Smad7 down-regulation via ubiquitin degradation mediated by Smurf2 in fibroblasts of hypertrophic scars in burned patients

MALAT1 Knockdown Inhibits the Proliferation, Migration, and Collagen Deposition of Human Hypertrophic Scar Fibroblasts via Targeting miR-29a-3p/Smurf2 Axis

Purpose

Hypertrophic scarring (HS) is commonly described as an abnormal post-traumatic tissue repair characterized by excessive hypercellularity and extracellular matrix (ECM) deposition. Mounting evidence suggests that MALAT1 is maladjusted in many fibrotic diseases, but its contribution to HS progression remains poorly understood. Hence, we sought to elucidate the fundamental role of MALAT1 in HS.

Methods

The expression of MALAT1, miR-29a-3p, and Smurf2 in skin tissues and fibroblasts was assessed by RT-qPCR and Western blotting. Furthermore, lentiviruses, RNAi, or plasmids were utilized to transfect hypertrophic scar fibroblasts (HSFs) for gene overexpression or downregulation. The biological behaviors of HSFs were quantified by the CCK-8 assay, wound healing assay, transwell assay, and flow cytometry. Mechanistically, bioinformatics analysis, dual-luciferase reporter assays, and rescue experiments were performed to verify the relationship between miR-29a-3p and MALAT1 or Smurf2.

Results

Our data indicate that MALAT1, Smurf2 were overexpressed while miR-29a-3p was suppressed in HS tissues and fibroblasts. Downregulation of MALAT1 may lead to decreased proliferation, migration, and invasion of fibroblasts, accompanied by enhanced apoptosis, reduced TGF-β signal transduction, and ECM accumulation in HSFs, by enhancing miR-29a-3p and suppressing Smurf2 expression. Mechanistically, MALAT1 acted as a sponge for miR-29a-3p, while miR-29a-3p directly targeted Smurf2. More importantly, rescue experiments suggested that MALAT1 downregulation induced impact on the proliferation, migration, and invasion of HSFs could be partially overturned through miR-29a-3p knockdown or Smurf2 overexpression.

Conclusion

MALAT1 knockdown inhibits the proliferation, migration, invasion, and collagen deposition of HSFs via targeting the miR-29a-3p/Smurf2 axis, which may reveal a promising therapeutic exploitable vulnerability to HS.

The Pathophysiology and Management of Pathologic Scarring-a Contemporary Review

Significance: Pathologic scarring occurs secondary to imbalances in the cellular mechanisms of wound healing and affects millions of people annually. This review article aims to provide a concise overview of the pathophysiology and management of pathologic scarring for clinicians and scientists alike. Recent Advances: Contemporary research in the field has identified aberrations in transforming growth factor-β/small mothers against decapentaplegic (TGF-β/SMAD) signaling pathways as key drivers of pathologic scar formation; indeed, this pathway is targeted by many treatment modalities and translational investigations currently underway. Although intralesional injection of corticosteroids has been the gold standard in the treatment of pathologic scarring, studies show greater treatment efficacy with the use of combination injections such as triamcinolone/5-fluorouracil and triamcinolone/botulinum toxin. Adjunctive therapies including ablative fractional carbon dioxide/erbium-doped yttrium aluminum garnet and non-ablative pulsed-dye lasers, microneedling, and carboxytherapy have shown encouraging results in small cohort studies. Translational investigations involving the use of nanogels, RNA interference, and small molecules targeting TGF-β/SMAD pathways are also currently underway and hold promise for the future. Critical Issues: The heterogeneous nature of hypertrophic scars and keloids poses significant challenges in formulating standardized treatment and assessment protocols, thereby limiting the conclusions that can be drawn. Future Directions: Rigorous clinical trials into the individual and synergistic effects of these therapies would be ideal before any definitive conclusions or evidence-based treatment recommendations can be made. Owing to the heterogeneity of the pathology and patient population, well-conducted cohort studies may be the next best option.

