miR-181b-5p promotes proliferation and inhibits apoptosis of hypertrophic scar fibroblasts through regulating the MEK/ERK/p21 pathway

Administration of a combination of COX-2/TGF-β1 siRNAs induces hypertrophic scar fibroblast apoptosis through a TP53 mediated caspase pathway

Hypertrophic scar (HTS) formation is a pathological fibrotic skin disease, with no satisfactory treatments available currently. Inducing apoptosis of HTS-derived fibroblasts (HSFs) are becoming promising approaches. In this research, we aim to improve the technology with co-delivery COX-2 and TGF-β1 siRNAs and further investigate the underlying mechanism. Firstly, the HSFs were transfected with 1 µg/ml COX-2 and/or TGF-β1 siRNAs, and proved that the apoptosis of HSFs was greater induced by COX-2/TGF-β1 siRNAs than either COX-2 or TGF-β1 siRNA alone by flow cytometry. To investigate the impact of co-silencing TGF-β1 and COX-2 mRNA expression in vivo, we established HTSs model in rat tails. Our results confirmed that co-silencing of TGF-β1 and COX-2 mRNA expression could significantly alleviate the HTS formation in vivo. Furthermore, we explored the potential molecular mechanism and revealed that the protein levels of TP53, Bcl-2 and Caspase-3 were downregulated while Bax and Cleaved Caspase-3 were upregulated in the COX-2/TGF-β1 siRNA groups compared with HKP group. Taken together, our results demonstrated that simultaneous silencing of COX-2 and TGF-β1 expression by siRNAs induced HSF apoptosis through a TP53 mediated caspase pathway. Therefore, COX-2/TGF-β1 siRNAs might serve as a novel and effective therapeutic alternative for HTSs treatments.

OncomiR-181a promotes carcinogenesis by repressing the extracellular matrix proteoglycan decorin in hepatocellular carcinoma

BACKGROUND

Proteoglycans are important tumor microenvironment extracellular matrix components. The regulation of key proteoglycans, such as decorin (DCN), by miRNAs has drawn attention since they have surfaced as novel therapeutic targets in cancer. Accordingly, this study aimed at identifying the impact of miR-181a in liver cancer and its regulatory role on the extracellular matrix proteoglycan, DCN, and hence on downstream oncogenes and tumor suppressor genes.

RESULTS

DCN was under-expressed in 22 cirrhotic and HCC liver tissues compared to that in 11 healthy tissues of liver transplantation donors. Conversely, miR-181a was over-expressed in HCC liver tissues compared to that in healthy liver tissues. In silico analysis predicted that DCN 3'UTR harbors two high-score oncomiR-181a binding regions. This was validated by pmiRGLO luciferase reporter assay. Ectopic miR-181a expression into HuH-7 cells repressed the transcript and protein levels of DCN as assessed fluorometrically and by western blotting. DCN siRNAs showed similar results to miR-181a, where they both enhanced the cellular viability, proliferation, and clonogenicity. They also increased Myc and E2F and decreased p53 and Rb signaling as assessed using reporter vectors harboring p53, Rb, Myc, and E2F response elements. Our findings demonstrated that miR-181a directly downregulated the expression of its direct downstream target DCN, which in turn affected downstream targets related to cellular proliferation and apoptosis.

CONCLUSION

To our knowledge, this is the first study to unveil the direct targeting of DCN by oncomiR-181a. We also highlighted that miR-181a affects targets related to cellular proliferation in HCC which may be partly mediated through inhibition of DCN transcription. Thus, miR-181a could be a promising biomarker for the early detection and monitoring of liver cancer progression. This would pave the way for the future targeting of the oncomiR-181a as a therapeutic approach in liver cancer, where miR-181a-based therapy approach could be potentially combined with chemotherapy and immunotherapy for the management of liver cancer.

