Mesenchymal stem cell-derived small extracellular vesicles and bone regeneration

Bone Mesenchymal Stem Cell-Derived sEV-Encapsulated Thermosensitive Hydrogels Accelerate Osteogenesis and Angiogenesis by Release of Exosomal miR-21

Angiogenesis has been recognized to play an essential role in remodeling new bone (osteogenesis). Small extracellular vesicles (sEVs), the endogenously secreted nanovesicles by cells, exhibit great potential in the regeneration of bone defects and the realization of cell-free therapy. Chitosan, a natural polysaccharide, can form a thermosensitive injectable hydrogel through the addition of β-glycerophosphate. Herein, we developed injectable thermosensitive hydrogel-encapsulated sEVs derived from bone mesenchymal stem cells, which significantly prolonged delivery and release and synergistically enhanced bone regeneration. sEVs were isolated and characterized, and the physicochemical properties, release kinetics, and biocompatibility of the hydrogels were analyzed. In vitro experiments were performed to investigate osteogenic differentiation, cell proliferation and migration, and tube formation. Thereafter, sEVs were added to the chitosan/β-glycerophosphate hydrogel (sEV@CS/β-GP composite) to repair calvarial defects in rats. The results showed that sEV-loaded hydrogels were biocompatible, exhibiting excellent thermosensitive properties and enhancing bone regeneration. Furthermore, mechanistic studies revealed that exosomal miR-21 targeted SPRY2, thereby promoting angiogenesis. Our study provides new insights on the repair of bone defects with multifunctional controlled-sEV-release hydrogels, which shows great potential in the repair of tissues in the future.

X-Linked Osteogenesis Imperfecta Possibly Caused by a Novel Variant in PLS3

Osteogenesis imperfecta (OI) represents a complex spectrum of genetic bone diseases that occur primarily due to mutations and deletions of the COL1A1 and COL1A2 genes. Recent molecular studies of the network of signaling pathways have contributed to a better understanding of bone remodeling and the pathogenesis of OI caused by mutations in many other genes associated with normal bone mineralization. In this paper, a case of a rare X-linked variant of OI with a change in the gene encoding plastin 3—a protein important for the regulation of the actin cytoskeleton, is presented. A 16-year-old patient developed ten bone fractures caused by minor trauma or injury, including a compression fracture of the second lumbar vertebra during his lifetime. Next-generation sequencing analysis did not show pathologically relevant deviations in the COL1A1 and COL1A2 genes. Targeted gene analyses (Skeletal disorder panel) of the patient, his father, mother and sister were then performed, detecting variants of uncertain significance (VUS) for genes PLS3, FN1 and COL11A2. A variant in the PLS3 gene were identified in the patient, his mother and sister. Since the PLS3 gene is located on the X chromosome, the mother and sister showed no signs of the disease. Although the variant in the PLS3 gene (c.685G>A (p.Gly229Arg)) has not yet been described in the literature, nor is its pathogenicity known, clinical findings combined with genetic testing showed that this variant may explain the cause of X-linked OI in our patient. This rare case of the PLS3 variant of X-linked OI might point to a novel target for personalized therapy in patients with this severe disease.

The Therapeutic Potential of Mesenchymal Stromal Cells for Regenerative Medicine: Current Knowledge and Future Understandings

In recent decades, research on the therapeutic potential of progenitor cells has advanced considerably. Among progenitor cells, mesenchymal stromal cells (MSCs) have attracted significant interest and have proven to be a promising tool for regenerative medicine. MSCs are isolated from various anatomical sites, including bone marrow, adipose tissue, and umbilical cord. Advances in separation, culture, and expansion techniques for MSCs have enabled their large-scale therapeutic application. This progress accompanied by the rapid improvement of transplantation practices has enhanced the utilization of MSCs in regenerative medicine. During tissue healing, MSCs may exhibit several therapeutic functions to support the repair and regeneration of injured tissue. The process underlying these effects likely involves the migration and homing of MSCs, as well as their immunotropic functions. The direct differentiation of MSCs as a cell replacement therapeutic mechanism is discussed. The fate and behavior of MSCs are further regulated by their microenvironment, which may consequently influence their repair potential. A paracrine pathway based on the release of different messengers, including regulatory factors, chemokines, cytokines, growth factors, and nucleic acids that can be secreted or packaged into extracellular vesicles, is also implicated in the therapeutic properties of MSCs. In this review, we will discuss relevant outcomes regarding the properties and roles of MSCs during tissue repair and regeneration. We will critically examine the influence of the local microenvironment, especially immunological and inflammatory signals, as well as the mechanisms underlying these therapeutic effects. Importantly, we will describe the interactions of local progenitor and immune cells with MSCs and their modulation during tissue injury. We will also highlight the crucial role of paracrine pathways, including the role of extracellular vesicles, in this healing process. Moreover, we will discuss the therapeutic potential of MSCs and MSC-derived extracellular vesicles in the treatment of COVID-19 (coronavirus disease 2019) patients. Overall, this review will provide a better understanding of MSC-based therapies as a novel immunoregenerative strategy.

