Precisely targeted drug delivery by mesenchymal stem cells-based biomimetic liposomes to cerebral ischemia-reperfusion injured hemisphere.

The precise and targeted delivery of therapeutic agents to the lesion sites remains a major challenge in treating brain diseases represented by ischemic stroke. Herein, we modified liposomes with mesenchymal stem cells (MSC) membrane to construct biomimetic liposomes, termed MSCsome. MSCsome (115.99 ± 4.03 nm) exhibited concentrated accumulation in the cerebral infarcted hemisphere of mice with cerebral ischemia-reperfusion injury, while showing uniform distribution in the two cerebral hemispheres of normal mice. Moreover, MSCsome exhibited high colocalization with damaged nerve cells in the infarcted hemisphere, highlighting its advantageous precise targeting capabilities over liposomes at both the tissue and cellular levels. Leveraging its superior targeting properties, MSCsome effectively delivered Dl-3-n-butylphthalide (NBP) to the injured hemisphere, making a single-dose (15 mg/kg) intravenous injection of NBP-encapsulated MSCsome facilitate the recovery of motor functions in model mice by improving the damaged microenvironment and suppressing neuroinflammation. This study underscores that the modification of the MSC membrane notably enhances the capacity of liposomes for precisely targeting the injured hemisphere, which is particularly crucial in treating cerebral ischemia-reperfusion injury.

Revolutionizing rheumatoid arthritis therapy: harnessing cytomembrane biomimetic nanoparticles for novel treatment strategies.

Rheumatoid arthritis (RA) is a systemic immune disease with severe implications for joint health. The issue of non-specific drug distribution potentially limits the therapeutic efficacy and increases the risk associated with RA treatment. Researchers employed cytomembrane-coated biomimetic nanoparticles (NPs) to enhance the targeting delivery efficacy to meet the demand for drug accumulation within the affected joints. Furthermore, distinct cytomembranes offer unique functionalities, such as immune cell activation and augmented NP biocompatibility. In this review, the current strategies of RA treatments were summarized in detail, and then an overview of RA's pathogenesis and the methodologies for producing cytomembrane-coated biomimetic NPs was provided. The application of cytomembrane biomimetic NPs derived from various cell sources in RA therapy is explored, highlighting the distinctive attributes of individual cytomembranes as well as hybrid membrane configurations. Through this comprehensive assessment of cytomembrane biomimetic NPs, we elucidate the prospective applications and challenges in the realm of RA therapy, and the strategy of combined therapy is proposed. In the future, cytomembrane biomimetic NPs have a broad therapeutic prospect for RA.

Stem cell-based ischemic stroke therapy: Novel modifications and clinical challenges.

Ischemic stroke (IS) causes severe disability and high mortality worldwide. Stem cell (SC) therapy exhibits unique therapeutic potential for IS that differs from current treatments. SC's cell homing, differentiation and paracrine abilities give hope for neuroprotection. Recent studies on SC modification have enhanced therapeutic effects for IS, including gene transfection, nanoparticle modification, biomaterial modification and pretreatment. These methods improve survival rate, homing, neural differentiation, and paracrine abilities in ischemic areas. However, many problems must be resolved before SC therapy can be clinically applied. These issues include production quality and quantity, stability during transportation and storage, as well as usage regulations. Herein, we reviewed the brief pathogenesis of IS, the "multi-mechanism" advantages of SCs for treating IS, various SC modification methods, and SC therapy challenges. We aim to uncover the potential and overcome the challenges of using SCs for treating IS and convey innovative ideas for modifying SCs.

Targeting cancer-associated fibroblast autophagy renders pancreatic cancer eradicable with immunochemotherapy by inhibiting adaptive immune resistance.

