating pancreatic cancer need to be urgently explored. Mesenchymal stromal cells (MSCs) have recently received much attention as a potential therapy for pancreatic cancer owing to their tumor-homing properties. However, the specific antitumor effect of MSCs is still controversial. To this end, we aimed to focus on the potential anti-cancer treatment prospects of the MSC-based approach and summarize current challenges in the clinical application of MSCs to treat pancreatic cancer.

C-X-C Chemokine Receptor Type 4 (CXCR-4) Functionally-Selective Allosteric Agonist ATI2341 Promotes the Recovery of Uterosacral Ligament

This study intends to assess whether CXCR4 functionally-selective allosteric agonist ATI2341 recovers uterosacral ligament. The 50 female rats were assigned into five groups including A group (normal healthy rats), B group (rats with uterine ligament injury), C group (injury rats treated with UC-MSCs cells), D group (treated with ATI2341); E group (treated with UC-MSCs cells and ATI2341) followed by analysis of uterus pathological changes by H&E staining and the expression of CD44, CD90, CXCR4, and SDF-1 by Western Blot or PT-PCR. There was regular and pyknotic fibrillar connective tissue and few small vessels in A group without infiltration of inflammatory cells. However, B group showed infiltration of inflammatory cells with few fibroblasts of fibrous tissue. The quantity of infiltration of inflammatory cells in C group and D group was less than that in B group with few visible new-born vessels. The improvement of pathological condition in uterus tissue in E group was the most among treatment groups. The number of wavy fiber was increased gradually and fibrillar connective tissue was changed into dense with elevated new-born vessels in ligament. The expression CD44, CD90, CXCR4 and SDF-1 was upregulated effectively by ATI2341. In conclusion, ATI2341 can upregulate the expression of CD44, CD90, CXCR4 and SDF-1 and promote the recovery of uterine ligament in rats, indicating that it might be a new approach for the treatment of uterine ligament.

Human Umbilical Cord-Based Therapeutics: Stem Cells and Blood Derivatives for Female Reproductive Medicine

There are several conditions that lead to female infertility, where traditional or conventional treatments have limited efficacy. In these challenging scenarios, stem cell (SC) therapies have been investigated as alternative treatment strategies. Human umbilical cord (hUC) mesenchymal stem cells (hUC-MSC), along with their secreted paracrine factors, extracts, and biomolecules, have emerged as promising therapeutic alternatives in regenerative medicine, due to their remarkable potential to promote anti-inflammatory and regenerative processes more efficiently than other autologous treatments. Similarly, hUC blood derivatives, such as platelet-rich plasma (PRP), or isolated plasma elements, such as growth factors, have also demonstrated potential. This literature review aims to summarize the recent therapeutic advances based on hUC-MSCs, hUC blood, and/or other plasma derivatives (e.g., extracellular vesicles, hUC-PRP, and growth factors) in the context of female reproductive medicine. We present an in-depth analysis of the principal molecules mediating tissue regeneration, compiling the application of these therapies in preclinical and clinical studies, within the context of the human reproductive tract. Despite the recent advances in bioengineering strategies that sustain delivery and amplify the scope of the therapeutic benefits, further clinical trials are required prior to the wide implementation of these alternative therapies in reproductive medicine.

Effects of Low-Intensity Pulsed Ultrasound on the Migration and Homing of Human Amnion-Derived Mesenchymal Stem Cells to Ovaries in Rats With Premature Ovarian Insufficiency

Premature ovarian insufficiency (POI) can cause multiple sequelae and is currently incurable. Mesenchymal stem cell (MSC) transplantation might provide an effective treatment method for POI. However, the clinical application of systemic MSC transplantation is limited by the low efficiency of cell homing to target tissue in vivo, including systemic MSC transplantation for POI treatment. Thus, exploration of methods to promote MSC homing is necessary. This study was to investigate the effects of low-intensity pulsed ultrasound (LIPUS) on the migration and homing of transplanted human amnion–derived MSCs (hAD-MSCs) to ovaries in rats with chemotherapy-induced POI. For LIPUS treatment, hAD-MSCs were exposed to LIPUS or sham irradiation. Chemokine receptor expressions in hAD-MSCs were detected by polymerase chain reaction (PCR), Western blot, and immunofluorescence assays. hAD-MSC migration was detected by wound healing and transwell migration assays. Cyclophosphamide-induced POI rat models were established to evaluate the effects of LIPUS on the homing of systemically transplanted hAD-MSCs to chemotherapy-induced POI ovaries in vivo. We found that hAD-MSCs expressed chemokine receptors. The LIPUS promoted the expression of chemokine receptors, especially CXCR4, in hAD-MSCs. SDF-1 induced hAD-MSC migration. The LIPUS promoted hAD-MSC migration induced by SDF-1 through SDF-1/CXCR4 axis. SDF-1 levels significantly increased in ovaries induced by chemotherapy in POI rats. Pretreating hAD-MSCs with LIPUS increased the number of hAD-MSCs homing to ovaries in rats with chemotherapy-induced POI to some extent. However, the difference was not significant. Both hAD-MSC and LIPUS-pretreated hAD-MSC transplantation reduced ovarian injuries and improved ovarian function in rats with chemotherapy-induced POI. CXCR4 antagonist significantly reduced the number of hAD-MSCs- and LIPUS-pretreated hAD-MSCs homing to POI ovaries, and further reduced their efficacy in POI treatment. According to these findings, pretreating MSCs with LIPUS before transplantation might provide a novel, convenient, and safe technique to explore for improving the homing of systemically transplanted MSCs to target tissue.