Exosomes and microRNAs: insights into their roles in thermal-induced skin injury, wound healing and scarring

A burn is a type of injury to the skin or other tissues caused by heat, chemicals, electricity, sunlight, or radiation. Burn injuries have been proven to have the potential for long-term detrimental effects on the human body. The conventional therapeutic approaches are not able to effectively and easily heal these burn wounds completely. The main potential drawbacks of these treatments include hypertrophic scarring, contracture, infection, necrosis, allergic reactions, prolonged healing times, and unsatisfactory cosmetic results. The existence of these drawbacks and limitations in current treatment approaches necessitates the need to search for and develop better, more efficient therapies. The regenerative potential of microRNAs (miRNAs) and the exosomal miRNAs derived from various cell types, especially stem cells, offer advantages that outweigh traditional burn wound healing treatment procedures. The use of multiple types of stem cells is gaining interest due to their improved healing efficiency for various applications. Stem cells have several key distinguishing characteristics, including the ability to promote more effective and rapid healing of burn wounds, reduced inflammation levels at the wound site, and less scar tissue formation and fibrosis. In this review, we have discussed the stages of wound healing, the role of exosomes and miRNAs in improving thermal-induced wounds, and the impact of miRNAs in preventing the formation of hypertrophic scars. Research studies, pre-clinical and clinical, on the use of different cell-derived exosomal miRNAs and miRNAs for the treatment of thermal burns have been documented from the year 2000 up to the current time. Studies show that the use of different cell-derived exosomal miRNAs and miRNAs can improve the healing of burn wounds. The migration of exosomal miRNAs to the site of a wound leads to inhibition of apoptosis, induction of autophagy, re-epithelialization, granulation, regeneration of skin appendages, and angiogenesis. In conclusion, this study underscores the importance of integrating miRNA and exosome research into treatment strategies for burn injuries, paving the way for novel therapeutic approaches that could significantly improve patient outcomes and recovery times.

Updates on the role of epigenetics in familial mediterranean fever (FMF)

Familial Mediterranean Fever (FMF) is an autosomal recessive autoinflammatory disease caused by mutations in the MEFV (MEditerranean FeVer) gene that affects people originating from the Mediterranean Sea. The high variability in severity and clinical manifestations observed not only between ethnic groups but also between and within families is mainly related to MEFV allelic heterogeneity and to some modifying genes. In addition to the genetic factors underlying FMF, the environment plays a significant role in the development and manifestation of this disease through various epigenetic mechanisms, including DNA methylation, histone modification, and noncoding RNAs. Indeed, epigenetic events have been identified as an important pathophysiological determinant of FMF and co-factors shaping the clinical picture and outcome of the disease. Therefore, it is essential to better understand the contribution of epigenetic factors to autoinflammatory diseases, namely, FMF, to improve disease prognosis and potentially develop effective targeted therapies. In this review, we highlight the latest updates on the role of epigenetics in FMF.

Lipid Deposition and Progesterone Synthesis Are Increased by miR-181b-5p through RAP1B/ERK1/2 Pathway in Chicken Granulosa Cells

Steroid hormones secreted by granulosa cells are essential for maintaining normal development of chicken follicles. Our previous sequencing data indicated that miR-181b-5p and RAS-related protein 1B (RAP1B) appeared to function in chicken granulosa cells, which was further explored in this study. The results suggested that miR-181b-5p facilitated the aggregation of lipid droplets and the synthesis of progesterone. In contrast, RAP1B astricted lipid deposition and progesterone secretion. Cotransfection of the RAP1B overexpression vector with miR-181b-5p mimic eliminated the promoting effect of miR-181b-5p. Dual-luciferase reporter assay confirmed that miR-181b-5p bound directly to the 3' untranslated region (3' UTR) of RAP1B. We also found that miR-181b-5p and RAP1B reduced and enhanced the phosphorylation levels of extracellular signal-regulated kinases 1 and 2 (ERK1/2), respectively. The application of ERK1/2 activators and inhibitors demonstrated that ERK1/2 is a negative regulator of lipid deposition and progesterone synthesis. In conclusion, we revealed that miR-181b-5p accelerated lipid deposition and progesterone synthesis through the RAP1B/ERK1/2 pathway in chicken granulosa cells. miR-181b-5p and RAP1B may serve as new biomarkers in breeding to improve chicken reproductive performance and prevent ovary-related diseases.

