Research Progress on the Osteogenesis-Related Regulatory Mechanisms of Human Umbilical Cord Mesenchymal Stem Cells

Effect of lyophilized exosomes derived from umbilical cord stem cells on chronic anterior cruciate ligament cell injury

BACKGROUND

Facilitating the healing process of injured anterior cruciate ligament (ACL) tissue is crucial for patients to safely return to sports. Stem cell derived exosomes have shown positive effects on enhancing the regeneration of injured tendons/ligaments. However, clinical application of exosomes in terms of storage and pre-assembly is challenging. We hypothesized that lyophilized exosomes derived from human umbilical cord stem cells (hUSC-EX) could enhance the cell activity of chronically injured ACL cells.

MATERIALS AND METHODS

We harvested the 8 weeks injured ACL cells from rabbit under IACUC (No. 110232) approval. The studied exosomes were purified from the culture medium of human umbilical cord stem cells (IRB approval No. A202205014), lyophilized to store, and hydrated for use. We compared exosome treated cells with non-exosome treated cells (control group) from the same rabbits. We examined the cell viability, proliferation, migration capability and gene expression of type I and III collagen, TGFβ, VEGF, and tenogenesis in the 8 weeks injured ACL cells after hUSC-EX treatment.

RESULTS

After hydration, the average size of hUSC-EX was 84.5 ± 70.6 nm, and the cells tested positive for the Alix, TSG101, CD9, CD63, and CD81 proteins but negative for the α-Tubulin protein. After 24 h of treatment, hUSC-EX significantly improved the cell viability, proliferation and migration capability of 8 weeks injured ACL cells compared to that of no exosome treatment group. In addition, the expression of collagen synthesis, TGFβ, VEGF, and tenogenesis gene were all significantly increased in the 8 weeks injured ACL cells after 24 h hUSC-EX delivery.

DISCUSSION

Lyophilized exosomes are easily stored and readily usable after hydration, thereby preserving their characteristic properties. Treatment with lyophilized hUSC-EX improved the activity and gene expression of 8 weeks injured ACL cells.

CONCLUSION

Lyophilized hUSC-EX preserve the characteristics of exosomes and can improve chronically injured (8 weeks) ACL cells. Lyophilized hUSC-EX could serve as effective and safe biomaterials that are ready to use at room temperature to enhance cell activity in patients with partial ACL tears and after remnant preservation ACL reconstruction.

Unveiling the Therapeutic Potential of hUCMSC-Derived EVs in Intervertebral Disc Degeneration through MALAT1/miR-138-5p/SLC7A11 Coexpression Regulation

Intervertebral disc degeneration (IVDD) is a prevalent chronic condition causing spinal pain and functional impairment. This study investigates the role of extracellular vesicles (EVs) derived from human umbilical cord mesenchymal stem cells (hUCMSCs) in regulating IVDD. Using RNA-seq, we analyzed differential expressions of lncRNA and miRNA in nucleus pulposus tissues from various mouse groups. We identified key regulatory molecules, MALAT1 and miRNA-138-5p, which contribute to IVDD. Further experiments demonstrated that MALAT1 can up-regulate SLC7A11 expression by competitively binding to miR-138-5p, forming a MALAT1/miR-138-5p/SLC7A11 coexpression regulatory network. This study elucidates the molecular mechanism by which hUCMSC-derived EVs regulate IVDD and could help develop novel therapeutic strategies for treating this condition. Our findings demonstrate that hUCMSCs-EVs inhibit ferroptosis in nucleus pulposus cells, thereby improving IVDD. These results highlight the therapeutic potential of hUCMSCs-EVs in ameliorating the development of IVDD, offering significant scientific and clinical implications for new treatments.