Down-Regulation of CXCR4 in Mesenchymal Stem Cells by Septic Serum

Background

Sepsis is one of the main concerns of health and one of the leading causes of death in hospitals. It is essential to manage sepsis in hospitalized patients. In recent years, cell therapy has been considered as a new approach to treat sepsis. This study evaluated the effect of CXCR4 as one of the main proteins involved in the homing of mesenchymal stem cells in the sepsis serum in mice model.

Methods

Mouse sepsis model was induced by injection of E.coli and biochemical analyses was done to confirm the organ failure. Mesenchymal stem cells (MSCs) derived from bone marrow were separated into sepsis and control groups. In the sepsis serum group, MSCs were treated with sepsis serum at two time points: 24 and 48 h. Quantitative RT-PCR and flow cytometry were performed to determine the mRNA expression of CXCR4 in sepsis serum group compared to control group. Also, a migration assay was done to assess the migration capacity of bone marrow MSCs during inflammation and treatment in sepsis.

Results

Our result showed that treatment with sepsis serum can control migration by decrease in CXCR4 level (P ≤ 0.05) compared to control group. Moreover it was also reported that sepsis serum decreased mRNA expression of CXCR4 in MScs.

Conclusions

In our study, MSCs treated with septic serum were no longer able to migrate . Probably many variables such as source, dose, injection time, and injection route of MSCs after sepsis induction in the animal models are key factors for successful cell therapy.

Mesenchymal stem cells (MSCs) in Leber's hereditary optic neuropathy (LHON): a potential therapeutic approach for future

BACKGROUND

Optic neuropathy has become a new typical syndromic multi-system disease that leads to optic atrophy. This review discusses potential treatments and advances of Leber's hereditary optic neuropathy (LHON), a sporadic genetic disorder. LHON is caused due to slight mutations in mitochondria leading to mitochondrial dysfunction, causing vision loss. There are no current significant treatments that have been proven to work for LHON.

METHODS

However, extensive review was carried out on capable studies that have shown potential treatment sensory systems and are being evaluated currently. Some of these studies are in clinical trials, whereas other ones are still being planned. Here, we focus more on treatment based on mesenchymal stem cells-mediated mitochondrial transfer via various techniques. We discuss different mitochondrial transfer modes and possible ways to understand the mitochondria transfer technique's phenotypic characteristics.

CONCLUSION

It is clearly understood that transfer of healthy mitochondria from MSC to target cell would regulate the range of reactive oxygen species and ATP'S, which are majorly responsible for mutation upon irregulating. Therefore, mitochondrial transfer is suggested and discussed in this review with various aspects. The graphical abstract represents different means of mitochondrial transport like (a) Tunnelling nanotubules, (b) Extracellular vesicles, (c) Cell fusion and (d) Gap junctions. In (a) Tunnelling nanotubules, the signalling pathways TNF- α/TNF αip2 and NFkB/TNF αep2 are responsible for forming tunnels. Also, Miro protein acts as cargo for the transport of mitochondria with myosin's help in the presence of RhoGTPases [35]. In (b) Extracellular vesicles, the RhoA ARF6 contributes to Actin/Cytoskeletal rearrangement leading to the shedding of microvesicles. Coming to (c) Cell fusion when there is a high amount of ATP, the cells tend to fuse when in close proximity leading to the transfer of mitochondria via EFF-1/HAP2 [48]. In (d) Gap Junctions, Connexin43 is responsible for the intracellular channel in the presence of more ATP [86].

Ginsenoside Rb1 Modulates the Migration of Bone-Derived Mesenchymal Stem Cells through the SDF-1/CXCR4 Axis and PI3K/Akt Pathway

Background and Objectives. Bone mesenchymal stem cells (BMSCs) play a vital role in skin wound healing and skin regeneration through proliferation, migration, and paracrine interactions. A previous study indicated that ginsenoside Rb1 acted as a vital antidotal component which antagonized the oxidative stem cell. However, the effect and mechanism of ginsenoside Rb1-mediated BMSC migration remained unknown. Methods. Wound-healing assay and Transwell assay were utilized to evaluate the effect of ginsenoside Rb1 on the migration of BMSCs. RT-PCR and Western blotting were performed to evaluate the expression of stromal-derived factor 1 (SDF-1), C-X-C chemokine receptor type 4 (CXCR4), phosphatidylinositol 3-kinase (PI3K), and protein kinase B (PKB; AKT). Results. Ginsenoside Rb1 significantly enhanced the migration of BMSCs through the activation of SDF-1, CXCR4, p-PI3K/PI3K, and p-Akt/Akt relative expression. Furthermore, this stimulus was blocked by the pretreatment with AMD3100 and LY294002. Conclusions. Ginsenoside Rb1 facilitated the migration of BMSCs through the activation of the SDF-1/CXCR4 axis and PI3K/Akt pathway.

Important role of the SDF-1/CXCR4 axis in the homing of systemically transplanted human amnion-derived mesenchymal stem cells (hAD-MSCs) to ovaries in rats with chemotherapy-induced premature ovarian insufficiency (POI)

Background

Chemotherapy can induce premature ovarian insufficiency (POI). POI causes multiple sequelae and is currently incurable. As shown in our previous studies, systemically transplanted human amnion-derived mesenchymal stem cells (hAD-MSCs) home to ovaries with chemotherapy-induced POI and subsequently reduce ovarian injury and improve ovarian function in rats with POI. However, the cellular mechanisms that direct the migration and homing of hAD-MSCs to ovaries with chemotherapy-induced POI are incompletely understood. This study investigated the role of the SDF-1/CXCR4 axis in the migration and homing of systemically transplanted hAD-MSCs to ovaries with chemotherapy-induced POI and its relevant downstream signalling pathways.