Accumulating evidence suggests that cancer-associated fibroblast (CAF) macroautophagy/autophagy is crucial in tumor development and may be a therapeutic target for pancreatic ductal adenocarcinoma (PDAC). However, the role of CAF autophagy during immune surveillance and cancer immunotherapy is unclear. The present study revealed that the inhibition of CAF autophagy suppresses in vivo tumor development in immune-deficient xenografts. This deletion compromises anti-tumor immunity and anti-tumor efficacy both in vitro and in vivo by upregulating CD274/PDL1 levels in an immune-competent mouse model. A block in CAF autophagy reduced the production of IL6 (interleukin 6), disrupting high desmoplastic TME and decreasing USP14 expression at the transcription level in pancreatic cancer cells. We further identify USP14 as the post-translational factor responsible for downregulating CD274 expression by removing K63 linked-ubiquitination at the K280 residue. Finally, chloroquine diphosphate-loaded mesenchymal stem cell (MSC)-liposomes, by accurately targeting CAFs, inhibited CAF autophagy, improving the efficacy of immunochemotherapy to combat pancreatic cancer.Abbreviation: AIR: adaptive immune resistance; ATRA: all-trans-retinoicacid; CAF: cancer-associated fibroblast; CD274/PDL1: CD274 molecule; CM: conditioned medium; CQ: chloroquine diphosphate; CyTOF: Mass cytometry; FGF2/bFGF: fibroblast growth factor 2; ICB: immune checkpoint blockade; IF: immunofluorescence; IHC: immunohistochemistry; IP: immunoprecipitation; MS: mass spectrometer; MSC: mesenchymal stem cell; PDAC: pancreatic ductal adenocarcinoma; TEM: transmission electron microscopy; TILs: tumor infiltrating lymphocytes; TME: tumor microenvironment; USP14: ubiquitin specific peptidase 14.

Single-cell characterization of deformation and dynamics of mesenchymal stem cells in microfluidic systems: A computational study.

Understanding the homing dynamics of individual mesenchymal stem cells (MSCs) in physiologically relevant microenvironments is crucial for improving the efficacy of MSC-based therapies for therapeutic and targeting purposes. This study investigates the passive homing behavior of individual MSCs in micropores that mimic interendothelial clefts through predictive computational simulations informed by previous microfluidic experiments. Initially, we quantified the size-dependent behavior of MSCs in micropores and elucidated the underlying mechanisms. Subsequently, we analyzed the shape deformation and traversal dynamics of each MSC. In addition, we conducted a systematic investigation to understand how the mechanical properties of MSCs impact their traversal process. We considered geometric and mechanical parameters, such as reduced cell volume, cell-to-nucleus diameter ratio, and cytoskeletal prestress states. Furthermore, we quantified the changes in the MSC traversal process and identified the quantitative limits in their response to variations in micropore length. Taken together, the computational results indicate the complex dynamic behavior of individual MSCs in the confined microflow. This finding offers an objective way to evaluate the homing ability of MSCs in an interendothelial-slit-like microenvironment.

Efficient intervention for pulmonary fibrosis via mitochondrial transfer promoted by mitochondrial biogenesis.

The use of exogenous mitochondria to replenish damaged mitochondria has been proposed as a strategy for the treatment of pulmonary fibrosis. However, the success of this strategy is partially restricted by the difficulty of supplying sufficient mitochondria to diseased cells. Herein, we report the generation of high-powered mesenchymal stem cells with promoted mitochondrial biogenesis and facilitated mitochondrial transfer to injured lung cells by the sequential treatment of pioglitazone and iron oxide nanoparticles. This highly efficient mitochondrial transfer is shown to not only restore mitochondrial homeostasis but also reactivate inhibited mitophagy, consequently recovering impaired cellular functions. We perform studies in mouse to show that these high-powered mesenchymal stem cells successfully mitigate fibrotic progression in a progressive fibrosis model, which was further verified in a humanized multicellular lung spheroid model. The present findings provide a potential strategy to overcome the current limitations in mitochondrial replenishment therapy, thereby promoting therapeutic applications for fibrotic intervention.

Inorganic nanoparticle-integrated mesenchymal stem cells: A potential biological agent for multifaceted applications.

Mesenchymal stem cell (MSC)-based therapies are flourishing. MSCs could be used as potential therapeutic agents for regenerative medicine due to their own repair function. Meanwhile, the natural predisposition toward inflammation or injury sites makes them promising carriers for targeted drug delivery. Inorganic nanoparticles (INPs) are greatly favored for their unique properties and potential applications in biomedical fields. Current research has integrated INPs with MSCs to enhance their regenerative or antitumor functions. This model also allows the in vivo fate tracking of MSCs in multiple imaging modalities, as many INPs are also excellent contrast agents. Thus, INP-integrated MSCs would be a multifunctional biologic agent with great potential. In this review, the current roles performed by the integration of INPs with MSCs, including (i) enhancing their repair and regeneration capacity via the improvement of migration, survival, paracrine, or differentiation properties, (ii) empowering tumor-killing ability through agent loaded or hyperthermia, and (iii) conferring traceability are summarized. An introduction of INP-integrated MSCs for simultaneous treatment and tracking is also included. The promising applications of INP-integrated MSCs in future treatments are emphasized and the challenges to their clinical translation are discussed.

