A therapeutic role of exosomal lncRNA H19 from adipose mesenchymal stem cells in cutaneous wound healing by triggering macrophage M2 polarization.

Emerging evidence has figured out that adipose mesenchymal stem cells (ADSCs) promote wound healing. Exosomes, which act as main paracrine factors and contains various protein, lncRNA, and miRNAs, play a critical role in wound healing. Nevertheless, the mechanism remains to be elucidated. This study aims to identify the underlying mechanism of ADSCs-derived exosome (ADSCs-exos)-mediated wound healing. ADSCs-exos were characterized using the transmission electron microscope, dynamic light scattering, and western blot. ELISA, RT-qPCR, flow cytometry, western blot, CCK-8 assay, transwell assay and tube formation were employed to validate the actions of ADSCs-exos harboring H19 in cell polarization, proliferation, migration and angiogenesis. The regulatory axis among H19, miR-130b-3p and PPARγ or STAT3 was confirmed by RNA pull-down, RIP assay and dual-luciferase reporter assays. ADSCs-exos harboring H19 promoted macrophage M2 polarization, thereby enhancing fibroblast proliferation, migration and endothelial cell angiogenesis. However, their promotive effects were disrupted within H19 depletion in ADSCs-exos. Additionally, miR-130b-3p, directly targeting PPARγ or STAT3, was identified to be a downstream effector to participate in H19-mediated biological effects. Moreover, ADSCs-exos carrying H19 modulated cutaneous wound healing via H19/miR-130b-3p -mediated macrophage M2 polarization in vivo. Collectively, ADSCs-derived exosomal H19 accelerates cutaneous wound healing via the miR-130b-3p/PPARγ/STAT3 axis, indicating potential therapeutic strategies for the treatment of wound healing.

Li B ，Qian L ，Pi L ，Meng X ... -  《-》

Adipose mesenchymal stem cell-derived exosomes accelerate skin wound healing via the lncRNA H19/miR-19b/SOX9 axis.

It has been reported that adipose mesenchymal stem cells (ADSCs) accelerate wound healing. Moreover, exosomes, which serve as paracrine factors, play a vital role in wound healing. However, the mechanism remains unclear. This research aimed to determine the roles of exosomes derived from ADSCs (ADSC-Exos) in wound skin tissue repair. Flow cytometry and electron microscopy were carried out to identify ADSCs and ADSC-Exos, respectively; RT-qPCR was performed to assess the lncRNA H19 (H19), microRNA19b (miR-19b) and SRY-related high-mobility-group box 9 (SOX9) levels; Western blotting was carried out to evaluate collagen and β-catenin expression; CCK-8, scratch and transwell assays were conducted to evaluate human skin fibroblast (HSF) cell proliferation, migration and invasion, respectively; the potential binding sites between H19 and miR-19b, miR-19b and SOX9 were detected by dual-luciferase reporter gene assay and RIP assay; and H&E staining was conducted to observe skin wound tissues. ADSC-Exos accelerated the proliferation, migration and invasion of HSF cells via H19. H19 acts as a molecular sponge towards miR-19b, which targets SOX9. ADSC-Exos inhibited miR-19b expression via H19, resulting in accelerated HSF proliferation, migration and invasion. ADSC-Exos upregulated SOX9 to activate the Wnt/β-catenin pathway, resulting in accelerated HSF cell proliferation, migration and invasion, and ADSC-Exos promoted skin wound healing via H19 in mice.The high expression of H19 in ADSC-Exos may upregulate SOX9 expression via miR-19b to accelerate wound healing of skin tissues. Our study may provide novel perspectives for therapy to accelerate skin wound healing.

Qian L ，Pi L ，Fang BR ，Meng XX ... -  《-》

Hypoxic adipose stem cell-derived exosomes carrying high-abundant USP22 facilitate cutaneous wound healing through stabilizing HIF-1α and upregulating lncRNA H19.

Hypoxic preconditioning has been recognized as a promotive factor for accelerating cutaneous wound healing. Our previous study uncovered that exosomal lncRNA H19, derived from adipose-derived stem cells (ADSCs), plays a crucial role in orchestrating cutaneous wound healing. Herein, we aimed to explore whether there is a connection between hypoxia and ADSC-derived exosomes (ADSCs-exos) in cutaneous wound healing. Exosomes extracted from ADSCs under normoxic and hypoxic conditions were identified using transmission electron microscope (TEM) and particle size analysis. The effects of ADSCs-exos on the proliferation, migration, and angiogenesis of human umbilical vein endothelial cells (HUVECs) were evaluated by CCK-8, EdU, wound healing, and tube formation assays. Expression patterns of H19, HIF-1α, and USP22 were measured. Co-immunoprecipitation, chromatin immunoprecipitation, ubiquitination, and luciferase reporter assays were conducted to confirm the USP22/HIF-1α/H19 axis, which was further validated in a mice model of skin wound. Exosomes extracted from hypoxia-treated ADSCs (termed as H-ADSCs-exos) significantly increased cell proliferation, migration, and angiogenesis in H2O2-exposed HUVECs, and promoted cutaneous wound healing in vivo. Moreover, H-ADSCs and H-ADSCs-exos, which exhibited higher levels of H19, were found to be transcriptionally activated by HIF-1α. Mechanically, H-ADSCs carrying USP22 accounted for deubiquitinating and stabilizing HIF-1α. Additionally, H-ADSCs-exos improved cell proliferation, migration, and angiogenesis in H2O2-triggered HUVECs by activating USP22/HIF-1α axis and promoting H19 expression, which may provide a new clue for the clinical treatment of cutaneous wound healing.

