miR-29a is a potential protective factor for fibrogenesis in gluteal muscle contracture

MicroRNA-29a Mitigates Laminectomy-Induced Spinal Epidural Fibrosis and Gait Dysregulation by Repressing TGF-β1 and IL-6

Spinal epidural fibrosis is one of the typical features attributable to failed back surgery syndrome, with excessive scar development in the dura and nerve roots. The microRNA-29 family (miR-29s) has been found to act as a fibrogenesis-inhibitory factor that reduces fibrotic matrix overproduction in various tissues. However, the mechanistic basis of miRNA-29a underlying the overabundant fibrotic matrix synthesis in spinal epidural scars post-laminectomy remained elusive. This study revealed that miR-29a attenuated lumbar laminectomy-induced fibrogenic activity, and epidural fibrotic matrix formation was significantly lessened in the transgenic mice (miR-29aTg) as compared with wild-type mice (WT). Moreover, miR-29aTg limits laminectomy-induced damage and has also been demonstrated to detect walking patterns, footprint distribution, and moving activity. Immunohistochemistry staining of epidural tissue showed that miR-29aTg was a remarkably weak signal of IL-6, TGF-β1, and DNA methyltransferase marker, Dnmt3b, compared to the wild-type mice. Taken together, these results have further strengthened the evidence that miR-29a epigenetic regulation reduces fibrotic matrix formation and spinal epidural fibrotic activity in surgery scars to preserve the integrity of the spinal cord core. This study elucidates and highlights the molecular mechanisms that reduce the incidence of spinal epidural fibrosis, eliminating the risk of gait abnormalities and pain associated with laminectomy.

Immunomodulatory Properties of Human Breast Milk: MicroRNA Contents and Potential Epigenetic Effects

Infants who are exclusively breastfed in the first six months of age receive adequate nutrients, achieving optimal immune protection and growth. In addition to the known nutritional components of human breast milk (HBM), i.e., water, carbohydrates, fats and proteins, it is also a rich source of microRNAs, which impact epigenetic mechanisms. This comprehensive work presents an up-to-date overview of the immunomodulatory constituents of HBM, highlighting its content of circulating microRNAs. The epigenetic effects of HBM are discussed, especially those regulated by miRNAs. HBM contains more than 1400 microRNAs. The majority of these microRNAs originate from the lactating gland and are based on the remodeling of cells in the gland during breastfeeding. These miRNAs can affect epigenetic patterns by several mechanisms, including DNA methylation, histone modifications and RNA regulation, which could ultimately result in alterations in gene expressions. Therefore, the unique microRNA profile of HBM, including exosomal microRNAs, is implicated in the regulation of the genes responsible for a variety of immunological and physiological functions, such as FTO, INS, IGF1, NRF2, GLUT1 and FOXP3 genes. Hence, studying the HBM miRNA composition is important for improving the nutritional approaches for pregnancy and infant's early life and preventing diseases that could occur in the future. Interestingly, the composition of miRNAs in HBM is affected by multiple factors, including diet, environmental and genetic factors.

miR-491-5p Inhibits Emilin 1 to Promote Fibroblasts Proliferation and Fibrosis in Gluteal Muscle Contracture via TGF-β1/Smad2 Pathway

Gluteal muscle contracture (GMC) is a chronic fibrotic disease of gluteal muscles due to multiple etiologies. Emilin 1 plays a determinant role in fibers formation, but its role in the progression of GMC remains unclear. The present study was aimed to search for the predictive role and regulatory mechanism of Emilin 1 on GMC. Here, Protein and mRNA expression of Emilin 1 were decreased in GMC tissues compared to normal muscle tissues. Using the analysis of target prediction, Emilin 1 was observed to be a potential downstream sponge of miR-491-5p. In comparison to Emilin 1, miR-491-5p showed an aberrant elevation in GMC tissues, which was further proven to have a negative correlation with Emilin 1. The direct binding of miR-491-5p to Emilin 1 mRNA was confirmed by luciferase reporter gene assay, and miR-491-5p mimics inhibited, while miR-491-5p inhibitor promoted the protein expression and secretion of Emilin 1 in contraction bands (CB) fibroblasts. Additionally, miR-491-5p mimics promoted the expression of cyclin-dependent kinase 2 and cyclin D1 and the proliferation of CB fibroblasts, which could be reversed by Emilin 1 overexpression. Mechanistically, miR-491-5p mimics possibly activated transforming growth factor β1 (TGF-β1)/Smad3 signal cascade via binding to 3’-untranslated region of Emilin 1 mRNA, thereby promoting the progression of fibrosis of CB fibroblasts. Collectively, miR-491-5p inhibited Emilin 1 expression, and subsequently promoted CB fibroblasts proliferation and fibrosis via activating TGF-β1/Smad3 signal axis. MiR-491-5p might be a potentially effective biomarker for predicting GMC, providing a novel therapeutic strategy for GMC.