Exosome-Based Regimen Rescues Endometrial Fibrosis in Intrauterine Adhesions Via Targeting Clinical Fibrosis Biomarkers.

Intrauterine adhesions (IUA), which is characterized by endometrial fibrosis, continue to be the most common cause of uterine infertility globally. Our work revealed that 3 fibrotic progression markers (Vimentin, COL5A2, and COL1A1) were significantly increased in the endometrium of IUA patients. Mesenchymal stem cell-derived exosomes (EXOs) have been recently revealed as a cell-free therapy for fibrosis diseases. Nevertheless, the application of EXOs is restricted by the short residency duration in the target tissue. To overcome this limitation, herein, we reported an exosome-based regimen (EXOs-HP) that thermosensitive poloxamer hydrogel possessed the ability to efficiently promote the residency duration of EXOs in the uterine cavity. By downregulating fibrotic progression markers (Vimentin, COL5A2, and COL1A1), EXOs-HP could significantly restore the function and structure of the injured endometrium in the IUA model. Our work provides the theoretical and experimental foundation of EXOs-HP in treating IUA, highlighting the clinical potential of topical EXOs-HP delivery system in IUA patients.

Cell membrane-coated nanoparticles: a novel multifunctional biomimetic drug delivery system.

Recently, nanoparticle-based drug delivery systems have been widely used for the treatment, prevention, and detection of diseases. Improving the targeted delivery ability of nanoparticles has emerged as a critical issue that must be addressed as soon as possible. The bionic cell membrane coating technology has become a novel concept for the design of nanoparticles. The diverse biological roles of cell membrane surface proteins endow nanoparticles with several functions, such as immune escape, long circulation time, and targeted delivery; therefore, these proteins are being extensively studied in the fields of drug delivery, detoxification, and cancer treatment. Furthermore, hybrid cell membrane-coated nanoparticles enhance the beneficial effects of monotypic cell membranes, resulting in multifunctional and efficient delivery carriers. This review focuses on the synthesis, development, and application of the cell membrane coating technology and discusses the function and mechanism of monotypic/hybrid cell membrane-modified nanoparticles in detail. Moreover, it summarizes the applications of cell membranes from different sources and discusses the challenges that may be faced during the clinical application of bionic carriers, including their production, mechanism, and quality control. We hope this review will attract more scholars toward bionic cell membrane carriers and provide certain ideas and directions for solving the existing problems.

New idea to promote the clinical applications of stem cells or their extracellular vesicles in central nervous system disorders: Combining with intranasal delivery.

The clinical translation of stem cells and their extracellular vesicles (EVs)-based therapy for central nervous system (CNS) diseases is booming. Nevertheless, the insufficient CNS delivery and retention together with the invasiveness of current administration routes prevent stem cells or EVs from fully exerting their clinical therapeutic potential. Intranasal (IN) delivery is a possible strategy to solve problems as IN route could circumvent the brain‒blood barrier non-invasively and fit repeated dosage regimens. Herein, we gave an overview of studies and clinical trials involved with IN route and discussed the possibility of employing IN delivery to solve problems in stem cells or EVs-based therapy. We reviewed relevant researches that combining stem cells or EVs-based therapy with IN administration and analyzed benefits brought by IN route. Finally, we proposed possible suggestions to facilitate the development of IN delivery of stem cells or EVs.

From vaccines to nanovaccines: A promising strategy to revolutionize rheumatoid arthritis treatment.

Rheumatoid arthritis (RA) is a joint-related autoimmune disease that is difficult to cure. Most therapeutics act to alleviate the symptoms but not correct the causes of RA. Novel strategies that specifically target the causes are highly needed for RA management. Currently, early interruption of RA is increasingly suggested but the corresponding therapeutics are not available. Vaccines that have shown great success to combat infection, cancer, degenerative diseases, autoimmune diseases, etc. are ideal candidates for a new generation of anti-RA therapeutics to correct the causes and prevent RA or interrupt RA in early phases. Anti-RA vaccines can be divided into two major categories. One is to induce neutralizing antibodies and the other is to induce antigen-specific immune tolerance. The vaccines are inherently linked to nanotechnology because they usually need a biomacromolecule or carrier to provoke sufficient immune responses. In the past decade, designed nanocarriers such as nanoparticles, liposomes, nanoemulsion, etc., have been applied to optimize the vaccines for autoimmune disease treatment. Nanotechnology endows vaccines with a higher biostability, tunable in vivo behavior, better targeting, co-delivery with stimulatory agents, regulatory effects on immune responses, etc. In this review, unmet medical needs for RA treatment and anti-RA vaccinology are first introduced. The development of anti-RA therapies from vaccines to nanovaccines are then reviewed and perspectives on how nanotechnology promotes vaccine development and advancement are finally provided. In addition, challenges for anti-RA vaccine development are summarized and advantages of nanovaccines are analyzed. In conclusion, nanovaccines will be a promising strategy to revolutionize the treatment of RA by correcting the causes in an early phase of RA.