[Research advances on the role and mechanism of microRNA in hypertrophic scar]

Hypertrophic scar (HS) affects the function and beauty of patients, and brings a heavy psychological burden to patients. However, the specific pathogenesis mechanism of HS in molecular biology level is not yet clear, and this disease is still one of the clinical diseases difficult to prevent and cure. MicroRNA (miR) is a family of single-stranded endogenous noncoding RNAs that can regulate gene expression. The abnormal transcription of miR in hypertrophic scar fibroblasts can affect the transduction and expression of downstream signal pathway or protein, and the exploration of miR and its downstream signal pathway and protein helps deeply understand the occurrence and development mechanism of scar hyperplasia. This article summarized and analyzed how miR and multiple signal pathways involve in the formation and development of HS in recent years, and further outlined the interaction between miR and target genes in HS.

Extracellular vesicles derived from host and gut microbiota as promising nanocarriers for targeted therapy in osteoporosis and osteoarthritis

Osteoporosis (OP), a systemic bone disease that causes structural bone loss and bone mass loss, is often associated with fragility fractures. Extracellular vesicles (EVs) generated by mammalian and gut bacteria have recently been identified as important mediators in the intercellular signaling pathway that may play a crucial role in microbiota-host communication. EVs are tiny membrane-bound vesicles, which range in size from 20 to 400 nm. They carry a variety of biologically active substances across intra- and intercellular space. These EVs have developed as a promising research area for the treatment of OP because of their nanosized architecture, enhanced biocompatibility, reduced toxicity, drug loading capacity, ease of customization, and industrialization. This review describes the latest development of EVs derived from mammals and bacteria, including their internalization, isolation, biogenesis, classifications, topologies, and compositions. Additionally, breakthroughs in chemical sciences and the distinctive biological features of bacterial extracellular vesicles (BEVs) allow for the customization of modified BEVs for the therapy of OP. In conclusion, we give a thorough and in-depth summary of the main difficulties and potential future of EVs in the treatment of OP, as well as highlight innovative uses and choices for the treatment of osteoarthritis (OA).

miR-181b regulates vascular endothelial aging by modulating an MAP3K3 signaling pathway

Endothelial cell (EC) aging plays a vital role in the pathogenesis of cardiovascular disease (CVD). MicroRNAs have emerged as crucial regulators of target gene expression by inhibiting mRNA translation and/or promoting mRNA degradation. We identify an aging-related and oxidative stress-responsive microRNA, miR-181b, that inhibits endothelial cell apoptosis and senescence. In gain- or loss-of-function studies, miR-181b regulated the expression of key apoptosis markers (Bcl2, Bax, cleaved-Caspase3) and senescence markers (p16, p21, γH2AX) and the ratio of apoptotic cells (TUNEL-positive) and senescent cells (SA-βgal-positive) in H2 O2 -induced ECs. Mechanistically, miR-181b targets MAP3K3 and modulates a MAP3K3/MKK/MAPK signaling pathway. MAP3K3 knockdown recapitulated the phenotype of miR-181b overexpression and miR-181b was dependent on MAP3K3 for regulating EC apoptosis and senescence. In vivo, miR-181b expression showed a negative correlation with increasing age in the mouse aorta. Endothelial-specific deficiency of miR-181a2b2 increased the target MAP3K3, markers of vascular senescence (p16, p21), and DNA double-strand breaks (γH2AX) in the aorta of aged mice. Collectively, this study unveils an important role of miR-181b in regulating vascular endothelial aging via an MAP3K3-MAPK signaling pathway, providing new potential therapeutic targets for antiaging therapy in CVD.

[Expression of microRNA-296 in rabbit hypertrophic scars and its role to human fibroblasts]