Smurf2 Regulates Inflammation and Collagen Processing in Cutaneous Wound Healing through Transforming Growth Factor-β/Smad3 Signaling

Wound healing is a highly conserved process that restores the integrity and functionality of injured tissues. Transforming growth factor (TGF)-β is a master regulator of wound healing, whose signaling is attenuated by the E3 ubiquitin ligase Smurf2. Herein, the roles of Smurf2 in cutaneous wound healing were examined using a murine incisional cutaneous model. Loss of Smurf2 increased early inflammation in the wounds and led to narrower wounds with greater breaking strength. Loss of Smurf2 also led to more linearized collagen bundles in normal and wounded skin. Gene expression analyses by real-time quantitative PCR indicated that Smurf2-deficient fibroblasts had increased levels of TGF-β/Smad3 signaling and changes in expression profile of genes related to matrix turnover. The effect of Smurf2 loss on wound healing and collagen bundling was attenuated by the heterozygous loss of Smad3. Together, these results show that Smurf2 affects inflammation and collagen processing in cutaneous wounds by down-regulating TGF-β/Smad3 signaling.

Identification of Novel Biomarkers With Diagnostic Value and Immune Infiltration in Burn Injury

Burn injury is an intractable problem in the field of surgery where screening relevant target genes and exploring pathological mechanisms through bioinformatic methods has become a necessity. Herein, we integrated three burn injury mRNA microarray datasets from the Gene Expression Omnibus database to analyze the hub differentially expressed genes (DEGs) between burn injury patient samples and healthy human samples; we conducted multiple functional enrichment analyses and constructed the protein-protein interaction (PPI) network. Finally, we evaluated the immune infiltration in the burn injury microenvironment. A total of 84 intersection DEGs (32 upregulated and 52 downregulated) were screened in burn injury patients via integrated analyses. Upregulated genes were primarily enriched in regulation of T cell activation, regulation of response to DNA damage stimulus, positive regulation of innate immune response, positive regulation of defense response. We also identified 10 hub genes from the PPI network (CCNB2, MYO10, TTK, POLQ, VASP, TIMP1, CDK16, MMP1, ZYX, and PKMYT1). Next, we found that 22 immune cells were substantially changed during the burn injury by CIBERSORT. In addition, we verified that VASP and POLQ are two novel diagnostic markers in burn processes with high diagnostic efficacy via immunohistochemistry. In summary, we identified several key genes involved in burn injury and provided a favorable basis for elucidating the molecular mechanisms of burn injury through comprehensive bioinformatic analysis.

Identification and functional analysis of a three-miRNA ceRNA network in hypertrophic scars

Background

Hypertrophic scar (HTS) is a fibrotic disorder of skins and may have repercussions on the appearance as well as functions of patients. Recent studies related have shown that competitive endogenous RNA (ceRNA) networks centering around miRNAs may play an influential role in HTS formation. This study aimed to construct and validate a three-miRNA (miR-422a, miR-2116-3p, and miR-3187-3p) ceRNA network, and explore its potential functions.

Methods

Quantitative real‑time PCR (qRT‑PCR) was used to compare expression levels of miRNAs, lncRNAs, and genes between HTS and normal skin. Target lncRNAs and genes of each miRNA were predicted using starBase as well as TargetScan database to construct a distinct ceRNA network; overlapping target lncRNAs and genes of the three miRNAs were utilized to develop a three-miRNA ceRNA network. For every network, protein–protein interaction (PPI) network analysis was performed to identify its hub genes. For each network and its hub genes, Gene Oncology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were conducted to explore their possible functions.

Results

MiR-422a, miR-2116-3p, and miR-3187-3p were all downregulated in HTS tissues and fibroblasts. MiR-422a-based ceRNA network consisted of 101 lncRNAs with 133 genes; miR-2116-3p-centered ceRNA network comprised 85 lncRNAs and 978 genes; miR-3187-3p-derived ceRNA network encompassed 84 lncRNAs as well as 1128 genes. The three-miRNA ceRNA network included 2 lncRNAs with 9 genes, where MAPK1, FOSL2, ABI2, KPNA6, CBL, lncRNA-KCNQ1OT1, and lncRNA-EBLN3P were upregulated. According to GO and KEGG analysis, these networks were consistently related to ubiquitination. Three ubiquitination-related genes (CBL, SMURF2, and USP4) were upregulated and negatively correlated with the expression levels of the three miRNAs in HTS tissues.