The in vivo fate and targeting engineering of crossover vesicle-based gene delivery system.

Exosomes and biomimetic vesicles are widely used for gene delivery because of their excellent gene loading capacity and stability and their natural targeting delivery potential. These vesicles take advantages of both cell-based bioactive delivery system and synthetical lipid-derived nanovectors to form crossover characteristics. To further optimize the specific targeting properties of crossover vesicles, studies of their in vivo fate and various engineering approaches including nanobiotechnology are required. This review describes the preparation process of exosomes and biomimetic vesicles, and summarizes the mechanism of loading and delivery of nucleic acids or gene editing systems. We provide a comprehensive overview of the techniques employed for preparing the targeting crossover vesicles based on their cellular uptake and targeting mechanism. To delineate the future prospects of crossover vesicle gene delivery systems, various challenges and clinical applications of vesicles have also been discussed.

Peptide nano-blanket impedes fibroblasts activation and subsequent formation of pre-metastatic niche.

There is evidence to suggest that the primary tumor induces the formation of a pre-metastatic niche in distal organs by stimulating the production of pro-metastatic factors. Given the fundamental role of the pre-metastatic niche in the development of metastases, interruption of its formation would be a promising strategy to take early action against tumor metastasis. Here we report an enzyme-activated assembled peptide FR17 that can serve as a "flame-retarding blanket" in the pre-metastatic niche specifically to extinguish the "fire" of tumor-supportive microenvironment adaption. We show that the in-situ assembled peptide nano-blanket inhibits fibroblasts activation, suppressing the remodeling of the metastasis-supportive host stromal tissue, and reversing vascular destabilization and angiogenesis. Furthermore, we demonstrate that the nano-blanket prevents the recruitment of myeloid cells to the pre-metastatic niche, regulating the immune-suppressive microenvironment. We show that FR17 administration effectively inhibits the formation of the pulmonary pre-metastatic niche and postoperative metastasis, offering a therapeutic strategy against pre-metastatic niche formation.

Mesenchymal stem cells: A living carrier for active tumor-targeted delivery.

The strategy of using mesenchymal stem cells (MSCs) as a living carrier for active delivery of therapeutic agents targeting tumor sites has been attempted in a wide range of studies to validate the feasibility and efficacy for tumor treatment. This approach reveals powerful tumor targeting and tumor penetration. In addition, MSCs have been confirmed to actively participate in immunomodulation of the tumor microenvironment. Thus, MSCs are not inert delivery vehicles but have a strong impact on the fate of tumor cells. In this review, these active properties of MSCs are addressed to highlight the advantages and challenges of using MSCs for tumor-targeted delivery. In addition, some of the latest examples of using MSCs to carry a variety of anti-tumor agents for tumor-targeted therapy are summarized. Recent technologies to improve the performance and safety of this delivery strategy will be introduced. The advances, applications, and challenges summarized in this review will provide a general understanding of this promising strategy for actively delivering drugs to tumor tissues.

Iron oxide nanoparticles augment the intercellular mitochondrial transfer-mediated therapy.

The transfer of mitochondria between cells has recently been revealed as a spontaneous way to protect the injured cells. However, the utilization of this natural transfer process for disease treatment is so far limited by its unsatisfactory transfer efficiency and selectivity. Here, we demonstrate that iron oxide nanoparticles (IONPs) can augment the intercellular mitochondrial transfer from human mesenchymal stem cells (hMSCs) selectively to diseased cells, owing to the enhanced formation of connexin 43­containing gap junctional channels triggered by ionized IONPs. In a mouse model of pulmonary fibrosis, the IONP-engineered hMSCs achieve a remarkable mitigation of fibrotic progression because of the promoted intercellular mitochondrial transfer, with no serious safety issues identified. The present study reports a potential method of using IONPs to enable hMSCs for efficient and safe transfer of mitochondria to diseased cells to restore mitochondrial bioenergetics.