Objective: To investigate the expression of microRNA-296 (miR-296) in rabbit hypertrophic scars and its role in human fibroblasts (HFbs). Methods: The experimental method was used. Twelve healthy adult New Zealand long-eared rabbits regardless gender were randomly divided into normal control group and scar group, with 6 rabbits in each group. The rabbit ear hypertrophic scar model was created in scar group according to the literature, and the rabbits in normal control group did not receive any treatment. On 60 days after setting up the models in scar group, hematoxylin-eosin staining was performed to observe the growth and arrangement of fibroblasts (Fbs) in the ear scars and skin tissue of rabbits in the two groups. The mRNA expressions of miR-296 and transforming growth factor-β1 (TGF-β1) in ear scars and skin tissue of rabbits in the two groups were detected by real-time fluorescent quantitative reverse transcription polymerase chain reaction, and the correlation of mRNA between miR-296 and TGF-β1 was performed with Pearson regression analysis. Two batches of HFbs were used and transfected respectively with corresponding sequences, with the 1st batch being divided into TGF-β1 wild type+miR-296 negative control group and TGF-β1 wild type+miR-296 mimic group and the 2nd batch being divided into TGF-β1 mutant type+miR-296 negative control group and TGF-β1 mutant type+miR-296 mimic group. At 48 h after transfection, luciferase reporter gene detection kit was used to detect the luciferase and renal luciferase expression of TGF-β1 in the cells of each group, with their ratio being used to reflect the gene expression level. Two batches of HFbs were used, and each batch of cells were divided into miR-296 negative control group and miR-296 mimic group, being transfected with the corresponding sequences. At 0 (immediately), 12, 24, 36, and 48 h after transfecting the first batch of cells, the cell proliferation was detected by thiazolyl blue method. At 24 h after transfecting the second batch of cells, the expression of TGF-β1 and collagen type Ⅰ was detected by Western blotting. The number of samples in cell experiments was 3. Data were statistically analyzed with analysis of variance for factorial design, independent sample t test. Results: On 60 days after setting up the models in scar group, the Fbs of rabbit ear scar tissue in scar group proliferated and arranged disorderly, while the growth and arrangement of Fbs in rabbit ear skin tissue in normal control group were normal. The mRNA expression of miR-296 of rabbit scar tissue in scar group (0.65±0.11) was significantly lower than 1.19±0.12 of rabbit ear skin tissue in normal control group (t=5.175, P<0.01). The mRNA expression of TGF-β1 of rabbit ear scar tissue in scar group (1.47±0.06) was significantly higher than 1.10±0.03 of rabbit ear skin tissue in normal control group (t=12.410, P<0.01). Pearson regression analysis showed that there was a negative correlation between the mRNA expression of miR-296 and TGF-β1 in the ear scars and skin tissue of 12 rabbits (F=7.278, P<0.05). At 48 h after transfection, the gene expression of TGF-β1 of cells in TGF-β1 wild type+miR-296 mimic group was significantly lower than that in TGF-β1 wild type+miR-296 negative control group (t=35.190, P<0.01), while the gene expression of TGF-β1 of cells in the two TGF-β1 mutant type groups were close (P>0.05). The HFbs proliferation ability in miR-296 mimic group was significantly lower than that in miR-296 negative control group at 12, 24, 36, and 48 h after transfection(t=3.275, 11.980, 10.460, 17.260, P<0.05 or P<0.01). At 24 h after transfection, the protein expressions of TGF-β1 and type Ⅰ collagen of cells in miR-296 negative control group were significantly higher than those in miR-296 mimic group (t=3.758, 29.390, P<0.05 or P<0.01). Conclusions: The miR-296 expression in rabbit hypertrophic scars is down-regulated; miR-296 can inhibit the proliferation of HFbs and the expression of type Ⅰ collagen by down regulating the expression of TGF-β1.

[Expression and effect of microRNA-627 in human hypertrophic scar]