Human umbilical cord mesenchymal stem cells promote steroid-induced osteonecrosis of the femoral head repair by improving microvascular endothelial cell function

Recently, there has been growing interest in using cell therapy through core decompression (CD) to treat osteonecrosis of the femoral head (ONFH). Our study aimed to investigate the effectiveness and mechanism of human umbilical cord mesenchymal stem cells (hUCMSCs) in treating steroid-induced ONFH. We constructed a steroid-induced ONFH rabbit model as well as dexamethasone (Dex)-treated bone microvascular endothelial cells (BMECs) model of human femoral head. We injected hUCMSCs into the rabbit femoral head via CD. The effects of hUCMSCs on steroid-induced ONFH rabbit model and Dex-treated BMECs were evaluated via micro-CT, microangiography, histology, immunohistochemistry, wound healing, tube formation, and western blotting assay. Furthermore, we conducted single-cell RNA sequencing (scRNA-seq) to examine the characteristics of endothelial cells, the activation of signaling pathways, and inter-cellular communication in ONFH. Our data reveal that hUCMSCs improved the femoral head microstructure and bone repair and promoted angiogenesis in the steroid-induced ONFH rabbit model. Importantly, hUCMSCs improved the migration ability and angioplasty of Dex-treated BMECs by secreting COL6A2 to activate FAK/PI3K/AKT signaling pathway via integrin α1β1.

Stimulated Human Umbilical Cord Mesenchymal Stem Cells Enhance the Osteogenesis and Cranial Bone Regeneration through IL-32 Mediated P38 Signaling Pathway

Objective

Our previous study found that it could significantly increase the expression of IL32 after stimulating the human umbilical cord mesenchymal stem cells (S-HuMSCs). However, its role on the osteogenesis and cranial bone regeneration is still largely unknown. Here, we investigated the possible mechanism of this effect. Material and Methods. A series of experiments, including single-cell sequencing, flow cytometry, quantitative real-time polymerase chain reaction, and western blotting, were carried out to evaluate the characteristic and adipogenic-osteogenic differentiation potential of IL-32 overexpression HuMSCs (IL-32highHuMSCs) through mediating the P38 signaling pathway. Moreover, a rat skull bone defect model was established and treated by directly injecting the IL-32highHuMSCs to conduct its role on the cranial bone regeneration.

Results

In total, it found that compared to HuMSCs, IL32 was significantly increased and promoted the osteogenic differentiation (lower expressions of PPARγ, Adiponectin, and C/EBPα, and increased expressions of RUNX2, ALP, BMP2, OPN, SP7, OCN, and DLX5) in the S-HuMSCs (P < 0.05). Meanwhile, the enhanced osteogenic differentiation of HuMSCs was recovered by IL-32 overexpression (IL-32highHuMSCs) through activating the P38 signaling pathway, like as the S-HuMSCs (P < 0.05). However, the osteogenic differentiation potential of IL-32highHuMSCs was significantly reversed by the P38 signaling pathway inhibitor SB203580 (P < 0.05). Additionally, the HuMSCs, S-HuMSCs, and IL-32highHuMSCs all presented adipogenic-osteogenic differentiation potential, with higher levels of CD73, CD90, and CD105, and lower CD14, CD34, and CD45 (P > 0.05). Furthermore, these findings were confirmed by the rat skull bone defect model, in which the cranial bone regeneration was more pronounced in the IL-32highHuMSCs treated group compared to those in the HuMSCs group, with higher expressions of RUNX2, ALP, BMP2, and DLX5 (P < 0.05).

Conclusion

We have confirmed that S-HuMSCs can enhance the osteogenesis and cranial bone regeneration through promoting IL-32-mediated P38 signaling pathway, which is proved that IL-32 may be a therapeutic target, or a biomarker for the treatment of cranial bone injuries.

Engineered stem cell-based strategy: A new paradigm of next-generation stem cell product in regenerative medicine

Stem cells have garnered significant attention in regenerative medicine owing to their abilities of multi-directional differentiation and self-renewal. Despite these encouraging results, the market for stem cell products yields limited, which is largely due to the challenges faced to the safety and viability of stem cells in vivo. Besides, the fate of cells re-infusion into the body unknown is also a major obstacle to stem cell therapy. Actually, both the functional protection and the fate tracking of stem cells are essential in tissue homeostasis, repair, and regeneration. Recent studies have utilized cell engineering techniques to modify stem cells for enhancing their treatment efficiency or imparting them with novel biological capabilities, in which advances demonstrate the immense potential of engineered cell therapy. In this review, we proposed that the "engineered stem cells" are expected to represent the next generation of stem cell therapies and reviewed recent progress in this area. We also discussed potential applications of engineered stem cells and highlighted the most common challenges that must be addressed. Overall, this review has important guiding significance for the future design of new paradigms of stem cell products to improve their therapeutic efficacy.