Iron Oxide Nanoparticles Promote Cx43-Overexpression of Mesenchymal Stem Cells for Efficient Suicide Gene Therapy during Glioma Treatment.

Background: Mesenchymal stem cells (MSCs) have been applied as a promising vehicle for tumour-targeted delivery of suicide genes in the herpes simplex virus thymidine kinase (HSV-tk)/ganciclovir (GCV) suicide gene therapy against malignant gliomas. The efficiency of this strategy is largely dependent on the bystander effect, which relies on high suicide gene expression levels and efficient transportation of activated GCV towards glioma cells. However, up to now, the methods to enhance the bystander effect of this strategy in an efficient and safe way are still lacking and new approaches to improve this therapeutic strategy are required. Methods: In this study, MSCs were gene transfected using magnetosome-like ferrimagnetic iron oxide nanochains (MFIONs) to highly express HSV-tk. Both the suicide and bystander effects of HSV-tk expressed MSCs (MSCs-tk) were quantitatively evaluated. Connexin 43 (Cx43) expression by MSCs and glioma cells was measured under different treatments. Intercellular communication between MSCs and C6 glioma cells was examined using a dye transfer assay. Glioma tropism and the bio-distribution of MSCs-tk were observed. Anti-tumour activity was investigated in the orthotopic glioma of rats after intravenous administration of MSCs-tk followed by intraperitoneal injection of GCV. Results: Gene transfection using MFIONs achieved sufficient expression of HSV-tk and triggered Cx43 overexpression in MSCs. These Cx43 overexpressing MSCs promoted gap junction intercellular communication (GJIC) between MSCs and glioma cells, resulting in significantly inhibited growth of glioma through an improved bystander effect. Outstanding tumour targeting and significantly prolonged survival with decreased tumour size were observed after the treatment using MFION-transfected MSCs in glioma model rats. Conclusion: Our results show that iron oxide nanoparticles have the potential to improve the suicide gene expression levels of transfected MSCs, while promoting the GJIC formation between MSCs and tumour cells, which enhances the sensitivity of glioma cells to HSV-tk/GCV suicide gene therapy.

Active stealth and self-positioning biomimetic vehicles achieved effective antitumor therapy.

Mesenchymal stem cells (MSCs) are recognized as promising drug delivery vehicles. However, the limitation of drug loading capacity and safety considerations are two obstacles to the further application of MSCs. Here, we report MSC membrane-coated mesoporous silica nanoparticles (MSN@M) that maintain the active stealth and self-positioning drug delivery abilities of MSCs and resolve issues related to MSCs-mediated drug delivery. MSN@M was established through uniformly integrating MSC membrane onto a mesoporous silica nanoparticle (MSN) core by sonication. Reduced clearance of phagocytes mediated by CD47 marker on MSC membrane was observed in vitro, which explained the only ~ 25% clearance rate of MSN@M compared with MSN in vivo within 24 h. MSN@M also showed stronger tumor targeting and penetration ability compared with MSN in HepG2 tumor bearing mice. Simultaneously, MSN@M exhibited strong capacity for drug loading and sustained drug release ability of MSN when loaded with doxorubicin (DOX), the drug loading of MSN@M increased ~ 5 folds compared with MSC membrane. In HepG2 xenograft mice, DOX-loaded MSN@M effectively inhibited the growth of tumors and decreased the side effects of treatment by decreasing the exposure of other tissues to DOX. Consequently, our MSN@M may serve as alternative vehicles for MSCs and provide more options for antitumor treatment.

Neural Stem Cells Transfected with Reactive Oxygen Species-Responsive Polyplexes for Effective Treatment of Ischemic Stroke.

