LncRNA LYPLAL1-AS1 rejuvenates human adipose-derived mesenchymal stem cell senescence via transcriptional MIRLET7B inactivation

Background

Mesenchymal stem cell (MSC) senescence is a phenotype of aging. Long noncoding RNAs (lncRNAs) are emerging as potential key regulators of senescence. However, the role of lncRNAs in MSC senescence remains largely unknown.

Results

We performed transcriptome analysis in senescent human adipose-derived MSCs (hADSCs) and identified that the lncRNA LYPLAL1 antisense RNA1 (LYPLAL1-AS1) was significantly downregulated in senescent hADSCs. LYPLAL1-AS1 expression in peripheral blood was lower in middle-aged healthy donors than in young adult donors, and correlated negatively with age. Knockdown of LYPLAL1-AS1 accelerated hADSC senescence, while LYPLAL1-AS1 overexpression attenuated it. Chromatin isolation by RNA purification (ChIRP) sequencing indicated that LYPLAL1-AS1 bound to the MIRLET7B promoter region and suppressed its transcription activity, as demonstrated by dual-luciferase assay. miR-let-7b, the transcript of MIRLET7B, was upregulated during hADSC senescence and was regulated by LYPLAL1-AS1. Furthermore, miR-let-7b mimics promoted hADSC senescence, while the inhibitors repressed it. Finally, LYPLAL1-AS1 overexpression reversed miR-let-7b-induced hADSC senescence.

Conclusions

Our data demonstrate that LYPLAL1-AS1 rejuvenates hADSCs through the transcriptional inhibition of MIRLET7B. Our work provides new insights into the mechanism of MSC senescence and indicates lncRNA LYPLAL1-AS1 and miR-let-7b as potential therapeutic targets in aging.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13578-022-00782-x.

Dysregulated Expression of Apoptosis-Associated Genes and MicroRNAs and Their Involvement in Gastric Carcinogenesis

PURPOSE

Analyze the expression of caspase-9, Smac/DIABLO, XIAP, let-7a, and let-7b in patients with normal gastric tissue, chronic gastritis, and gastric adenocarcinoma.

METHODS

The expression of caspase-9, Smac/DIABLO, XIAP, let-7a, and let-7b by qRT-PCR was analyzed in 158 samples from 53 patients with normal gastric mucosa, 86 with chronic gastritis, and 19 with gastric cancer.

RESULTS

The comparison between the gastric cancer and the control group revealed a decreased expression of caspase-9 in gastric cancer tissues; considering the Helicobacter pylor presence, comparable results were revealed. Smac/DIABLO was increased in gastric cancer cells, while XIAP demonstrated no significant difference in the gene expression. The microRNA analysis revealed a decreased expression of let-7a and let-7b in samples positive to H. pylori infection and in gastric cancer group, regardless of the presence of the bacterium.

CONCLUSION

Our study provided some evidence of low activity of the intrinsic apoptosis pathway, as well as the influence of H. pylori on let-7a and let-7b expression.

miR-let-7b and miR-let-7c suppress tumourigenesis of human mucosal melanoma and enhance the sensitivity to chemotherapy

Background

Mucosal melanoma with poor prognosis is a common histopathologic subtype of melanoma among Chinese and other Asian peoples. Regulated microRNAs (miRNAs) have been reported as oncogenes or tumour suppressors in melanoma. However, the roles of specific miRNAs in mucosal melanoma remain largely unknown. Here, we aimed to assess the biological functions, molecular mechanisms and clinical potential of miR-let-7b and miR-let-7c in mucosal melanoma.

Methods

The expression of miR-let-7b and miR-let-7c in mucosal melanoma was determined by quantitative polymerase chain reaction (qPCR). Cutoff scores for miR-let-7b and miR-let-7c expressions were calculated through receiver operating characteristic (ROC) curve analysis in 106 mucosal melanoma patients according to recurrence. Correlations of miR-let-7b and miR-let-7c expression with clinicopathological characteristics, disease-free survival (DFS) and clinical benefits after treatment were then statistically analysed. The biological functions and molecular mechanisms of miR-let-7b and miR-let-7c were studied in vitro and in vivo.

