Mesenchymal stem cells and CXC chemokine receptor 4 overexpression improved the therapeutic effect on colitis via mucosa repair

CXCR4 enhances the inhibitory effects of bone mesenchymal stem cells on lung cell apoptosis in a rat model of smoking-induced COPD

Chronic obstructive pulmonary disease is the 3rd leading cause of death worldwide, and the available treatments are unsatisfactory, resulting in a major economic burden. As cellular therapy is commonly used for lung disease, we investigated a treatment with CXCR4-overexpressing BMSCs in a COPD model. We extracted and purified Bone marrow mesenchymal stem cells (BMSCs) from SD rats. COPD apoptosis model was established by cigarette smoke exposure. BMSCs (1 × 106 cells per injection)were transplanted in vivo twice a month during model establishment, and alveolar rupture in the lung was assessed. Lung cell apoptosis was assessed by terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL) analysis, and the concentrations of apoptotic proteins in the lungs were detected by Western blotting. We successfully isolated BMSCs and established CXCR4-overexpressing BMSCs. qRT‒PCR and Western blotting detection both reveal that CXCR4 mRNA level and protein both significantly higher expression in CXCR4-BMSCs than the pBABE-BMSCs. Continuous cigarette smoke exposure caused alveolar septal rupture: In the model group, the alveolar mean linear intercept in the first month was significantly lower than that in the third month (p < 0.05). In the third month, the alveolar mean linear intercept values of the control and CXCR4-BMSC groups were lower than those of the model group (control group p < 0.01, CXCR4-BMSC group p < 0.05), and TUNEL staining revealed that the apoptosis rates of the control and CXCR4-BMSC groups were significantly lower than those of the model group (p < 0.01). Furthermore, the levels of the apoptotic proteins cleaved caspase-8, cleaved caspase-3 and cleaved PARP-1 were higher in the model group than in the control group (p < 0.05) and significantly lower in the CXCR4-BMSC group than in the model group (p < 0.05). The transplantation of CXCR4-overexpressing BMSCs during COPD model generation significantly inhibited apoptosis via the extrinsic apoptosis pathway. CXCR4 enhances the inhibitory effects of bone mesenchymal stem cells on lung cell apoptosis in a rat model of smoking-induced COPD.

Improved efficacy of mesenchymal stromal cells stably expressing CXCR4 and IL-10 in a xenogeneic graft versus host disease mouse model

Previous clinical trials have shown that mesenchymal stromal cells (MSCs) can modulate graft versus host disease (GvHD) after allogeneic hematopoietic transplantation, although with variable efficacy. To improve the anti-GvHD effect of these cells, adipose tissue derived-human MSCs (Ad-MSCs) were transduced with a lentiviral vector conferring stable expression of CXCR4, a molecule involved in cell migration to inflamed sites, and IL-10, a cytokine with potent anti-inflammatory properties. In vitro experiments showed that the expression of these molecules in Ad-MSCs (named CXCR4-IL10-MSCs) efficiently enhanced their migration towards SDF-1α and also improved their immunomodulatory properties compared to unmodified Ad-MSCs (WT-MSCs). Moreover, using a humanized GvHD mouse model, CXCR4-IL10-MSCs showed improved therapeutic effects, which were confirmed by histopathologic analysis in the target organs. Additionally, compared to WT-MSCs, CXCR4-IL10-MSCs induced a more marked reduction in the number of pro-inflammatory Th1 and Th17 cells, a higher polarization towards an anti-inflammatory T cell profile (CD3⁺-IL10⁺ cells), and increased the number of regulatory T and B cells. Our in vitro and in vivo studies strongly suggest that CXCR4-IL10-MSCs should constitute an important new generation of MSCs for the treatment of GvHD in patients transplanted with allogeneic hematopoietic grafts.

Strategies to improve the effect of mesenchymal stem cell therapy on inflammatory bowel disease

Inflammatory bowel disease (IBD) includes Crohn’s disease and ulcerative colitis and is an idiopathic, chronic inflammatory disease of the colonic mucosa. The occurrence of IBD, causes irreversible damage to the colon and increases the risk of carcinoma. The routine clinical treatment of IBD includes drug treatment, endoscopic treatment and surgery. The vast majority of patients are treated with drugs and biological agents, but the complete cure of IBD is difficult. Mesenchymal stem cells (MSCs) have become a new type of cell therapy for the treatment of IBD due to their immunomodulatory and nutritional functions, which have been confirmed in many clinical trials. This review discusses some potential mechanisms of MSCs in the treatment of IBD, summarizes the experimental results, and provides new insights to enhance the therapeutic effects of MSCs in future applications.