Neural stem cells (NSCs), capable of ischemia-homing, regeneration, and differentiation, exert strong therapeutic potentials in treating ischemic stroke, but the curative effect is limited in the harsh microenvironment of ischemic regions rich in reactive oxygen species (ROS). Gene transfection to make NSCs overexpress brain-derived neurotrophic factor (BDNF) can enhance their therapeutic efficacy; however, viral vectors must be used because current nonviral vectors are unable to efficiently transfect NSCs. The first polymeric vector, ROS-responsive charge-reversal poly[(2-acryloyl)ethyl(p-boronic acid benzyl)diethylammonium bromide] (B-PDEA), is shown here, that mediates efficient gene transfection of NSCs and greatly enhances their therapeutics in ischemic stroke treatment. The cationic B-PDEA/DNA polyplexes can effectively transfect NSCs; in the cytosol, the B-PDEA is oxidized by intracellular ROS into negatively charged polyacrylic acid, quickly releasing the BDNF plasmids for efficient transcription and secreting a high level of BDNF. After i.v. injection in ischemic stroke mice, the transfected NSCs (BDNF-NSCs) can home to ischemic regions as efficiently as the pristine NSCs but more efficiently produce BDNF, leading to significantly augmented BDNF levels, which in turn enhances the mouse survival rate to 60%, from 0% (nontreated mice) or ≈20% (NSC-treated mice), and enables more rapid and superior functional reconstruction.

Uniformly sized iron oxide nanoparticles for efficient gene delivery to mesenchymal stem cells.

Recent advances in nanomaterials have made iron oxide nanoparticles (IONPs) as an innovative approach for the delivery of genes. However, the effectiveness of IONPs-assisted gene delivery is currently suffering from their poor uniformity, which not only exhibits detrimental effect on the magnetic property, but also leads to the poor reproducibility to maintain the optimal gene delivery. To this end, the present study developed extremely uniform 15 nm-sized IONPs with a good monodispersity in water phase. These ultra-uniform IONPs exhibit notable potentials for an efficient gene delivery to human mesenchymal stem cells (hMSCs) with the assistance of magnetic force, which partly owes to their abilities to facilitate the cellular uptake, as well as to induce the rapid DNA release and the following nuclear transport. Besides, no significant detrimental effects of these IONPs are observed either on the proliferation or the multi-lineage differentiation potential of hMSCs. The current study highlights the potential advantages of designing extremely uniform magnetic nanomaterials for an efficient and safe delivery of genes to stem cells.

Lower-Molecular-Weight Chitosan-Treated Polyethyleneimine: a Practical Strategy For Gene Delivery to Mesenchymal Stem Cells.

BACKGROUND/AIMS: Genetic modification of mesenchymal stem cells (MSCs) is an essential requirement for their use as a delivery vehicle. To achieve higher transfection efficiency and better reproducibility than previously synthesized chitosan (100 kDa)-polyethylenimine (PEI; 1200 Da), we synthesized a low molecular weight PEI (1200 Da)-grafted chitosan (50 kDa) (CP). METHODS: Safety of CP/DNA or PEI (25 kDa)/DNA was evaluated by an MTT assay using A549 cells or MSCs and a zebrafish embryo model. Effects of CP/DNA on the characteristics of MSCs were evaluated using flow cytometry. Additionally, a pGL3 plasmid was used to investigate the transfection efficiency of PEI (25 kDa), chitosan (100 kDa)-PEI (1200 Da), and CP with different N/P mass ratios on A549 cells and MSCs. Furthermore, CP/pGL3 was used to investigate the effect of serum on transfection, and intracellular transport was assessed by observing the intracellular location of DNA using laser scanning confocal microscopy. In addition, the effect of endocytosis on transfection efficiency was evaluated using A549 cells pre-treated with different inhibitors. Investigations related to analysis of transfection efficiency were all performed using the BCA protein assay to standardize the data. Furthermore, TGF-ß1-and CXCR4-expressing plasmids were applied to evaluate the gene transfer efficiency of CP, including its effects on the osteogenic differentiation and migratory ability of MSCs. RESULTS: The safety evaluation demonstrated that CP/DNA had significantly lower toxicity than PEI (25 kDa)/DNA. Additionally, DNA entered MSCs transfected by CP without changing their properties, while the examination of intracellular transport demonstrated that CP/pGL3 was internalized rapidly into MSCs. Furthermore, studies of the internalization mechanism showed that CP/pGL3 complexes entered the cells through caveolae-mediated endocytosis, thereby suggesting that the CP coating helped DNA enter A549 cells without the requirement for receptors. Compared to PEI (25 kDa), the interference of serum on transfection was reduced significantly with the use of CP in both A549 cells and MSCs. To evaluate the effects of gene delivery using the constructed CP complex and the possibility of obtaining gene-engineered MSCs, TGF-ß1- and CXCR4-expressing plasmids were successfully delivered into MSCs, confirming their ability to induce osteogenesis and change the migratory ability of MSCs, respectively. CONCLUSION: These results demonstrated that CP could be used to deliver genes into MSCs and could potentially be used in gene therapy based on MSCs.