Methods

CXCR4 expression in hAD-MSCs was assessed using Western blotting and immunofluorescence staining. hAD-MSC migration was tested using Transwell migration assays. SDF-1 levels were detected using ELISA. Seventy-two female SD rats were randomly divided into the control, POI, hAD-MSCs and hAD-MSCs + AMD3100 groups. Cyclophosphamide was used to establish rat POI models. For inhibitor treatment, hAD-MSCs were pretreated with AMD3100 before transplantation. PKH26-labeled hAD-MSCs were injected into the tail vein of POI rats 24 h after chemotherapy. After hAD-MSC transplantation, the homing of hAD-MSCs to ovaries and ovarian function and pathological changes were examined. We further investigated the molecular mechanisms by detecting the PI3K/Akt and ERK1/2 signalling pathways.

Results

hAD-MSCs expressed CXCR4. SDF-1 induced hAD-MSC migration in vitro. SDF-1 levels in ovaries and serum were significantly increased in rats with chemotherapy-induced POI, and ovaries with POI induced the homing of hAD-MSCs expressing CXCR4. Blocking the SDF-1/CXCR4 axis with AMD3100 significantly reduced the number of hAD-MSCs homing to ovaries with POI and further reduced their efficacy in POI treatment. The binding of SDF-1 to CXCR4 activated the PI3K/Akt signalling pathway, and LY294002 significantly inhibited hAD-MSC migration induced by SDF-1 in vitro. Moreover, inhibition of the PI3K/Akt signalling pathway significantly reduced the number of systemically transplanted hAD-MSCs homing to chemotherapy-induced ovaries in rats with POI.

Conclusions

SDF-1/CXCR4 axis partially mediates the migration and homing of systemically transplanted hAD-MSCs to the ovaries of rats with chemotherapy-induced POI, and the PI3K/Akt signalling pathway might be involved in the migration and homing of hAD-MSCs mediated by the SDF-1/CXCR4 axis.

Human Umbilical Cord Mesenchymal Stem Cells Improve the Necrosis and Osteocyte Apoptosis in Glucocorticoid-Induced Osteonecrosis of the Femoral Head Model through Reducing the Macrophage Polarization

Background and Objectives

Apoptosis is an outstanding determinant of glucocorticoid (GC)-induced osteonecrosis of the femoral head (ONFH). Human umbilical cord mesenchymal stem cells (hUC-MSCs) have been demonstrated to be associated with apoptosis in diseases models. However, the role of hUC-MSCs in GC-induced ONFH via regulating apoptosis still needs further study.

Methods and Results

In the present study, a GC-induced ONFH model was built in vivo through a consecutive injection with lipopolysaccharide (LPS) and methylprednisolone. The necrosis and apoptosis of the femoral head was evaluated by histological and Terminal-deoxynucleoitidyl Transferase Mediated Nick End Labeling (TUNEL) assay. The level of collagen and TRAP positive cells were determined by Masson and TRAP staining, respectively. M1 macrophage polarization was assessed using immunofluorescence assay. The level of proinflammatory cytokines including tumor necrosis factor (TNF)‐α, Interleukin (IL)‐1β and IL-6 of femoral head was determined by enzyme-linked immunosorbent assay (ELISA) kits. The protein expression of AKT, mTOR, p-AKT and p-mTOR was detected using western blot assay. The results showed that hUC-MSCs treatment prominently promoted the GC-induced the decrease of the collagen level and the increase of TRAP positive cells. Besides, hUC-MSCs treatment decreased necrosis and apoptosis, macrophage polarization, the level of TNF‐α, IL‐1β and IL-6, the protein expression of p-AKT and p-mTOR, and the radio of p-AKT to AKT and p-mTOR to mTOR of femoral head in vivo.

Conclusions

Therefore, the present study revealed that hUC-MSCs improved the necrosis and osteocyte apoptosis in GC-induced ONFH model through reducing the macrophage polarization, which was associated with the inhibition of AKT/mTOR signaling pathway.

Phenotypic and Functional Responses of Human Decidua Basalis Mesenchymal Stem/Stromal Cells to Lipopolysaccharide of Gram-Negative Bacteria

Introduction

Human decidua basalis mesenchymal stem cells (DBMSCs) are potential therapeutics for the medication to cure inflammatory diseases, like atherosclerosis. The current study investigates the capacity of DBMSCs to stay alive and function in a harmful inflammatory environment induced by high levels of lipopolysaccharide (LPS).

Methods

DBMSCs were exposed to different levels of LPS, and their viability and functional responses (proliferation, adhesion, and migration) were examined. Furthermore, DBMSCs’ expression of 84 genes associated with their functional activities in the presence of LPS was investigated.

Results

Results indicated that LPS had no significant effect on DBMSCs’ adhesion, migration, and proliferation (24 h and 72 h) (p > 0.05). However, DBMSCs’ proliferation was significantly reduced at 10 µg/mL of LPS at 48 h (p < 0.05). In addition, inflammatory cytokines and receptors related to adhesion, proliferation, migration, and differentiation were significantly overexpressed when DBMSCs were treated with 10 µg/mL of LPS (p < 0.05).

Conclusion

These results indicated that DBMSCs maintained their functional activities (proliferation, adhesion, and migration) in the presence of LPS as there was no variation between the treated DBMSCs and the control group. This study will lay the foundation for future preclinical and clinical studies to confirm the appropriateness of DBMSCs as a potential medication to cure inflammatory diseases, like atherosclerosis.

