We have collected the most exciting new researches in the field of genetics and cellular research in the past week.
Exosomes derived from hypoxic mesenchymal stem cells restore ovarian function by enhancing angiogenesis
Background
hucMSC-exosomes can be engineered to strengthen their therapeutic potential, and the present study aimed to explore whether hypoxic preconditioning can enhance the angiogenic potential of hucMSC-exosomes in an experimental model of POF.
Methods
Primary hucMSCs and ROMECs were isolated from fresh tissue samples and assessed through a series of experiments. Exosomes were isolated from hucMSCs under normoxic or hypoxic conditions (norm-Exos and hypo-Exos, respectively) and then characterized using classic experimental methods. Based on a series of angiogenesis-related assays, we found that hypo-Exos significantly promoted ROMEC proliferation, migration, and tube formation and increased angiogenesis-promoting molecules in vitro. Histology, immunohistochemistry, and immunofluorescence experiments in a rat model of POF demonstrated that hypoxia pretreatment strengthens the therapeutic angiogenic effect of hucMSC-exosomes in vivo. Subsequently, high-throughput miRNA sequencing, qRT‑PCR analysis, and western blotting were employed to identify the potential molecular mechanism.
Results
We found that hypo-Exos enhance endothelial function and angiogenesis via the transfer of miR-205-5p in vitro and in vivo. Finally, based on the results of bioinformatics analysis, dual luciferase reporter assays, and gain- and loss-of-function studies, we found evidence indicating that exosomal miR-205-5p enhances angiogenesis by targeting the PTEN/PI3K/AKT/mTOR signalling pathway. These results indicated for the first time that exosomes derived from hypoxia-conditioned hucMSCs strongly enhance angiogenesis via the transfer of miR-205-5p by targeting the PTEN/PI3K/AKT/mTOR signalling pathway.
Conclusions
Our findings provide a theoretical basis and demonstrate the potential application of a novel cell-free approach with stem cell-derived products in the treatment of POF.
Overexpression of Heme Oxygenase 1 Enhances the Neuroprotective Effects of Exosomes in Subarachnoid Hemorrhage by Suppressing Oxidative Stress and Endoplasmic Reticulum Stress
Aims
This study aims to elucidate the therapeutic effects and underlying mechanisms of exosomes derived from Heme oxygenase 1 (HO-1)-overexpressing human umbilical cord mesenchymal stem cells (ExoHO−1) in a subarachnoid hemorrhage (SAH) mouse model.
Methods
In this study, exosomes were identified using Western blotting, particle analysis, and transmission electron microscopy. The effect of ExoHO−1 and ExoCtrl on the neurological function of SAH mice was assessed using the Garcia scoring system, Beam balance, Rotarod test, and Morris water maze test. Neuronal apoptosis and survival were evaluated through TUNEL and Nissl staining. Levels of oxidative and endoplasmic reticulum stress were measured via immunofluorescence, Western blotting, DHE staining, enzyme-linked immunosorbent assay, and commercial kits.
Results
HO-1-overexpressing human umbilical cord mesenchymal stem cells encapsulated HO-1 into their exosomes. ExoHO−1 significantly enhanced both short-term and long-term neurological function protection. By reducing the activation of the PERK/CHOP/Caspase12 pathway and decreasing oxidative stress levels, ExoHO−1 effectively inhibited neuronal apoptosis in the ipsilateral temporal cortex.
Conclusion
ExoHO−1 enhances the therapeutic efficacy of exosomes in SAH mice by countering neuronal apoptosis, primarily through the suppression of oxidative and endoplasmic reticulum stress.
Exosomal non-coding RNAs: Emerging insights into therapeutic potential and mechanisms in bone healing
Exosomes are nano-sized extracellular vesicles (EVs) released by diverse types of cells, which affect the functions of targeted cells by transporting bioactive substances. As the main component of exosomes, non-coding RNA (ncRNA) is demonstrated to impact multiple pathways participating in bone healing. Herein, this review first introduces the biogenesis and secretion of exosomes, and elucidates the role of the main cargo in exosomes, ncRNAs, in mediating intercellular communication. Subsequently, the potential molecular mechanism of exosomes accelerating bone healing is elucidated from the following four aspects: macrophage polarization, vascularization, osteogenesis and osteoclastogenesis. Then, we systematically introduce construction strategies based on modified exosomes in bone regeneration field. Finally, the clinical trials of exosomes for bone healing and the challenges of exosome-based therapies in the biomedical field are briefly introduced, providing solid theoretical frameworks and optimization methods for the clinical application of exosomes in orthopedics.