Objective: To investigate the expression and effect of microRNA-627 (miR-627) in human hypertrophic scar. Methods: The experimental research method was used. From October 2019 to January 2020, hypertrophic scar tissue from 6 patients with hypertrophic scar (2 males and 4 females, aged (34±11) years) and the remaining normal skin tissue from 6 trauma patients (3 males and 3 females, aged (35±13) years) after flap transplantation were collected. The above-mentioned 12 patients were admitted to the General Hospital of Northern Theater Command and met the inclusion criteria. The mRNA expression of miR-627 was detected by real-time fluorescent quantitative reverse transcription polymerase chain reaction. The 3rd to 5th passages of fibroblasts (Fbs) were isolated from hypertrophic scar tissue and cultured for subsequent experiments after identification. Fbs from hypertrophic scar were divided into miR-627 negative control group, miR-627 mimic group, and miR-627 inhibitor group. The corresponding sequences were transfected respectively. At 0 (immediately), 12, 24, 36, and 48 h after transfection, the cell viability was detected by thiazolyl blue method; at 24 h after transfection, the apoptosis was detected by flow cytometry; at 24 h after transfection, the protein expression levels of insulin-like growth factor Ⅰ (IGF-Ⅰ), type Ⅰ collagen, and α smooth muscle actin (α-SMA) were detected by Western blotting. Two batches of Fbs from hypertrophic scar were used, one batch was divided into IGF-Ⅰ wild type+miR-627 negative control group and IGF-Ⅰ wild type+miR-627 mimic group, and the other batch was divided into IGF-Ⅰ mutant+miR-627 negative control group and IGF-Ⅰ mutant+miR-627 mimic group. The corresponding sequences were transfected respectively. At 48 h after transfection, the expressions of luciferase and renal luciferase were detected by luciferase reporter gene detection kit, and the ratio of the two was calculated to reflect the activity of IGF-Ⅰ. Fbs from hypertrophic scar were divided into miR-627 negative control group, miR-627 mimic alone group, and miR-627 mimic+IGF-Ⅰ group, and were transfected with the corresponding sequences respectively. At 24 h after transfection, the protein expression levels of IGF-Ⅰ, type Ⅰ collagen, and α-SMA were detected by Western blotting. The number of samples in cell experiment was 3. Data were statistically analyzed with analysis of variance for factorial design, one-way analysis of variance, independent sample t test, and chi-square test. Results: The expression of miR-627 mRNA in hypertrophic scar tissue was 0.47±0.06, which was significantly lower than 1.12±0.23 in normal skin tissue (t=15.090, P<0.01). At 12, 24, 36, and 48 hours after transfection, the cell viability of miR-627 mimic group was significantly lower than that of miR-627 negative control group (t=9.918, 34.370, 13.580, 61.550, P<0.05 or P<0.01); the cell viability of miR-627 inhibitor group was significantly higher than that of miR-627 negative control group (t=4.722, 8.616, 13.330, 14.000, P<0.05 or P<0.01). At 24 h after transfection, compared with the apoptosis rate (8.42±0.47)% in miR-627 negative control group, (10.89±0.35)% in miR-627 mimic group was significantly higher (t=7.301, P<0.01), and (5.00±0.22)% in miR-627 inhibitor group was significantly lower (t=11.510, P<0.01). At 24 h after transfection, compared with the cell protein expressions of IGF-Ⅰ, type Ⅰ collagen, and α-SMA in miR-627 negative control group, those in miR-627 mimic group were significantly lower (t=25.470, 5.282, 7.415, P<0.01), and those in miR-627 inhibitor group were significantly higher (t=15.930, 8.857, 9.763, P<0.01). At 48 h after transfection, the luciferase/renal luciferase ratio of IGF-Ⅰ of cells in IGF-Ⅰ wild type+miR-627 mimic group was 0.463±0.061, which was significantly lower than 0.999±0.011 in IGF-Ⅰ wild type+miR-627 negative control group (t=16.852, P<0.01); the luciferase/renal luciferase ratio of IGF-Ⅰ of cells in IGF-Ⅰ mutant+miR-627 mimic group was 0.934±0.021, which was similar to 0.930±0.023 in IGF-Ⅰ mutant+miR-627 negative control group (t=1.959, P>0.05). At 24 h after transfection, the protein expressions of IGF-Ⅰ, type Ⅰ collagen, and α-SMA of cells in miR-627 mimic alone group were 1.623±0.070, 1.363±0.042, and 1.617±0.025, which were significantly lower than 2.723±0.045, 2.147±0.067, and 2.533±0.055 in miR-627 negative control group (t=22.831, 7.280, 26.220, P<0.01); the protein expressions of IGF-Ⅰ, type Ⅰ collagen, and α-SMA of cells in mimic+IGF-Ⅰ group were 2.477±0.102, 1.760±0.046, and 2.387±0.049, which were significantly higher than those of miR-627 mimic alone group (t=3.830, 8.286, 3.436, P<0.05 or P<0.01). Conclusions: miR-627 expression in human hypertrophic scars is down-regulated; miR-627 can inhibit the proliferation and promote the apoptosis of Fbs in human hypertrophic scar by targeted inhibition of IGF-Ⅰ expression.