Systematic review and meta-analysis of preclinical studies testing mesenchymal stromal cells for traumatic brain injury

Mesenchymal stromal cells (MSCs) are widely used in preclinical models of traumatic brain injury (TBI). Results are promising in terms of neurological improvement but are hampered by wide variability in treatment responses. We made a systematic review and meta-analysis: (1) to assess the quality of evidence for MSC treatment in TBI rodent models; (2) to determine the effect size of MSCs on sensorimotor function, cognitive function, and anatomical damage; (3) to identify MSC-related and protocol-related variables associated with greater efficacy; (4) to understand whether MSC manipulations boost therapeutic efficacy. The meta-analysis included 80 studies. After TBI, MSCs improved sensorimotor and cognitive deficits and reduced anatomical damage. Stratified meta-analysis on sensorimotor outcome showed similar efficacy for different MSC sources and for syngeneic or xenogenic transplants. Efficacy was greater when MSCs were delivered in the first-week post-injury, and when implanted directly into the lesion cavity. The greatest effect size was for cells embedded in matrices or for MSC-derivatives. MSC therapy is effective in preclinical TBI models, improving sensorimotor, cognitive, and anatomical outcomes, with large effect sizes. These findings support clinical studies in TBI.

Inflammatory Modulation of Polyethylene Glycol-AuNP for Regulation of the Neural Differentiation Capacity of Mesenchymal Stem Cells

A nanocomposite composed of polyethylene glycol (PEG) incorporated with various concentrations (~17.4, ~43.5, ~174 ppm) of gold nanoparticles (Au) was created to investigate its biocompatibility and biological performance in vitro and in vivo. First, surface topography and chemical composition was determined through UV-visible spectroscopy (UV-Vis), Fourier-transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), scanning electron microscopy (SEM), free radical scavenging ability, and water contact angle measurement. Additionally, the diameters of the PEG-Au nanocomposites were also evaluated through dynamic light scattering (DLS) assay. According to the results, PEG containing 43.5 ppm of Au demonstrated superior biocompatibility and biological properties for mesenchymal stem cells (MSCs), as well as superior osteogenic differentiation, adipocyte differentiation, and, particularly, neuronal differentiation. Indeed, PEG-Au 43.5 ppm induced better cell adhesion, proliferation and migration in MSCs. The higher expression of the SDF-1α/CXCR4 axis may be associated with MMPs activation and may have also promoted the differentiation capacity of MSCs. Moreover, it also prevented MSCs from apoptosis and inhibited macrophage and platelet activation, as well as reactive oxygen species (ROS) generation. Furthermore, the anti-inflammatory, biocompatibility, and endothelialization capacity of PEG-Au was measured in a rat model. After implanting the nanocomposites into rats subcutaneously for 4 weeks, PEG-Au 43.5 ppm was able to enhance the anti-immune response through inhibiting CD86 expression (M1 polarization), while also reducing leukocyte infiltration (CD45). Moreover, PEG-Au 43.5 ppm facilitated CD31 expression and anti-fibrosis ability. Above all, the PEG-Au nanocomposite was evidenced to strengthen the differentiation of MSCs into various cells, including fat, vessel, and bone tissue and, particularly, nerve cells. This research has elucidated that PEG combined with the appropriate amount of Au nanoparticles could become a potential biomaterial able to cooperate with MSCs for tissue regeneration engineering.

Involvement of various chemokine/chemokine receptor axes in trafficking and oriented locomotion of mesenchymal stem cells in multiple sclerosis patients

Multiple sclerosis (MS) is a specific type of chronic immune-mediated disease in which the immune responses are almost run against the central nervous system (CNS). Despite intensive research, a known treatment for MS disease yet to be introduced. Thus, the development of novel and safe medications needs to be considered for the disease management. Application of mesenchymal stem cells (MSCs) as an emerging approach was recruited forthe treatment of MS. MSCs have several sources and they can be derived from the umbilical cord, adipose tissue, and bone marrow. Chemokines are low molecular weight proteins that their functional activities are achieved by binding to the cell surface G protein-coupled receptors (GPCRs). Chemokine and chemokine receptors are of the most important and effective molecules in MSC trafficking within the different tissues in hemostatic and non-hemostatic circumstances. Chemokine/chemokine receptor axes play a pivotal role in the recruitment and oriented trafficking of immune cells both towards and within the CNS and it appears that chemokine/chemokine receptor signaling may be the most important leading mechanisms in the pathogenesis of MS. In this article, we hypothesized that the chemokine/chemokine receptor axes network have crucial and efficacious impacts on behavior of the MSCs, nonetheless, the exact responsibility of these axes on the targeted tropism of MSCs to the CNS of MS patients yet remained to be fully elucidated. Therefore, we reviewed the ability of MSCs to migrate and home into the CNS of MS patients via expression of various chemokine receptors in response to chemokines expressed by cells of CNS tissue, to provide a great source of knowledge.

Sodium alginate/collagen/stromal cell-derived factor-1 neural scaffold loaded with BMSCs promotes neurological function recovery after traumatic brain injury

