Bone Marrow-Derived Mesenchymal Stem Cells Promoted Cutaneous Wound Healing by Regulating Keratinocyte Migration via ß2-Adrenergic Receptor Signaling.

Mesenchymal stem cells (MSCs) play an important role in cutaneous wound healing; however, the functional mechanisms involved in the healing process are poorly understood. A series of studies indicate that keratinocytes that migrate into the wound bed rely on an epithelial-mesenchymal transition (EMT)-like process to initiate re-epithelialization. We therefore examined whether bone marrow-derived MSCs (BMSCs) could affect biological behavior and induce EMT-like characteristics in the human epidermal keratinocytes (HEKs) and in the immortalized human keratinocyte cell line HaCaT cells, and we investigated the signaling pathways of BMSC-mediated phenotypic changes. By assessing the expression of EMT-related markers including E-cadherin, α-SMA, and Snail family transcription factors by ß2-adrenergic receptor (ß2-AR) blockage using ICI-118,551, a ß2-AR selective antagonist, or ß2-AR small interfering RNA (siRNA), we showed an involvement of ß2-AR signaling in the induction of EMT-like alterations in human keratinocytes in vitro. ß2-AR signaling also affected collective and individual cell migration in human keratinocyte cell lines, which was attenuated by administration of ICI-118,551. Treating the cells with BMSC-conditioned media (BMSC-CM) not only recapitulated the effect of isoproterenol (ISO) on cell migration but also induced the expression of ß2-AR and a panel of proteins associated with mesenchymal phenotype in HEKs and HaCaT cells. Similarly, a blockade of the ß2-AR by either ICI-118,551 or ß2-AR siRNAs reversed both responses of the epidermal keratinocyte cell lines relative to BMSC-CM exposure. These results were further verified in our vivo findings and indicated that the exogenous application of MSCs promoted cutaneous wound healing and endowed the keratinocytes surrounding the wound area with an increased migratory phenotype through activation of ß2-AR signaling. Our findings suggest a biochemical mechanism underlying the function of MSCs in wound re-epithelization, which provides a reliable theoretical basis for the wide application of MSCs in the treatment of chronic wounds.

Relationship between histological mixed-type early gastric cancer and lymph node metastasis: A systematic review and meta-analysis.

The clinicopathological features of early gastric cancer (EGC) with mixed-type histology (differentiated and undifferentiated) are incompletely understood, and the capacity of endoscopic submucosal dissection (ESD) to treat mixed-type cancer remains controversial. This systematic review analyzed the rate of lymph node metastasis (LNM) in mixed-type EGC. We gathered articles published up to February 21, 2021, that analyzed the relationship between LNM and mixed-type EGC from Embase, PubMed, and Web of Science. The primary outcome was the LNM rate associated with different histological types of EGC, and the secondary outcomes were the odds ratios (ORs) for LNM risk factors among EGC patients. From the 24 studies included in this meta-analysis, the overall rate of LNM in predominantly differentiated mixed-type (MD) EGC was 12%, whereas the LNM rate in predominantly undifferentiated mixed-type (MU) EGC was 22%. We further divided these studies into 2 groups according to the depth of invasion. In mixed-type mucosal EGC, the pooled LNM rate was 15%; in submucosal EGC, the rate was 33% for MU, which was higher than the rates for pure types (pure differentiated type, 13%; pure undifferentiated type, 21%; p<0.05). The LNM rate of MD was 20%, it was higher than those of the pure differentiated type and nearly the same as pure undifferentiated type. Other pooled statistics showed that submucosal invasion, pure undifferentiated EGC, and mixed-type EGC were independent risk factors for LNM. This meta-analysis showed that MD submucosal EGC has a high rate of LNM and is highly correlated with LNM; thus, the management of MD EGC as purely differentiated EGC according to the indications for ESD is inappropriate, and the mixed type should be added as a parameter in these indications.

Molecular subtype identification and predictive power of N6-methyladenosine regulator in unexplained recurrent pregnancy loss.