Small extracellular vesicles from menstrual blood-derived mesenchymal stem cells (MenSCs) as a novel therapeutic impetus in regenerative medicine

Menstrual blood-derived mesenchymal stem cells (MenSCs) have great potential in regenerative medicine. MenSC has received increasing attention owing to its impressive therapeutic effects in both preclinical and clinical trials. However, the study of MenSC-derived small extracellular vesicles (EVs) is still in its initial stages, in contrast to some common MSC sources (e.g., bone marrow, umbilical cord, and adipose tissue). We describe the basic characteristics and biological functions of MenSC-derived small EVs. We also demonstrate the therapeutic potential of small EVs in fulminant hepatic failure, myocardial infarction, pulmonary fibrosis, prostate cancer, cutaneous wound, type-1 diabetes mellitus, aged fertility, and potential diseases. Subsequently, novel hotspots with respect to MenSC EV-based therapy are proposed to overcome current challenges. While complexities regarding the therapeutic potential of MenSC EVs continue to be unraveled, advances are rapidly emerging in both basic science and clinical medicine. MenSC EV-based treatment has great potential for treating a series of diseases as a novel therapeutic strategy in regenerative medicine.

The Multi-Therapeutic Role of MSCs in Diabetic Nephropathy

Diabetic nephropathy (DN) is one of the most common diabetes mellitus (DM) microvascular complications, which always ends with end-stage renal disease (ESRD). Up to now, as the treatment of DN in clinic is still complicated, ESRD has become the main cause of death in diabetic patients. Mesenchymal stem cells (MSCs), with multi-differentiation potential and paracrine function, have attracted considerable attention in cell therapy recently. Increasing studies concerning the mechanisms and therapeutic effect of MSCs in DN emerged. This review summarizes several mechanisms of MSCs, especially MSCs derived exosomes in DN therapy, including hyperglycemia regulation, anti-inflammatory, anti-fibrosis, pro-angiogenesis, and renal function protection. We also emphasize the limitation of MSCs application in the clinic and the enhanced therapeutic role of pre-treated MSCs in the DN therapy. This review provides balanced and impartial views for MSC therapy as a promising strategy in diabetic kidney disease amelioration.

Mesenchymal stem cell-derived small extracellular vesicles and bone regeneration

Mesenchymal stem cells (MSCs) and MSC-derived small extracellular vesicles (sEVs) are promising candidates for cell-based and cell-free regenerative medicine, respectively. By virtue of their multiple lineage differentiation capacity, MSCs have been implicated as an ideal tool for bone and cartilage regeneration. However, later observations attributed such regenerative effects to MSC-secreted paracrine factors. Exosomes, endosomal originated sEVs carrying lipid, protein and nucleic acid cargoes, were identified as components of the MSC secretome and propagated the key regenerative and immunoregulatory characteristics of parental MSCs. Here, exosome biogenesis, the molecular composition of exosomes, sEV-cell interactions and the effects on key bone homeostasis cells are reviewed. MSC-derived sEVs show to promote neovascularization and bone and cartilage regeneration in preclinical disease models. The mechanisms include the transfer of molecules, including microRNAs, mRNAs and proteins, to other key cells. MSC-derived sEVs are interesting candidates as biopharmaceuticals for drug delivery and for the engineering of biologically functionalized materials. Although major exploratory efforts have been made for therapeutic development, the secretion, distribution and biological effects of MSC-derived sEVs in bone and cartilage regeneration are not fully understood. Moreover, techniques for high-yield production, purity and storage need to be optimized before effective and safe MSC-derived sEVs therapies are realized.

Extracellular Vesicles as Innovative Tool for Diagnosis, Regeneration and Protection against Neurological Damage

Extracellular vesicles (EVs) have recently attracted a great deal of interest as they may represent a new biosignaling paradigm. According to the mode of biogenesis, size and composition, two broad categories of EVs have been described, exosomes and microvesicles. EVs have been shown to carry cargoes of signaling proteins, RNA species, DNA and lipids. Once released, their content is selectively taken up by near or distant target cells, influencing their behavior. Exosomes are involved in cell–cell communication in a wide range of embryonic developmental processes and in fetal–maternal communication. In the present review, an outline of the role of EVs in neural development, regeneration and diseases is presented. EVs can act as regulators of normal homeostasis, but they can also promote either neuroinflammation/degeneration or tissue repair in pathological conditions, depending on their content. Since EV molecular cargo constitutes a representation of the origin cell status, EVs can be exploited in the diagnosis of several diseases. Due to their capability to cross the blood–brain barrier (BBB), EVs not only have been suggested for the diagnosis of central nervous system disorders by means of minimally invasive procedures, i.e., “liquid biopsies”, but they are also considered attractive tools for targeted drug delivery across the BBB. From the therapeutic perspective, mesenchymal stem cells (MSCs) represent one of the most promising sources of EVs. In particular, the neuroprotective properties of MSCs derived from the dental pulp are here discussed.