Stem cell therapy is promising for neural repair in devastating traumatic brain injury (TBI). However, the low survival and differentiation rates of transplanted stem cells are main obstacles to efficient stem cell therapy in TBI. Stromal cell-derived factor-1 (SDF-1) and its receptor CXCR4 are key factors that regulate the survival, recruitment, and differentiation of stem cells. Herein, we synthesized a sodium alginate (SA)/collagen type I (Col)/SDF-1 hydrogel and investigated whether the SA/Col/SDF-1 hydrogel loaded with bone marrow-derived mesenchymal stem cells (BMSCs) had therapeutic effects on a TBI model. Our results showed that the SA/Col/SDF-1 scaffold could stably release SDF-1 and provide biocompatible and biodegradable microenvironment for the survival, migration, and neuronal differentiation of BMSCs in vitro. In a rat model of TBI, the SA/Col/SDF-1 hydrogel loaded with BMSCs significantly ameliorated motor and cognition dysfunction and relieved anxiety and depressive-like behaviors. In addition, the BMSCs/SA/Col/SDF-1 scaffold reduced brain lesions and neuronal cell death and mitigated neuroinflammation. Further studies demonstrated that the BMSCs/SA/Col/SDF-1 hydrogel promoted the migration of BMSCs in the lesions and partly enhanced neurogenesis by activating the SDF-1/CXCR4-mediated FAK/PI3K/AKT pathway. Taken together, our results indicate that the SA/Col/SDF-1 scaffold loaded with BMSCs exerts neuroreparative effects in a TBI rat model, and thus, it may serve as an alternative neural regeneration scaffold for brain injury repair. STATEMENT OF SIGNIFICANCE: Hydrogel facilitates the biological behaviors of transplanted stem cells for tissue regeneration. In this study, we synthesized sodium alginate (SA)/collagen type I (Col)/ scaffold to simultaneously deliver stromal cell derived factor-1 (SDF-1) and bone marrow mesenchymal stem cells (BMSCs) in a rat model of traumatic brain injury (TBI). We found that the SA/Col/SDF-1 hydrogel could continuously release SDF-1 and was conducive to the survival, migration and neuronal differentiation of BMSCs in vitro. In addition, the SA/Col/SDF-1 hydrogel loaded with BMSCs significantly ameliorated neurological deficits, mitigated neuroinflammation, promoted the recruitment of BMSCs and enhanced neurogenesis in TBI partly by activating the SDF-1/CXCR4-mediated FAK/PI3K/AKT pathway. Our results may serve as an alternative neural regeneration strategy for brain injury.

SDF-1/CXCR4 Augments the Therapeutic Effect of Bone Marrow Mesenchymal Stem Cells in the Treatment of Lipopolysaccharide-Induced Liver Injury by Promoting Their Migration Through PI3K/Akt Signaling Pathway

Mesenchymal stem cells (MSCs) are thought to have great potential in the therapy of acute liver injury. It is possible that these cells may be regulated by the stromal cell-derived factor-1 (SDF-1)/CXC chemokine receptor-4 (CXCR4) signaling axis, which has been shown to promote stem cells migration in the inflammation-associated diseases. However, the effects of SDF-1/CXCR4 axis on the MSCs-transplantation-based treatment for acute liver injury and the underlying mechanisms are largely unknown. In this study, we sought to determine whether SDF-1/CXCR4 would augment the therapeutic effect of bone marrow mesenchymal stem cells (BMSCs) by promoting their migration, which may result from activating the phosphoinositide 3-kinase (PI3K)/Akt signaling pathway, in a rat acute liver injury model induced by lipopolysaccharide (LPS). We found that BMSCs transplantation markedly attenuated liver injury and improved the survival of LPS-treated rats. Of interest, overexpression of CXCR4 in BMSCs could substantially promote their migration both in vitro and in vivo, and result in even better therapeutic effects. This might be attributed to the activation of PI3K/Akt signaling pathway in BMSCs that is downstream of CXCR4, as demonstrated by the use of the CXCR4 antagonist AMD3100 and PI3K pathway inhibitor LY294002 assays in vitro and in vivo. Together, our results unraveled a novel molecular mechanism for the therapeutic effect of BMSCs for the treatment of acute liver injury, which may shed a new light on the clinical application of BMSCs for acute liver failure.

Dedifferentiated human umbilical cord mesenchymal stem cell reprogramming of endogenous hSDF-1α expression participates in neural restoration in hypoxic-ischemic brain damage rats

The transplantation of human umbilical cord mesenchymal stem cells (hUC-MSCs) can promote hypoxic-ischemic brain damage (HIBD) nerve repair, but finding suitable seed cells to optimize transplantation and improve treatment efficiency is an urgent problem to be solved. In this study, we induced hUC-MSCs into dedifferentiated hUC-MSCs (De-hUC-MSCs), and the morphology, stem cell surface markers, proliferation and tri-directional differentiation ability of the De-hUC-MSCs and hUC-MSCs were detected. A whole-gene chip was utilized for genome cluster, gene ontology and KEGG pathway analyses of differentially expressed genes. De-hUC-MSCs were transplanted into HIBD rats, and behavioral experiments and immunofluorescence assays were used to assess the therapeutic effect. A lentivirus vector for human stromal cell-derived factor-1 (hSDF-1α) was constructed, and the role of hSDF-1α in the neuroprotective effect and mechanism of De-hUC-MSCs was verified. De-hUC-MSCs displayed similar cell morphology, stem cell surface marker expression, cell proliferation and even three-dimensional differentiation ability as hUC-MSCs but exhibited greater treatment potential in vivo. The reprogramming mechanism of hSDF-1α participated in the dedifferentiation process. By successfully constructing a stable hSDF-1α cell line, we found that De-hUC-MSCs might participate in nerve repair through the hSDF-1α/CXCR4/PI3K/Akt pathway. De-hUC-MSCs reprogramming of endogenous hSDF-1α expression may mediate the hSDF-1α/CXCR4/PI3K/Akt pathway involved in nerve repair in HIBD rats.

CXCR7, CXCR4, and Their Ligand Expression Profile in Traumatic Brain Injury

OBJECTIVE

Traumatic brain injury (TBI) is a health problem worldwide, and therapeutic strategies to enhance brain tissue repair to lessen neurologic sequels are imperative. We aimed to analyze the impact of the inflammatory process in TBI through CXCR4 and CXCR7 chemokine receptors and their ligands' CXCL11 and CXCL12 expression profile in search for potential new druggable targets.