Conclusions

This study identified a three-miRNA ceRNA network, which might take part in HTS formation and correlate with ubiquitination.

Inhibin βA is an independent prognostic factor that promotes invasion via Hippo signaling in non‑small cell lung cancer

Inhibin βA (INHBA) serves a prognostic and tumor-promoting role in numerous types of cancer. The present study aimed to determine the clinical significance of INHBA in non-small cell lung cancer (NSCLC) and the mechanisms underlying its potential tumor-promoting effect. INHBA expression was detected in clinical NSCLC samples using immunohistochemistry. In vivo loss- and gain-of-function studies were performed to determine the effects of INHBA on NSCLC invasion. In addition, protein and mRNA expression levels of INHBA, yes-associated protein (YAP), large tumor suppressor 1/2 kinase (LATS1/2), connective tissue growth factor, cysteine rich angiogenic inducer 61 and Merlin were assessed using western blotting and reverse transcription-quantitative PCR, respectively, to investigate the mechanism by which INHBA may affect the invasion of NSCLC. The present study revealed that INHBA was significantly upregulated in 238 clinical NSCLC samples compared with its expression levels in paired adjacent non-cancerous tissues, and in metastatic nodules compared with in primary tumors. Notably, high INHBA expression was statistically associated with clinicopathological features, including poor differentiation and advanced tumor stage. INHBA positivity was statistically related to decreased 5-year overall survival, for which INHBA was an independent prognostic factor. Furthermore, INHBA promoted NSCLC invasion in vitro. In NSCLC, INHBA expression was associated with the nuclear levels of YAP and INHBA overexpression enhanced the invasive abilities of NSCLC cells via inhibiting the Hippo pathway. Mechanistically, INHBA inhibited l LATS1/2 phosphorylation and induced YAP nuclear translocation by downregulating the protein expression levels of Merlin. In conclusion, INHBA may negatively regulate the Hippo pathway to act as a tumor promotor, and could represent a marker of prognosis in NSCLC.

Diversity and Composition of Gut Bacterial Community in Giant Panda with Anorexia

The giant panda (GP) is the most precious animal in China. Gastrointestinal tract disease, especially associated with dysbiosis of gut microbiota, is the leading cause of death in GPs. Here, we performed 16S rRNA high-throughput sequencing to investigate the gut microbiota of GPs having symptoms of anorexia. Results showed that gut microbiota of GP with anorexia had lower richness (Chao1 index) than the healthy GP. However, no significant differences in alpha diversity were observed. There is a significance in the microbial structure between anorexia and healthy GPs. The abundance of phylum Firmicutes (99.23% ± 7.1%), unidentified genus Clostridiales (24.75% ± 2.5%), was significantly higher in the subadult anorexia group (P < 0.01), and that of the unidentified genus Clostridiales (4.53% ± 1.2%) was also significantly higher in the adult anorexia group (P < 0.01). Weissella and Streptococcus were found to be decreased in both anorexia groups. The decreased abundance of Weissella (0.02% ± 0.0%, 0.08% ± 0.0%) and Streptococcus (73.89% ± 4.3%, 91.15% ± 7.6%) and increase in Clostridium may cause symptoms of anorexia in giant pandas. The correlation analysis indicated that there is a symbiotic relationship among Streptococcus, Leuconostoc, Weissella, and Bacillus which are classified as probiotics (r > 0.6, P < 0.05). Importantly, a negative correlation has been found between Streptococcus and unidentified_Clostridium in two groups (r > 0.6, P < 0.05). Our results suggested that Streptococcus might be used as probiotics to control the growth of Clostridium causing the anorexia.