Results

The expression of miR-let-7b and miR-let-7c was decreased in 94 cases (88.7%) and 89 cases (84.0%) of 106 mucosal melanoma patients compared with mucosal nevi. A correlation was observed between the expression of miR-let-7b, miR-let-7c and DFS after surgery. In addition, overexpression of miR-let-7b or miR-let-7c inhibited mucosal melanoma cell growth, migration, invasion and metastasis and induced cell apoptosis and cell cycle arrest in vitro and in vivo. Mechanistically, miR-let-7b and miR-let-7c directly targeted metadherin (MTDH) and calumenin (CALU) and suppressed phospho-ERK in mucosal melanoma cells. MTDH and CALU reversed the partial function of miR-let-7b and miR-let-7c in vitro. Furthermore, progression-free survival (PFS) of mucosal melanoma patients upon temozolomide-based and paclitaxel-based chemotherapy was related to miR-let-7b and miR-let-7c expression. Overexpression of miR-let-7b or miR-let-7c in patient-derived xenograft (PDX) models and certain mucosal melanoma cells had better growth inhibition after temozolomide and paclitaxel treatment. MTDH reversed the sensitivity of miR-let-7b and miR-let-7c to paclitaxel in vitro.

Conclusions

Our results suggested that miR-let-7b and miR-let-7c inhibited the recurrence of mucosal melanoma through inhibiting cell growth, migration, invasion and metastasis, inducing cell apoptosis and cell cycle arrest by targeting MTDH and CALU. In addition, miR-let-7b and miR-let-7c increased sensitivity to chemotherapeutic agents by targeting MTDH.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1190-3) contains supplementary material, which is available to authorized users.

Ultrasound microbubbles mediated miR-let-7b delivery into CD133+ ovarian cancer stem cells

Ovarian cancer stem cells (OCSCs) are considered the reason for ovarian cancer’s emergence and recurrence. Ultrasound-targetted microbubble destruction (UTMD), a non-vial, safe, and promising delivery method for miRNA, is reported to transfect cancer stem cells (CSCs). In the present study, we investigated to transfect miR-let-7b into OCSCs using UTMD. The CD133⁺ OCSCs, accounted for only 0.1% of ovarian cancer cell line A2780, were separated by flow cytometry, and the CSC characteristics of CD133⁺ OCSCs have been proved by spheroid formation and self-renewal assay. The miR-let-7b transfection efficiency using UTMD was significantly higher than other groups except lipofectamine group through flow cytometry. The cell viability of all groups decreased after transfection, and the late apoptosis rate of CD133⁺ OCSCs after miR-let7b transfection induced by UTMD was 2.62%, while that of non-treated cells was 0.02% (P<0.05). Furthermore, the Western blot results demonstrated that the stem cells surface marker of CD133 expression has decreased. Therefore, our results indicated that UTMD-mediated miRNA delivery could be a promising platform for CSC therapy.

Dexmedetomidine Protects PC12 Cells from Lidocaine-Induced Cytotoxicity Through Downregulation of COL3A1 Mediated by miR-let-7b

Safety concerns of some local anesthetics, such as lidocaine, have been raised in recent years due to potential neurological impairment. Dexmedetomidine may protect humans from neurotoxicity, and miR-let-7b is activated by nerve injury; however, the roles of miR-let-7b and its target gene in lidocaine-induced cytotoxicity are not well known. Through bioinformatics and a luciferase reporter assay, COL3A1 was suggested as a direct target gene of miR-let-7b. Here, we confirmed by measuring mRNA and protein levels that miR-let-7b was downregulated and COL3A1 was upregulated in lidocaine-treated cells, an observation that was reversed by dexmedetomidine. Similar to miR-let-7b mimics or knockdown of COL3A1, dexmedetomidine treatment reduced the expression of COL3A1, suppressed cell apoptosis and cell migration/invasion ability, and induced cell cycle progression and cell proliferation in PC12 cells, effects that were reversed by the miR-let-7b inhibitor. Meanwhile, proteins involved in cell apoptosis, such as Bcl2 and caspase 3, were impacted as well. Taken together, dexmedetomidine may protect PC12 cells from lidocaine-induced cytotoxicity through miR-let-7b and COL3A1, while also increasing Bcl2 and inhibiting caspase 3. Therefore, miR-let-7b and COL3A1 might play critical roles in neuronal injury, and they are potential therapeutic targets.