METHODS

Twelve pericontusional tissues from severe TBI patients submitted to surgical treatment, and 20 control brain tissues from normal autopsy were analyzed for expression profile by real-time quantitative-polymerase chain reaction. CXCR7 and CXCR4 protein expressions were analyzed by immunohistochemistry. The findings were correlated with the clinical evolution.

RESULTS

Increased gene expression of both receptors and their ligands was observed in TBI compared with controls, presenting high sensitivity and specificity to differentiate TBI from normal control (area under the curve ranging from 0.85 to 0.98, P < 0.001). In particular, CXCR7 expression highly correlated with CXCR4 and both ligands' expressions in TBI. Higher immunoreactions for CXCR7 and CXCR4 were identified in neurons and endothelial cells of TBI samples compared with controls. The patients presenting upregulated chemokine expression levels showed a trend toward favorable clinical evolution at up to 6 months of follow-up.

CONCLUSIONS

The neuroprotective trend of CXCR4, CXCR7, CXCL11, and CXCL12 in TBI observed in this initial analysis warrants further studies with more patients, analyzing the involved signaling pathways for the development of new therapeutic strategies for TBI.

Quantification of the CM-Dil-labeled human umbilical cord mesenchymal stem cells migrated to the dual injured uterus in SD rat

Background

Human umbilical cord mesenchymal stem cell (hUC-MSC) therapy is considered as a promising approach in the treatment of intrauterine adhesions (IUAs). Considerable researches have already detected hUC-MSCs by diverse methods. This paper aims at exploring the quantitative distribution of CM-Dil-labeled hUC-MSCs in different regions of the uterus tissue of the dual injury-induced IUAs in rats and the underlying mechanism of restoration of fertility after implantation of hUC-MSCs in the IUA model.

Methods

In this study, we investigated the quantification of the CM-Dil-labeled hUC-MSCs migrated to the dual injured uterus in Sprague Dawley rats. Additionally, we investigated the differentiation of CM-Dil-labeled hUC-MSCs. The differentiation potential of epithelial cells, vascular endothelial cells, and estrogen receptor (ER) cells were assessed by an immunofluorescence method using CK7, CD31, and ERα. The therapeutic impact of hUC-MSCs in the IUA model was assessed by hematoxylin and eosin, Masson, immunohistochemistry staining, and reproductive function test. Finally, the expression of TGF-β1/Smad3 pathway in uterine tissues was determined by qRT-PCR and Western blotting.

Results

The CM-Dil-labeled cells in the stroma region were significantly higher than those in the superficial myometrium (SM) (71.67 ± 7.98 vs. 60.92 ± 3.96, p = 0.005), in the seroma (71.67 ± 7.98 vs. 23.67 ± 8.08, p = 0.000) and in the epithelium (71.67 ± 7.98 vs. 4.17 ± 1.19, p = 0.000). From the 2nd week of treatment, hUC-MSCs began to differentiate into epithelial cells, vascular endothelial cells, and ER cells. The therapeutic group treated with hUC-MSCs exhibited a significant decrease in fibrosis (TGF-β1/Smad3) as well as a significant increase in vascularization (CD31) compared with the untreated rats.

Conclusion

Our findings suggested that the distribution of the migrated hUC-MSCs in different regions of the uterine tissue was unequal. Most cells were in the stroma and less were in the epithelium of endometrium and gland. Injected hUC-MSCs had a capacity to differentiate into epithelial cells, vascular endothelial cells, and ER cells; increase blood supply; inhibit fibration; and then restore the fertility of the IUA model.

HIF-1α/SDF-1/CXCR4 axis reduces neuronal apoptosis via enhancing the bone marrow-derived mesenchymal stromal cell migration in rats with traumatic brain injury

Mesenchymal stromal injection is a promising therapy for traumatic brain injury (TBI). The aim of this study was to explore the effects of the HIF-1α/SDF-1/CXCR4 axis on neuron repair in TBI rats through improving the bone marrow-derived mesenchymalstromal cells (BMSCs) migration. TBI rat models were established. The rats were treated with exogenous SDF-1, and then the neuronal apoptosis in TBI rats was measured. BMSCs from rats were collected, and the roles of NF-κB p65 expression in nuclei, overexpression of SDF-1 and HIF-1α, as well as downregulation of CXCR4 in BMSC migration were identified. HIF-1α- and SDF-1- treated BMSCs were transplanted into TBI rats, after which the neuronal apoptosis and activity of the HIF-1α/SDF-1/CXCR4 axis were detected. Consequently, we found SDF-1 elevated the HIF-1α/SDF-1/CXCR4 activity and presented protective roles in TBI rat hippocampal neurons with reduced neuronal apoptosis. SDF-1 promoted BMSC migration in vitro, and co-effects of SDF-1 and HIF-1α showed strong promotion, while CXCR4 inhibition suppressed BMSC migration. BMSC transplantation activated the HIF-1α/SDF-1/CXCR4 axis and reduced neuronal apoptosis in TBI rats. To conclude, our study demonstrated that the HIF-1α/SDF-1/CXCR4 axis could enhance BMSC migration and alleviate neuronal damage and apoptosis in TBI rats. This study provided novel options for TBI therapy.

Advances in CXCR7 Modulators

CXC chemokine receptor 7 (CXCR7) is a G-protein-coupled receptor that signals through the β-arrestin pathway. Its ligands include interferon-inducible T cell α chemoattractant (CXCL11) and stromal cell-derived factor-1 (CXCL12). It interacts with CXCR4, and the two are associated with various cancers, as well as other disease states such as coronary artery disease, stroke, inflammation and human immunodeficiency virus (HIV). Antibodies and small interfering RNA (siRNA) have shown the utility of antagonists of CXCR7 in these disease states. Although some small molecules were initially reported as antagonists due to their displayed activity, many function as agonists while still producing the desired pharmacologic effects. A potential reason for this contradiction is that effects may be due to elevated extracellular CXCL12 levels.