Qian L ，Li B ，Pi L ，Fang B ，Meng X ... -  《-》

Exosomes Derived from E2F1(-/-) Adipose-Derived Stem Cells Promote Skin Wound Healing via miR-130b-5p/TGFBR3 Axis.

Skin wound is a widespread health problem and brings extraordinary burdens to patients. Exosomes derived from adipose-derived stem cells (ADSC-Exos) are considered promising strategies for repairing skin wounds. E2F1 is a member of the E2F family of transcription factors involved in cell growth and apoptosis. E2F1 deficiency in mice enhances wound healing by improving collagen deposition and angiogenesis. Additionally, E2F1 can regulate the transcription and paracrine activity of multiple miRNAs, which will inevitably reshape the paracrine expression profile of ADSC-Exos. This study aimed to investigate the impact of transcription factor E2F1 deficiency on the functions of ADSC-Exos in promoting wound healing. First, we obtained ADSCs from subcutaneous adipose tissues of WT and E2F1-/- C57BL/6 mice and separated their exosomes, denoted as ADSCWT-Exos and ADSCE2F1-/--Exos. The wound healing effects of ADSCWT-Exos and ADSCE2F1-/--Exos in full-thickness skin wound models were investigated by wound images, H&E staining, and immunohistochemical staining. For the in vitro study, the abilities of ADSCWT-Exos and ADSCE2F1-/--Exos to promote cell activities, collagen formation, and angiogenesis were evaluated. The potential mechanism by which ADSCE2F1-/--Exos promote wound healing was determined by miRNA sequencing, ChIP‒qPCR, and dual-luciferase assays. ADSCE2F1-/--Exos accelerated wound healing by promoting collagen formation and angiogenesis. As a result, compared with the lower wound healing rate of 30.5% within 7 days in the control group and 42.3% in the ADSCWT-Exo group, ADSCE2F1-/--Exos significantly increased the wound healing rate to 72.5%. In vitro, ADSCE2F1-/--Exos activated the function of fibroblasts and vascular endothelial cells. The loss of E2F1 promoted miR-130b-5p expression in ADSCE2F1-/--Exos through transcriptional regulation. MiRNA high-throughput sequencing identified 12 differently expressed miRNAs between ADSCE2F1-/- and ADSCWT. ADSCE2F1-/--Exos enhanced fibroblast activities via the miR-130b-5p/TGFBR3 axis and TGF-β activation. Our results indicated that ADSCE2F1-/--Exos effectively promoted wound healing by regulating the miR-130b-5p/TGFBR3 axis, thus providing a novel strategy of gene-engineered stem cell exosomes for accelerating wound healing.

Yu H ，Wu Y ，Zhang B ，Xiong M ，Yi Y ，Zhang Q ，Wu M ... -  《International Journal of Nanomedicine》

Exosome-mediated transfer of lncRNA HCG18 promotes M2 macrophage polarization in gastric cancer.

Gastric cancer (GC) derived exosomes (Exos) aggravate GC development by facilitating M2 macrophage polarization and long non-coding RNA (lncRNA) HCG18 was highly expressed in GC. This study aimed to investigate whether the exosomal lncRNA HCG18 regulated the M2 macrophage polarization in GC and the possible mechanism. The isolated GC cells (GCCs)-Exos were identified using transmission electron microscopy, Nanoparticle Tracking Analysis and Western blot. The GCCs-Exos function was verified by enzyme-linked immunosorbent assay and flow cytometry. Meanwhile, the exosomal lncRNA HCG18 function was determined using thein vitro assays. Furthermore, the underlying mechanism of the exosomal lncRNA HCG18 that regulated M2 macrophage polarization in GC was investigated using dual-luciferase reporter gene assay and RNA pull-down. After the validation of GCCs-Exos, the GCCs-Exos facilitated the M2 macrophage polarization. The in vitro assays confirmed that the exosomal lncRNA HCG18 positively regulated the M2 macrophage polarization. Mechanistically, lncRNA HCG18 bound to miR-875-3p, miR-875-3p bound to KLF4. Furthermore, GCCs-exosomal lncRNA HCG18 elevated the KLF4 expression by decreasing miR-875-3p in macrophages to facilitate M2 macrophage polarization, thus alleviating GC. The in vivo assays clarified that the GCCs-exosomal lncRNA HCG18 restrained the tumor growth of GC induced by M2 macrophages. GCCs-exosomal lncRNA HCG18 elevated KLF4 expression by decreasing miR-875-3p in macrophages to facilitate the M2 macrophage polarization.

Xin L ，Wu Y ，Liu C ，Zeng F ，Wang JL ，Wu DZ ，Wu JP ，Yue ZQ ，Gan JH ，Lu H ，Yuan YW ，Zhou LQ ... -  《-》