Silica Nanoparticle Internalization Improves Chemotactic Behaviour of Human Mesenchymal Stem Cells Acting on the SDF1α/CXCR4 Axis

Human mesenchymal stem cell (hMSC)-based therapy is an emerging resource in regenerative medicine. Despite the innate ability of hMSCs to migrate to sites of injury, homing of infused hMSCs to the target tissue is inefficient. It was shown that silica nanoparticles (SiO₂-NPs), previously developed to track the stem cells after transplantation, accumulated in lysosomes leading to a transient blockage of the autophagic flux. Since CXCR4 turnover is mainly regulated by autophagy, we tested the effect of SiO₂-NPs on chemotactic migration of hMSCs along the SDF1α/CXCR4 axis that plays a pivotal role in directing MSC homing to sites of injury. Our results showed that SiO₂-NP internalization augmented CXCR4 surface levels. We demonstrated that SiO₂-NP-dependent CXCR4 increase was transient, and it reversed at the same time as lysosomal compartment normalization. Furthermore, the autophagy inhibitor Bafilomycin-A1 reproduced CXCR4 overexpression in control hMSCs confirming the direct effect of the autophagic degradation blockage on CXCR4 expression. Chemotaxis assays showed that SiO₂-NPs increased hMSC migration toward SDF1α. In contrast, migration improvement was not observed in TNFα/TNFR axis, due to the proteasome-dependent TNFR regulation. Overall, our findings demonstrated that SiO₂-NP internalization increases the chemotactic behaviour of hMSCs acting on the SDF1α/CXCR4 axis, unmasking a high potential to improve hMSC migration to sites of injury and therapeutic efficacy upon cell injection in vivo.

Improving the Efficacy of Mesenchymal Stem/Stromal-Based Therapy for Treatment of Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBD) consisting of persistent and relapsing inflammatory processes of the intestinal mucosa are caused by genetic, environmental, and commensal microbiota factors. Despite recent advances in clinical treatments aiming to decrease inflammation, nearly 30% of patients treated with biologicals experienced drawbacks including loss of response, while others can develop severe side effects. Hence, novel effective treatments are highly needed. Mesenchymal stem/stromal cell (MSCs) therapy is an innovative therapeutic alternative currently under investigation for IBD. MSCs have the inherent capacity of modulating inflammatory immune responses as well as regenerating damaged tissues and are therefore a prime candidate to use as cell therapy in patients with IBD. At present, MSC-based therapy has been shown preclinically to modulate intestinal inflammation, whilst the safety of MSC-based therapy has been demonstrated in clinical trials. However, the successful results in preclinical studies have not been replicated in clinical trials. In this review, we will summarize the protocols used in preclinical and clinical trials and the novel approaches currently under investigation which aim to increase the beneficial effects of MSC-based therapy for IBD.

Pretreatment with licochalcone a enhances therapeutic activity of rat bone marrow mesenchymal stem cells in animal models of colitis

OBJECTIVES

Colitis has a high prevalence rate, limited treatment options, and needs to be solved urgently. Application of Licochacone A (LA) or rBMMSCs alone in the treatment of colitis has a certain but limited effect. This study aims to develop an LA-based strategy to improve mesenchymal stem cells' (MSCs') therapeutic capacity in mice DSS-induced colitis by increasing the number of MSCs migrating to the inflammation site.

MATERIALS AND METHODS

In vivo, we injected MSCs pretreated with LA, MSCs alone, or PBS into the tail vein of colitis mice, and assessed the colon length, disease activity index (DAI) score, body weight, HAI score, and tracked the location of MSCs at day 10. In vitro, we knocked down the CXCR4 gene by siRNA and then treated it with LA, then tested the mRNA level of CXCR4 and the migration ability of group CXCR4, CXCR4+LA, LA, and control to verify the relationship between this effect and the SDF-1-CXCR4 signaling pathway.