Therapeutic Potential of Mesenchymal Stem Cells for Cancer Therapy

Mesenchymal stem cells (MSCs) are among the most frequently used cell type for regenerative medicine. A large number of studies have shown the beneficial effects of MSC-based therapies to treat different pathologies, including neurological disorders, cardiac ischemia, diabetes, and bone and cartilage diseases. However, the therapeutic potential of MSCs in cancer is still controversial. While some studies indicate that MSCs may contribute to cancer pathogenesis, emerging data reported the suppressive effects of MSCs on cancer cells. Because of this reality, a sustained effort to understand when MSCs promote or suppress tumor development is needed before planning a MSC-based therapy for cancer. Herein, we provide an overview on the therapeutic application of MSCs for regenerative medicine and the processes that orchestrates tissue repair, with a special emphasis placed on cancer, including central nervous system tumors. Furthermore, we will discuss the current evidence regarding the double-edged sword of MSCs in oncological treatment and the latest advances in MSC-based anti-cancer agent delivery systems.

Mesenchymal stromal cell secretome as a therapeutic strategy for traumatic brain injury

Traumatic brain injury (TBI) is a global health problem that is a common cause of disability and mortality. Despite the availability of many treatment options, none is capable of restoring functional and structural recovery of the damaged brain. Both the results of preclinical and clinical studies suggest the use of mesenchymal stromal cells (MSCs) as a therapeutic strategy for structural and functional recovery in TBI. However, recent evidence shows that the neuroprotective potential of MSCs is due to multiple secretions of bioactive molecules that modulate tissue microenvironment for tissue repair and regeneration. The results of preclinical studies indicate the therapeutic benefits of MSC secretome in TBI. Soluble bioactive molecules and extracellular vesicles are the various factors secreted by MSCs that can induce neurogenesis, angiogenesis, neovascularization, and anti-inflammatory activities. This review highlights the neuroprotective effect of MSC secretome for the treatment of TBI. In addition, the possible challenges of secretome as biotherapeutics are identified and how some of the issues raised could be overcome for effective clinical application are also discussed.

Hypoxic preconditioning improves the survival and neural effects of transplanted mesenchymal stem cells via CXCL12/CXCR4 signalling in a rat model of cerebral infarction

The treatment of neural deficiency after cerebral infarction is challenging, with limited therapeutic options. The transplantation of mesenchymal stem cells (MSCs) to the ischemic penumbra is a potential therapeutic approach. In the present study, a cerebral infarction model was generated by performing middle cerebral artery occlusion (MCAO) in SD rats. The expression of CXCR4 increased, and the number of MSCs migrating to the peri-infarct area was higher in rats transplanted with preconditioned MSCs than in rats transplanted with untreated MSCs. The rate of apoptosis, as evaluated by TUNEL staining and immunoblotting assays, was reduced in rats receiving preconditioned MSCs. A significant amelioration of neural regeneration and improved neurological function were observed in rats injected with preconditioned MSCs compared with those injected with untreated MSCs. However, the application of an siRNA targeting CXCL12 significantly inhibited the protective role of preconditioned MSCs against apoptosis and promoted the migration of MSCs to the ischemic area, leading to impaired neuronal regeneration and limited recovery of neuronal function. Hypoxic preconditioning of MSCs prior to transplantation suppressed apoptosis and increased their migration abilities, leading to the promotion of neuronal regeneration and improvement in neural function after transplantation. This preconditioning strategy may be considered as a potential approach for the modification of MSCs prior to cell transplantation therapy in patients with cerebral infarction. SIGNIFICANCE OF THE STUDY: We found that hypoxic preconditioning of MSCs improved their ability to promote neuronal regeneration and the recovery of neuronal function. Moreover, we showed that CXCR4 inhibited apoptosis, improved cell homing, and promoted neuronal differentiation, without influencing angiogenesis. Our study provides a relatively safe preconditioning method for potential use for cell transplantation therapy in ischemic cerebral infarction. The results presented here will facilitate the development of novel strategies and techniques to improve the tolerance and migration ability of transplanted cells for the treatment of cerebral infarction sequelae.

Placenta-Derived Cells for Acute Brain Injury

Acute brain injury resulting from ischemic/hemorrhagic or traumatic damage is one of the leading causes of mortality and disability worldwide and is a significant burden to society. Neuroprotective options to counteract brain damage are very limited in stroke and traumatic brain injury (TBI). Given the multifaceted nature of acute brain injury and damage progression, several therapeutic targets may need to be addressed simultaneously to interfere with the evolution of the injury and improve the patient’s outcome. Stem cells are ideal candidates since they act on various mechanisms of protection and repair, improving structural and functional outcomes after experimental stroke or TBI. Stem cells isolated from placenta offer advantages due to their early embryonic origin, ease of procurement, and ethical acceptance. We analyzed the evidence for the beneficial effects of placenta-derived stem cells in acute brain injury, with the focus on experimental studies of TBI and stroke, the engineering strategies pursued to foster cell potential, and characterization of the bioactive molecules secreted by placental cells, known as their secretome, as an alternative cell-free strategy. Results from the clinical application of placenta-derived stem cells for acute brain injury and ongoing clinical trials are summarily discussed.