MicroRNA-9-5p inhibits proliferation and induces apoptosis of human hypertrophic scar fibroblasts through targeting peroxisome proliferator-activated receptor β

Hypertrophic scar (HS) is a dermal fibro-proliferative disorder result from abnormal wound healing after skin injury. MicroRNA-9-5p (miR-9-5p) has been reported to be upregulated and closely related to collagen proteins in human dermal fibroblasts. However, the correlation and possible mechanism between miR-9-5p and HS require further investigation. The expressions of miR-9-5p in HS tissues and HS fibroblasts were detected by quantitative real-time PCR (RT-qPCR). The expression level of peroxisome proliferator-activated receptor β (PPARβ) was measured by RT-qPCR assay. The protein levels of PPARβ, α-SMA, Vimentin, COL1A, cyclin D1, bcl-2, and bax were detected by western blot assay. The effect of miR-9-5p and PPARβ on HS fibroblasts proliferation and apoptosis were detected by cell counting kit-8 (CCK-8) and flow cytometry assays. The interaction between miR-9-5p and PPARβ was predicted by TargetScan, and then confirmed by dual-luciferase reporter assay. MiR-9-5p expression was downregulated in HS tissues and HS fibroblasts. MiR-9-5p inhibited the levels of extracellular matrix-associated genes (α-SMA, Vimentin, COL1A) in HS fibroblasts. MiR-9-5p repressed proliferation and induced apoptosis of HS fibroblasts. PPARβ is a target gene of miR-9-5p. The silencing of PPARβ expression hindered proliferation and expedited apoptosis of HS fibroblasts. MiR-9-5p suppressed proliferation and promoted apoptosis of HS fibroblasts by targeting PPARβ. In this paper, we firstly disclosed that miR-9-5p hampered extracellular matrix deposition and proliferation, and induced apoptosis by targeting PPARβ in HS fibroblasts. Our findings provided a new role of miR-9-5p/PPARβ in the occurrence and development of HS fibroblasts, promising a new target for HS.

Summary: Our findings provided a new role of miR-9-5p/PPAR in the occurrence and development of HS fibroblasts, promising a new target for HS.

Circulating miRNA-181b-5p, miRNA-223-3p, miRNA-210-3p, let 7i-5p, miRNA-21-5p and miRNA-29a-3p in patients with localized scleroderma as potential biomarkers

Localized scleroderma (LoSc) is a rare disease manifested by an inflammation and sclerosis of the skin. The latest studies focused on glycoprotein Krebs von den Lungen-6, surfactant protein-D, chemokine ligand 18 and dipeptidylpeptidase 4 as potential biomarkers of skin fibrosis in systemic scleroderma. Our study aimed to identify 6 miRNAs with elevated or decreased levels in 38 LoSc patients (31 females, 7 males) compared to healthy volunteers (HVs) and to correlate the selected miRNAs' serum levels with the severity and the clinical symptoms of LoSc and some laboratory parameters with the selected miRNAs' serum levels. The serum levels of miRNAs, i.e. miRNA-181b-5p, miRNA-223-3p, miRNA-21-5p, let 7i-5p, miRNA-29a-3p and miRNA-210-3p were significantly increased in the LoSc patients compared to the HVs. The level of let-7i increase in the female LoSc patients correlated negatively with BSA (r =  - 0.355, p = 0.049) and mLoSSI (r =  - 0.432, p = 0.015). Moreover, the female patients with inactive LoSc had significantly higher level of let-7i (2.68-fold on average) in comparison to those with active disease (p = 0.045). The exact role of those molecules has not been revealed in LoSc and a long-term longitudinal research is pivotal to confirm their prognostic value.

Advances in scarless foetal wound healing and prospects for scar reduction in adults

Healing after mammalian skin injury involves the interaction between numerous cellular constituents and regulatory factors, which together form three overlapping phases: an inflammatory response, a proliferation phase and a remodelling phase. Any slight variation in these three stages can substantially alter the healing process and resultant production of scars. Of particular significance are the mechanisms responsible for the scar‐free phenomenon observed in the foetus. Uncovering such mechanisms would offer great expectations in the treatment of scars and therefore represents an important area of investigation. In this review, we provide a comprehensive summary of studies on injury‐induced skin regeneration within the foetus. The information contained in these studies provides an opportunity for new insights into the treatment of clinical scars based on the cellular and molecular processes involved.