Adipose Mesenchymal Stem Cell-Derived Exosomes as Nanocarriers for Treating Musculoskeletal Disorders
Musculoskeletal disorders are a series of diseases involving bone, muscle, cartilage, and tendon, mainly caused by chronic strain, degenerative changes, and structural damage due to trauma. The disorders limit the function of patients due to pain and significantly reduce their quality of life. In recent years, adipose-derived mesenchymal stem cells have been extensively applied in regeneration medicine research due to their particular abilities of self-renewal, differentiation, and targeted homing and are more easily accessed compared with other sources. The paracrine effect of ADSCs plays a crucial role in intercellular communication by releasing mass mediators, including cytokines and growth factors, particularly the exosomes they secrete. Not only do these exosomes possess low immunogenicity, low toxicity, and an enhanced ability to penetrate a bio-barrier, but they also inherit their parent cells’ characteristics and carry various bioactive molecules to release to targeted cells, modulating their biological process. Meanwhile, these characteristics also make exosomes a natural nanocarrier capable of targeted drug delivery to specific sites, enhancing the bioavailability of drugs within the body and achieving precision therapy with fewer toxic side effects. Furthermore, the integration of exosomes with tissue engineering and chemical modification strategies can also significantly enhance their efficacy in facilitating tissue repair. However, the current research on ADSC-Exos for improving MSDs remains at an early stage and needs further exploration. Therefore, this review summarized the ADSC-Exo as a nanodrug carrier characteristics and mechanism in the treatment of fracture, osteoporosis, osteoarthritis, intervertebral disc degeneration, and tendon injury, which push forward the research progress of ADSC-Exo therapy for MSDs.
Ligand-based Exosome Affinity Purification (LEAP) Column Chromatography: A Tool for Clinical Applications
Exosomes are nano-sized extracellular vesicles that play essential roles in intercellular communication, carrying biomolecules such as proteins, lipids, and RNAs that can influence physiological and pathological processes. The isolation of pure exosomes is critical for both basic research and clinical applications, including diagnostics and therapeutics. Traditional exosome isolation techniques, such as ultracentrifugation, lack specificity and may yield impure samples, making the need for advanced isolation techniques evident. Ligand-based exosome affinity purification (LEAP) column chromatography has emerged as a novel method that utilizes specific ligands targeting exosome surface markers, providing a highly specific, gentle, and scalable approach to exosome isolation. This mini review explores LEAP chromatography’s mechanism, benefits, and potential for clinical applications, emphasizing its g.rowing importance in exosome-based diagnostics and therapies.
Exosomes secreted from human-derived adipose stem cells prevent progression of osteonecrosis of the femoral head
Background Osteonecrosis of the femoral head (ONFH) primarily affects young individuals and is a leading cause of total hip arthroplasty in this population. Joint-preserving regenerative therapies involving core decompression (CD), enhanced with cells, growth factors, and bone substitutes, have been developed but lack extensive validation. Exosomes are emerging as a promising regenerative therapy. Human adipose stem cell (hADSC)-derived exosomes exhibit angiogenic and wound-healing effects on damaged and diseased tissues, suggesting their potential efficacy in treating early-stage ONFH. We aimed to investigate the efficacy of hADSC-derived exosomes based on CD in a medium-sized animal model (rabbit). Methods Exosomes were extracted using the ultrafiltration filter technique from the culture supernatants of two types of hADSCs. Characterization of exosomes was performed through nanoparticle tracking analysis, transmission electron microscopy, and the detection of specific biomarkers (CD9, CD63, and CD81) by western blotting. Eighteen rabbits underwent surgical vascular occlusion and intramuscular corticosteroid injections to induce ONFH. Concurrently, CD treatment with local administration of hADSC-derived exosomes (exosome group) or saline (control group) was performed. Femoral heads were harvested at 4, 8, and 12 weeks postoperatively and evaluated using micro-computed tomography and tissue staining to assess the protective effects on osteonecrosis, angiogenesis, and osteogenesis. Results Exosomes had average particle concentrations of 1.8 × 10¹² or 1.8 × 10⁹ particles/mL, with particle size distributions averaging 61.2 ± 14.7 or 123.1 ± 46.3 nm, and were confirmed by specific biomarkers. The exosome group exhibited a significant reduction in the severe progression of ONFH to stages 3 or 4 of the modified Ficat and Arlet classification, compared to the control group, which had four cases of stages 3 or 4. The exosome group showed significantly fewer empty lacunae in the subchondral bone area (p < 0.05) and significantly less articular cartilage injury (p < 0.05) compared to the corresponding in the control group. There were no significant differences in the microvessel number, bone trabecular structure, or volume of new bone in the medial region of the CD. Conclusions hADSC-derived exosomes can prevent the progression of ONFH by inhibiting osteonecrosis and cartilage damage. The ultrafiltration filter technique is effective for exosome extraction, indicating that exosomes hold potential as a therapeutic agent for ONFH.
Exosomes secreted from M2-polarized macrophages inhibit osteoclast differentiation via CYLD
Objective: Bone resorption mediated by osteoclast differentiation induces the occurrence of bone-related diseases. Macrophages, an origin of osteoclasts, whose M2 type can reduce inflammation-induced bone damage. We aimed to investigate the effect of M2 macrophage-derived exosomes on osteoclast formation and elucidate its underlying mechanism.