Danhong Injection Enhances the Therapeutic Efficacy of Mesenchymal Stem Cells in Myocardial Infarction by Promoting Angiogenesis

Stem cell-based therapies have the potential to dramatically transform the treatment and prognosis of myocardial infarction (MI), and mesenchymal stem cells (MSCs) have been suggested as a promising cell population to ameliorate the heart remodeling in post-MI. However, poor implantation and survival in ischemic myocardium restrict its efficacy and application. In this study, we sought to use the unique mode of action of Chinese medicine to improve this situation. Surrounding the myocardial infarct area, we performed a multi-point MSC transplantation and administered in conjunction with Danhong injection, which is mainly used for the treatment of MI. Our results showed that the MSC survival rate and cardiac function were improved significantly through the small animal imaging system and echocardiography, respectively. Moreover, histological analysis showed that MSC combined with DHI intervention significantly reduced myocardial infarct size in myocardial infarcted mice and significantly increased MSC resident. To investigate the mechanism of DHI promoting MSC survival and cell migration, PCR and WB experiments were performed. Our results showed that DHI could promote the expression of CXC chemokine receptor 4 in MSC and enhance the expression of stromal cell–derived factor-1 in myocardium, and this effect can be inhibited by AMD3100 (an SDF1/CXCR4 antagonist). Additionally, MSC in combination with DHI interfered with MI in mice and this signifies that when combined, the duo could the expression of vascular endothelial growth factor (VEGF) in the marginal zone of infarction compared with when either MSC or DHI are used individually. Based on these results, we conclude that DHI enhances the residence of MSCs in cardiac tissue by modulating the SDF1/CXCR4 signaling pathway. These findings have important therapeutic implications for Chinese medicine-assisted cell-based therapy strategies.

Augmented migration of mesenchymal stem cells correlates with the subsidiary CXCR4 variant

Use of mesenchymal stem cells (MSCs) has been introduced as a promising tool, for structural and functional recovery of damaged tissues/organs. Studies have indicated that interactions between chemokine receptors and their ligands have a critical role in homing of MSCs to the site of injury. Although CXCR4 variants have been characterized, the exact role of each transcript in homing has remained unclear. In this study, cells were pretreated with various hypoxia-mimicking compounds (valproic acid, cobalt-chloride, and deferoxamine mesylate). Results indicated that both variants of CXCR4 were overexpressed after 24 hours of treatments and their expression could cooperatively induce and promote the cell migration. Moreover, deferoxamine mesylate was more effective in overexpression of variant A (lo), which resulted in higher level of CXCR4 protein and the highest rate of migration of the cells. In conclusion, our findings may have important potential implications in clinical applications, reinforcing the concept that manipulating the expression of specific CXCR4 variants may increase migration of MSCs.

Regulation of focal adhesion turnover in SDF-1α-stimulated migration of mesenchymal stem cells in neural differentiation

Directed migration of the transplanted mesenchymal stem cells (MSCs) to the lesion sites plays a pivotal role in the efficacy of cell-based therapy. Our previous study demonstrates that MSCs under varying neural differentiation states possess different migratory capacities in response to chemoattractants. However, the underlying mechanism has not been fully addressed. Herein, we show that the assembly and turnover of focal adhesions, the phosphorylation of FAK and paxillin, and the reorganisation of F-actin in MSCs are closely related to their differentiation states in response to SDF-1α. Upon SDF-1α stimulation, FAs turnover more rapidly with the most obvious reduction in the existing time of FAs in MSCs of 24-h preinduction that exhibit the most effective migration towards SDF-1α. Further, we confirm that PI3K/Akt and MAPK pathways participate in the regulation of SDF-1α-induced cell migration and FA assembly, and moreover, that the regulatory effects vary greatly depending on the differentiation states. Collectively, these results demonstrate that FA assembly and turnover, which is accompanied with F-actin reorganisation in response to SDF-1α, correlates closely with the differentiation states of MSCs, which might contribute to the different chemotactic responses of these cells, and thus help develop new strategy to improve the efficacy of MSCs-based therapy.

Translating G-CSF as an Adjunct Therapy to Stem Cell Transplantation for Stroke

Among recently investigated stroke therapies, stem cell treatment holds great promise by virtue of their putative ability to replace lost cells, promote endogenous neurogenesis,and produce behavioral and functional improvement through their "bystander effects." Translating stem cell in the clinic, however, presents a number of technical difficulties. A strategy suggested to enhance therapeutic utility of stem cells is combination therapy, i.e., co-transplantation of stem cells or adjunct treatment with pharmacological agents and substrates,which is assumed to produce more profound therapeutic benefits by circumventing limitations of individual treatments and facilitating complementary brain repair processes. We previously demonstrated enhanced functional effects of cotreatment with granulocyte-colony stimulating factor (GCSF)and human umbilical cord blood cell (hUCB) transplantation in animal models of traumatic brain injury (TBI). Here,we suggest that the aforementioned combination therapy may also produce synergistic effects in stroke. Accordingly, G-CSF treatment may reduce expression of pro-inflammatory cytokines and enhance neurogenesis rendering a receptive microenvironment for hUCB engraftment. Adjunct treatment of GCSF with hUCB may facilitate stemness maintenance and guide neural lineage commitment of hUCB cells. Moreover, regenerative mechanisms afforded by G-CSF-mobilized endogenous stem cells, secretion of growth factors by hUCB grafts and G-CSF-recruited endothelial progenitor cells(EPCs), as well as the potential graft–host integration that may promote synaptic circuitry re-establishment could altogether produce more pronounced functional improvement in stroked rats subjected to a combination G-CSF treatment and hUCB transplantation. Nevertheless, differences in pathology and repair processes underlying TBI and stroke deserve consideration when testing the effects of combinatorial G-CSF and hUCB cell transplantation for stroke treatment. Further studies are also required to determine the safety and efficacy of this intervention in both preclinical and clinical stroke studies.