Osteocyte-derived exosomes induced by mechanical strain promote human periodontal ligament stem cell proliferation and osteogenic differentiation via the miR-181b-5p/PTEN/AKT signaling pathway

BACKGROUND

The oral cavity is a complex environment in which periodontal tissue is constantly stimulated by external microorganisms and mechanical forces. Proper mechanical force helps maintain periodontal tissue homeostasis, and improper inflammatory response can break the balance. Periodontal ligament (PDL) cells play crucial roles in responding to these challenges and maintaining the homeostasis of periodontal tissue. However, the mechanisms underlying PDL cell property changes induced by inflammatory and mechanical force microenvironments are still unclear. Recent studies have shown that exosomes function as a means of cell-cell and cell-matrix communication in biological processes.

METHODS

Human periodontal ligament stem cells (HPDLSCs) were tested by the CCK8 assay, EdU, alizarin red, and ALP staining to evaluate the functions of exosomes induced by a mechanical strain. MicroRNA sequencing was used to find the discrepancy miRNA in exosomes. In addition, real-time PCR, FISH, luciferase reporter assay, and western blotting assay were used to investigate the mechanism of miR-181b-5p regulating proliferation and osteogenic differentiation through the PTEN/AKT pathway.

RESULTS

In this study, the exosomes secreted by MLO-Y4 cells exposed to mechanical strain (Exosome-MS) contributed to HPDLSC proliferation and osteogenic differentiation. High-throughput miRNA sequencing showed that miR181b-5p was upregulated in Exosome-MS compared to the exosomes derived from MLO-Y4 cells lacking mechanical strain. The luciferase reporter assay demonstrated that miR-181b-5p may target phosphatase tension homolog deletion (PTEN). In addition, PTEN was negatively regulated by overexpressing miR-181b-5p. Real-time PCR and western blotting assay verified that miR-181b-5p enhanced the protein kinase B (PKB, also known as AKT) activity and improved downstream factor transcription. Furthermore, miR-181b-5p effectively ameliorated the inhibition of HPDLSC proliferation and promoted HPDLSC induced by inflammation.

CONCLUSIONS

This study concluded that exosomes induced by mechanical strain promote HPDLSC proliferation via the miR-181b-5p/PTEN/AKT signaling pathway and promote HPDLSC osteogenic differentiation by BMP2/Runx2, suggesting a potential mechanism for maintaining periodontal homeostasis.

Inhibition of sphingosine kinase 2 attenuates hypertrophic scar formation via upregulation of Smad7 in human hypertrophic scar fibroblasts

The aims of the present study were to investigate the role of sphingosine kinase 2 (Sphk2) in hypertrophic scar (HS) formation and its underlying mechanisms. The expression levels of Sphk2 and Smad7 in HS tissues and healthy skin tissues of patients undergoing plastic surgery were determined using immunohistochemical staining. Subsequently, the expression levels of Sphk2 and collagen I in human embryonic skin fibroblasts (control) and human HS fibroblasts (HSF) were detected using western blot analysis and immunofluorescence assay, respectively. Following Sphk2 silencing, Smad7 overexpression or both Sphk2 and Smad7 silencing, HSF proliferative ability was assessed using Cell Counting Kit‑8 assay and proliferation‑associated proteins were evaluated using western blot analysis. In addition, the level of apoptosis in HSF was assessed using flow cytometry and expression levels of apoptotic‑associated proteins were determined using western blotting. Furthermore, the expression levels of collagen I and proteins in the TGF‑β1/Smad signaling pathway were detected using western blot analysis. The results indicated that the expression of Sphk2 was significantly increased, while Smad7 expression was decreased in HS tissue. Moreover, the upregulation of Sphk2 and collagen I expression levels was identified in HSF. The present results also indicated that Sphk2 silencing or Smad7 overexpression inhibited proliferation, but promoted apoptosis of HSF, coupled with changes in the expression levels of proliferation‑associated proteins, with an increase in p21 and a decrease in cyclin D1 expression levels, and apoptosis‑associated proteins, with an increase in Bax and cleaved caspase‑3, and a decrease in Bcl‑2, which were reversed following transfection with both Sphk2 and Smad7 using small interfering RNA in HSF. In addition, the expression levels of transforming growth factor‑β1, phosphorylated (p)‑Smad2, p‑Smad3 and collagen I were reduced following Sphk2 silencing or Smad7 overexpression, which were abolished by silencing both Sphk2 and Smad7. Collectively, the present results indicated that inhibition of Sphk2 attenuated HS formation via upregulation of Smad7 expression, thus Sphk2 may serve as a potential therapeutic target for the treatment of HS.