The etiology of recurrent pregnancy loss (RPL) is complicated and effective clinical preventive measures are lacking. Identifying biomarkers for RPL has been challenging, and to date, little is known about the role of N6-methyladenosine (m6A) regulators in RPL. Expression data for m6A regulators in 29 patients with RPL and 29 healthy controls were downloaded from the Gene Expression Omnibus (GEO) database. To establish a diagnostic model for unexplained RPL, differential gene expression analysis was conducting for 36 m6A regulators using least absolute shrinkage and selection operator (LASSO) regression. Unsupervised cluster analysis was conducted on hub genes, and probable mechanisms were explored using gene set enrichment analysis (GSEA) and gene ontology (GO) analysis. Correlations between m6A-related differentially expressed genes and immune infiltration were analyzed using single-sample GSEA. A total of 18 m6A regulators showed significant differences in expression in RPL: 10 were upregulated and eight were downregulated. Fifteen m6A regulators were integrated and used to construct a diagnostic model for RPL that had good predictive efficiency and robustness in differentiating RPL from control samples, with an overall area under the curve (AUC) value of 0.994. Crosstalk was identified between 10 hub genes, miRNAs, and transcription factors (TFs). For example, YTHDF2 was targeted by mir-1-3p and interacted with embryonic development-related TFs such as FOXA1 and GATA2. YTHDF2 was also positively correlated with METTL14 (r = 0.5983, p < 0.001). Two RPL subtypes (Cluster-1 and Cluster-2) with distinct hub gene signatures were identified. GSEA and GO analysis revealed that the differentially expressed genes were mainly associated with immune processes and cell cycle signaling pathway (normalized enrichment score, NES = -1.626, p < 0.001). Immune infiltration was significantly higher in Cluster-1 than in Cluster-2 (p < 0.01). In conclusion, we demonstrated that m6A modification plays a critical role in RPL. We also developed and validated a diagnostic model for RPL prediction based on m6A regulators. Finally, we identified two distinct RPL subtypes with different biological processes and immune statuses.

Targeting ectodysplasin promotor by CRISPR/dCas9-effector effectively induces the reprogramming of human bone marrow-derived mesenchymal stem cells into sweat gland-like cells.

BACKGROUND: Patients with a deep burn injury are characterized by losing the function of perspiration and being unable to regenerate the sweat glands. Because of their easy accession, multipotency, and lower immunogenicity, bone marrow-derived mesenchymal stem cells (BM-MSCs) represent as an ideal biological source for cell therapy. The aim of this study was to identify whether targeting the promotor of ectodysplasin (EDA) by CRISPR/dCas9-effector (dCas9-E) could induce the BM-MSCs to differentiate into sweat gland-like cells (SGCs). METHODS: Activation of EDA transcription in BM-MSCs was attained by transfection of naive BM-MSCs with the lenti-CRISPR/dCas9-effector and single-guide RNAs (sgRNAs). The impact of dCas9-E BM-MSCs on the formation of SGCs and repair of burn injury was identified and evaluated both in vitro and in a mouse model. RESULTS: After transfection with sgRNA-guided dCas9-E, the BM-MSCs acquired significantly higher transcription and expression of EDA by doxycycline (Dox) induction. Intriguingly, the specific markers (CEA, CK7, CK14, and CK19) of sweat glands were also positive in the transfected BM-MSCs, suggesting that EDA plays a critical role in promoting BM-MSC differentiation into sweat glands. Furthermore, when the dCas9-E BM-MSCs with Dox induction were implanted into a wound in a laboratory animal model, iodine-starch perspiration tests revealed that the treated paws were positive for perspiration, while the paws treated with saline showed a negative manifestation. For the regulatory mechanism, the expression of downstream genes of NF-κB (Shh and cyclin D1) was also enhanced accordingly. CONCLUSIONS: These results suggest that EDA is a pivotal factor for sweat gland regeneration from BM-MSCs and may also offer a new approach for destroyed sweat glands and extensive deep burns.