Materials and methods: Exosomes were isolated from M2 macrophages (M2-exo) and were used to treat osteoclast-like cells. Osteoclast formation was evaluated using tartrate-resistant acid phosphatase, quantitative real-time polymerase chain reaction (qRT-PCR), and Western blotting. The molecular mechanism of M2-exo function was analyzed by qRT-PCR, phosphor-kinase array analysis, and Western blotting.
Results: M2-exo was internalized by osteoclasts and inhibited osteoclast differentiation in vitro. Moreover, CYLD was highly expressed in M2 macrophages and M2-exo-treated osteoclasts, and knockdown of it abrogated the inhibition of osteoclast differentiation caused by M2-exo. Additionally, CYLD suppressed the phosphorylation of STAT3, and STAT3 activator colivelin reversed the inhibition of osteoclast differentiation induced by CYLD overexpression.
Conclusion: M2-exo inhibits osteoclast differentiation via delivering CYLD, which inactivates STAT3 signaling. These findings may provide a novel therapeutic option for bone diseases including periodontitis.
Exosomes from mesenchymal stem cells overexpressing MIF enhance myocardial repair
Accumulating evidence has shown that mesenchymal stem cell (MSC)-derived exosomes (exo) mediate cardiac repair following myocardial infarction (MI). Macrophage migration inhibitory factor (MIF), a proinflammatory cytokine, plays a critical role in regulating cell homeostasis. This study aimed to investigate the cardioprotective effects of exo secreted from bone marrow-MSCs (BM-MSCs) overexpressing MIF in a rat model of MI. MIF plasmid was transducted in BM-MSCs. Exo were isolated from the supernatants of BM-MSCs and MIF-BM-MSCs, respectively. The morphology of mitochondria in neonatal mice cardiomyocytes (NRCMs) was determined by MitoTracker staining. The apoptosis of NRCMs was examined by deoxynucleotidyl transferase-mediated dUTP nick end-labeling. BM-MSC-exo and MIF-BM-MSC-exo were intramuscularly injected into the peri-infarct region in a rat model of MI. The heart function of rats was assessed by echocardiography. The expression of MIF was greatly enhanced in MIF-BM-MSCs compared with BM-MSCs. Both BM-MSC-exo and MIF-BM-MSC-exo expressed CD63 and CD81. NRCMs treated with MIF-BM-MSC-exo exhibited less mitochondrial fragmentation and cell apoptosis under hypoxia/serum deprivation (H/SD) challenge than those treated with BM-MSC-exo via activating adenosine 5'-monophosphate-activated protein kinase signaling. Moreover, these effects were partially abrogated by Compound C. Injection of BM-MSC-exo or MIF-BM-MSC-exo greatly restored heart function in a rat model of MI. Compared with BM-MSC-exo, injection of MIF-BM-MSC-exo was associated with enhanced heart function, reduced heart remodeling, less cardiomyocyte mitochondrial fragmentation, reactive oxygen species generation, and apoptosis. Our study reveals a new mechanism of MIF-BM-MSC-exo-based therapy for MI and provides a novel strategy for cardiovascular disease treatment.
Exosomes derived from endothelial progenitor cells enhance osteogenesis of mesenchymal stem cells by activating the MAPK dependent pathway
Recent studies have shown that endothelial progenitor cells (EPCs) could enhance osteogenesis of mesenchymal stem cells (MSCs) through multiple paracrine signals. However, the role of EPCs-derived exosomes (EPCs-exos) in osteogenesis has been rarely reported, and little is known regarding their underlying mechanisms. This study attempted to investigate the underlying mechanism by which EPCs-exos promotes osteogenesis of MSCs. EPCs-exos was isolated by supercentrifugation and characterized by western blot, transmission electron microscopy (TEM) and nano particle analysis (NTA). Internalization of EPCs-exos was observed via a laser confocal microscope. The effects of EPCs-exos on the regulation of MSCs biological properties were investigated in vivo and in vitro. The expression of osteogenesis markers and calcium nodule formation was quantified by qRT-PCR, western blotting, alkaline phosphatase (ALP) staining and Alizarin Red staining. Rat critical-sized calvarial bone defects model was used to assess the efficacy of EPCs-exos on bone regeneration. Real-time PCR array and western blotting were performed to explore possible signaling pathways involved in osteogenesis. Results showed that EPCs-exos could be internalized by MSCs, which exhibited greater ALP activity and increased calcium mineral deposition and improved osteogenic markers expression. EPCs-exos combined with MSCs could improve bone regeneration in vivo. These data suggest that EPCs-exos influence the biological function and promote MSCs osteogenic differentiation in vivo and in vitro. Mitogen-activated protein kinase (MAPK) signaling pathway was involved in this process. Activation of the p38MAPK pathway may be the key to enhancing MSCs osteogenic differentiation.