Altered expression of apoptosis-related, circulating cell-free miRNAs in children with familial Mediterranean fever: a cross-sectional study

OBJECTIVES

Familial Mediterranean Fever (FMF) is the most common hereditary autoinflammatory disorder characterized by recurrent fever and serositis episodes. Identification of low penetrant or heterozygous MEFV mutations in clinically diagnosed FMF patients did raise a concern on whether epigenetic or environmental factors play an additional role in FMF pathogenesis. We aimed to investigate the expression profile of apoptosis-related miRNAs in FMF and their influence on clinical manifestations in the present study.

METHOD

191 pediatric FMF patients and 31 healthy children included in the study. Expressions of 33 apoptosis-related, circulating cell-free miRNAs were evaluated by a quantitative polymerase chain reaction, statistically calculated within ΔΔCt values and fold changes were evaluated by Welch T test, in which p < 0.05 were considered to be significant.

RESULTS

Nineteen miRNAs, including let-7a-5p, let-7c, let-7 g-5p, miR-15b-5p, miR-16-5p, miR-17-5p, miR-23a-3p, miR-24-3p, miR-25-3p, miR-26a-5p, miR-26b-5p, miR-27a-3p, miR-29c-3p, miR-30a-5p, miR-30d-5p, miR-30e-5p, miR-106b-5p, miR-146a-5p, and miR-195-5p, were found down-regulated; miR-15a-5p, miR-29b-3p, miR-181a-5p, miR-181b-5p, miR-181c-5p, miR-214-3p, and miR-365a-3p were up-regulated in FMF patients. In detail, these miRNAs were similar among FMF patients in terms of genotype, colchicine response, and having an inflammatory attack during analysis.

CONCLUSION

We found that 26 apoptosis-related circulating miRNAs were deregulated in children with FMF. Thus, we speculate that these miRNAs have a role in FMF pathogenesis via apoptotic mechanisms.

Botulinum toxin type A prevents the phenotypic transformation of fibroblasts induced by TGF‑β1 via the PTEN/PI3K/Akt signaling pathway

Hypertrophic scar (HS) is a common type of dermatosis. Botulinum toxin type A (BTXA) can exert an anti-HS effect; however, the regulatory mechanisms underlying this effect remain unclear. Thus, the aim of this study was to examine the effects of BTXA on phosphatase and tensin homolog deleted on chromosome ten (PTEN) expression and the fibroblast phenotypic transformation induced by transforming growth factor (TGF)-β1, which is an important regulatory factor involved in the process of HS. For this purpose, fibroblasts were treated with various concentrations of BTXA and then treated with 10 ng/ml of TGF-β1 with gradient concentrations of BTXA. The proliferation and apoptosis of fibroblasts were measured by cell counting kit-8 assay (CCK-8) and flow cytometry, respectively. PTEN methylation was analyzed by methylation-specific PCR (MSP) and DNA methyltransferase (DNMT) activity was determined using a corresponding kit. RT-qPCR and western blot analysis were performed to detect the transcription and translation levels. The results revealed that BTXA suppressed the proliferation and increased the apoptosis of fibroblasts treated with TGF-β1 in a dose-dependent manner. BTXA in combination with TGF-β1 suppressed the expression of molecules related to the extracellular matrix (ECM), epithelial-mesenchymal transition (EMT) and apoptosis. BTXA reduced the PTEN methylation level and downregulated the expression levels of methylation-associated genes. BTXA also inhibited the phosphorylation of phosphoinositide 3-kinase (PI3K) and Akt. On the whole, the findings of this study indicate that BTXA may inhibit fibroblast phenotypic transformation by regulating PTEN methylation and the phosphorylation of related pathways. The findings of this study can provide a theoretical basis for HS treatment.