Tranexamic acid combined with compression dressing reduces blood loss in gluteal muscle contracture surgery

Background

Blood loss and incision-related complications caused by the surgical procedure to release gluteal muscle contracture (GMC) put negative effects on the surgical outcomes. Current procedures to prevent blood loss and complications are not satisfactory. The current study aimed to determine whether tranexamic acid (TXA) in combination with pressure dressing reduce the amount of blood loss, the rate of incision-related complications, and the rate of readmission for patients undergoing surgeries to release GMC.

Methods

49 GMC patients were finally included in the study and were randomly divided into two groups: study group and control group. Patients in both groups received minimally invasive surgery to release GMC except that in the study group, patients were administered a dosage of 20 mg/kg of intravenous TXA preoperatively, and 2 subsequent dosages of TXA at 10 mg/kg at two time points: 3 and 6 h after the first dose. Gauze soaked with TXA was used to pack the wound for 10 min before the incision closure. Then the wound was pressure-wrapped with a hip-spica bandage for 24 h after the surgery in the study group.

Results

The level of UBL in the study group was significantly lower compared to that in the control group. Similar results were also found for UMHD and UMAD. The incision-related postoperative complications were greatly decreased in the study group compared to those of the control group as well. So was the 30-day readmission rate. All patients in both groups reached “excellent” or “good” level with respect to the postoperative function evaluation.

Conclusions

Intravenous and topical application of TXA combined with 24 h pressure hip-spica bandage reduces perioperative blood loss, rate of incision-related complications, and the rate of readmission for GMC patients undergoing minimally invasive surgical releasing procedure.

Trial Registration Chinese Clinical and Trial Registry ChiCTR2000039216, registration date 2020/10/22, retrospectively registered

The correlation of the miR-29a/MMP9 axis with Helicobacter pylori infection in gastric cancer

OBJECTIVE

This study was designed to investigate the association between the miR-29a/MMP9 axis expression levels and Helicobacter pylori (HP) infection in gastric cancer patients.

METHODS

A total of 100 gastric cancer patients referred to our hospital from June 2017 to June 2019 were recruited as the study cohort. Among them, 50 HP-positive patients were included in the experimental group and 50 HP-negative patients were included in the control group. The changes in the patients' conditions were compared, the miR-29a/MMP9 axis expression levels were recorded, and the correlation between the miR-29a/MMP9 axis and the HP infections was analyzed. All the discharged patients were followed up for one year to analyze the correlation between the HP infections and the serum miR-29a and MMP9 expression levels with the disease progression.

RESULTS

The experimental group had higher miR-29a expression levels and higher MMP9 chromogenic scores than the control group (P<0.05). A negative correlation was found between the miR-29 expression level and the MMP9 expression level (r=-5.369, P<0.05). One year after discharge, there were 27 patients with severe disease in the experimental group and 6 in the control group, with a significant difference between the two groups. Moreover, the expression levels of the miR-29a/MMP9 axis were significantly higher in the discharged patients than in the patients with severe disease (P<0.05). A receiver operating characteristic (ROC) curve was used to analyze the predictive value of miR-29/MMP9 in the diagnosis of gastric cancer, and the area under the curve was found to be 0.97.

CONCLUSION

The miR-29a/MMP9 axis levels were increased in the HP positive patients but not in the HP negative patients. HP infection is considered to be closely related to gastric cancer cell spread, disease relapse, and high miR-29a/MMP9 axis expression levels.

Leonurine Attenuates Myocardial Fibrosis Through Upregulation of miR-29a-3p in Mice Post-myocardial Infarction

ABSTRACT

Myocardial fibrosis (MF) is a pathological process that accelerates cardiac remodeling in myocardial infarction (MI), and miR-29 has become one of the foci of research into MF. As an alkaloid extracted from Herba leonuri, leonurine (LE) has been found to be an effective natural active ingredient for inhibiting fibrosis in many preclinical experiments. However, whether LE protects against MF after MI through modifying miR-29 remains unclear. The present study aimed to investigate the therapeutic effects of LE on MF, and to elucidate the underlying mechanisms involved. A mouse model of MI was established, followed by administration of LE for 4 weeks. We found that LE effectively improved cardiac function, and attenuated fibrosis and cardiac remodeling in mice post-MI. In vitro, LE simultaneously inhibited proliferation and migration of neonatal mouse cardiac fibroblasts (CFs) exposed to angiotensin II (Ang II), and the activation of collagen synthesis and myofibroblast generation was markedly suppressed by LE. Notably, we found that all mature miR-29 family members were downregulated in the myocardial tissues of mice post-MI, whereas LE significantly upregulated miR-29a-3p expression, and such upregulation was also detected in LE-treated CFs under Ang II stimulation. Knockdown of miR-29a-3p by a specific miRNA inhibitor upregulated the protein levels of TGF-β, collagen III, and collagen I in CFs, and completely reversed the antifibrotic effects of LE on CFs. Our study suggests that LE exerts cardioprotective effects against MF, possibly through the upregulation of miR-29a-3p.