RESULTS

The mice that received LA- pretreated MSCs had ameliorated body weight loss, preserved colon morphology, and decreased DAI and histological activity index (HAI) compared with the MSCs group. Besides, the number of MSCs migrating to the inflammation site significantly increased in group LA+MSCs, and expression of CXCR4 significantly increased too. Furthermore, we found that LA could partly revise the decrease of the migration of MSCs and the expression of CXCR4 mRNA caused by CXCR4-siRNA.

CONCLUSION

LA may improve the migration ability of MSCs through increasing CXCR4 expression therapy enhancing their therapeutic activity.

Chemokines and their receptors: predictors of the therapeutic potential of mesenchymal stromal cells

Multipotent mesenchymal stromal cells (MSCs) are promising cellular therapeutics for the treatment of inflammatory and degenerative disorders due to their anti-inflammatory, immunomodulatory and regenerative potentials. MSCs can be sourced from a variety of tissues within the body, but bone marrow is the most frequently used starting material for clinical use. The chemokine family contains many regulators of inflammation, cellular function and cellular migration-all critical factors in understanding the potential potency of a novel cellular therapeutic. In this review, we focus on expression of chemokine receptors and chemokine ligands by MSCs isolated from different tissues. We discuss the differential migratory, angiogenetic and immunomodulatory potential to understand the role that tissue source of MSC may play within a clinical context. Furthermore, this is strongly associated with leukocyte recruitment, immunomodulatory potential and T cell inhibition potential and we hypothesize that chemokine profiling can be used to predict the in vivo therapeutic potential of MSCs isolated from new sources and compare them to BM MSCs.

Immunosuppressive Property of MSCs Mediated by Cell Surface Receptors

In the past decade, mesenchymal stem cells (MSCs) tend to exhibit inherent tropism for refractory inflammatory diseases and engineered MSCs have appeared on the market as therapeutic agents. Recently, engineered MSCs target to cell surface molecules on immune cells has been a new strategy to improve MSC applications. In this review, we discuss the roles of multiple receptors (ICAM-1, Gal-9, PD-L1, TIGIT, CD200, and CXCR4) in the process of MSCs' immunosuppressive properties. Furthermore, we discuss the principles and strategies for developing receptor-regulated MSCs and their mechanisms of action and the challenges of using MSCs as immunosuppressive therapies.

Shattering barriers toward clinically meaningful MSC therapies

More than 1050 clinical trials are registered at FDA.gov that explore multipotent mesenchymal stromal cells (MSCs) for nearly every clinical application imaginable, including neurodegenerative and cardiac disorders, perianal fistulas, graft-versus-host disease, COVID-19, and cancer. Several companies have or are in the process of commercializing MSC-based therapies. However, most of the clinical-stage MSC therapies have been unable to meet primary efficacy end points. The innate therapeutic functions of MSCs administered to humans are not as robust as demonstrated in preclinical studies, and in general, the translation of cell-based therapy is impaired by a myriad of steps that introduce heterogeneity. In this review, we discuss the major clinical challenges with MSC therapies, the details of these challenges, and the potential bioengineering approaches that leverage the unique biology of MSCs to overcome the challenges and achieve more potent and versatile therapies.

Mesenchymal Stromal Cell Homing: Mechanisms and Strategies for Improvement

Mesenchymal stromal cells (MSCs) have been widely investigated for their therapeutic potential in regenerative medicine, owing to their ability to home damaged tissue and serve as a reservoir of growth factors and regenerative molecules. As such, clinical applications of MSCs are reliant on these cells successfully migrating to the desired tissue following their administration. Unfortunately, MSC homing is inefficient, with only a small percentage of cells reaching the target tissue following systemic administration. This attrition represents a major bottleneck in realizing the full therapeutic potential of MSC-based therapies. Accordingly, a variety of strategies have been employed in the hope of improving this process. Here, we review the molecular mechanisms underlying MSC homing, based on a multistep model involving (1) initial tethering by selectins, (2) activation by cytokines, (3) arrest by integrins, (4) diapedesis or transmigration using matrix remodelers, and (5) extravascular migration toward chemokine gradients. We then review the various strategies that have been investigated for improving MSC homing, including genetic modification, cell surface engineering, in vitro priming of MSCs, and in particular, ultrasound techniques, which have recently gained significant interest. Contextualizing these strategies within the multistep homing model emphasizes that our ability to optimize this process hinges on our understanding of its molecular mechanisms. Moving forward, it is only with a combined effort of basic biology and translational work that the potential of MSC-based therapies can be realized.