IL-6/STAT3/miR-34a protects against neonatal lung injury patients

Diagnostic value of miR-34a in Mycoplasma pneumoniae pneumonia in children and its correlation with rehabilitation effect

BACKGROUND

Mycoplasma pneumoniae pneumonia (MPP) is responsible for 20 to 40% of all cases of pneumonia acquired by children and shows an increasing incidence year by year. The aim of this study was to investigate the expression of miR-34a in children with MPP and its diagnostic value, and further explore the relationship between miR-34a and the rehabilitation effect of children with MPP.

METHODS

The expression level of miR-34a was detected by RT-qPCR, and the clinical value of miR-34a was analyzed by ROC analysis. In addition, the levels of IL-6, IL-18 and TNF-α in serum of children with MPP were detected by ELISA kit, and the correlation with miR-34a was analyzed.

RESULTS

Elevated levels of miR-34a were observed in the serum of children with MPP, and significantly higher expression levels were observed in children with severe symptoms and poor rehabilitation. The study suggested that miR-34a has potential as a diagnostic marker for MPP in children, helping to distinguish between mild and severe cases and predicting rehabilitation from MPP in children. In addition, miR-34a expression was positively correlated with IL-6, IL-8, and TNF-α levels.

CONCLUSIONS

miR-34a is closely related to MPP in children and miR-34a may be used as a clinical biomarker for MPP in children.

A novel quantification method of lung fibrosis based on Micro-CT images developed with the optimized pulmonary fibrosis mice model induced by bleomycin

Background and aims

Idiopathic pulmonary fibrosis (IPF) is a fibrosing lung disease with unknown etiology, leading to cough and dyspnoea, which is also one of the most common sequelae affecting the quality of life of COVID-19 survivors. There is no cure for IPF patients. We aim to develop a reliable IPF animal model with quantification of fibrosis based on Micro-Computer Tomography (micro-CT) images for the new drug discovery, because different bleomycin administration routes, doses, and intervals are reported in the literature, and there is no quantitative assessment of pulmonary fibrosis based on micro-CT images in animal studies.

Methods

We compared three dosages (1.25 mg/kg, 2.5 mg/kg, and 5 mg/kg) of intratracheal bleomycin administration and experiment intervals (14 and 21 days) in C57BL/6 mice by investigating survival rates, pulmonary histopathology, micro-CT, peripheral CD4⁺ & CD8⁺ cells, and cytokines. Moreover, a simple and reliable new method was developed for scoring fibrosis in live mice based on Micro-CT images by using Image J software, which transfers the dark sections in pulmonary Micro-CT images to light colors on a black background.

Results

The levels of hydroxyproline, inflammation cytokine, fibrotic pathological changes, and collagen deposition in the lungs of mice were bleomycin dose-dependent and time-dependent as well as the body weight loss. Based on the above results, the mice model at 21 days after being given bleomycin at 1.25 mg/kg has optimal pulmonary fibrosis with a high survival rate and low toxicity. There is a significant decrease in the light area (gray value at 9.86 ± 0.72) in the BLM mice, indicating that a significant decrease in the alveolar air area was observed in BLM injured mice compared to normal groups (###p < 0.001), while the Pirfenidone administration increased the light area (gray value) to 21.71 ± 2.95 which is close to the value observed in the normal mice (gray value at 23.23 ± 1.66), which is consistent with the protein levels of Col1A1, and α-SMA. Notably, the standard deviations for the consecutive six images of each group indicate the precision of this developed quantitation method for the micro-CT image taken at the fifth rib of each mouse.

Conclusion

Provided a quantifying method for Micro-CT images in an optimal and repeatable pulmonary fibrosis mice model for exploring novel therapeutic interventions.

Serum miR-34a-5p and miR-199a-3p as new biomarkers of neonatal sepsis

Background

Neonatal sepsis is a serious condition. Recent clinical studies have indicated that microRNAs (miRNAs) are key players in the pathogenesis of sepsis, which could be used as biomarkers for this condition.

Patients and methods

A total of 90 neonates with sepsis and 90 healthy neonates were enrolled in this study. qRT-PCR was performed to measure the expression levels of serum miR-34a-5p and miR-199a-3p.

Results

miR-34a-5p and miR-199a-3p serum levels were significantly reduced in neonates with sepsis compared with those in healthy neonates (P = 0.006 and P = 0.001, respectively). Significant correlations of miR-34a-5p and miR-199a-3p with each of TLC, RDW, RBS, and C-reactive protein (CRP) as well as SNAPII were observed, indicating their associations with the severity of neonatal sepsis.

Conclusion

miR-34a-5p and miR-199a-3p may be useful as novel biomarkers in neonatal sepsis and may provide a new direction for its treatment.

Circulating microRNAs 34a, 122, and 192 are linked to obesity-associated inflammation and metabolic disease in pediatric patients

BACKGROUND

Obesity-associated chronic low-grade inflammation leads to dysregulation of central lipid and glucose metabolism pathways leading to metabolic disorders. MicroRNAs (miRNAs) are known to control regulators of metabolic homeostasis. We aimed to assess the relationship of circulating miRNAs with inflammatory modulators and metabolic disorders in pediatric obesity.

METHODS

From a pediatric cohort with severe obesity (n = 109), clinically thoroughly characterized including diverse routine blood parameters, oral glucose tolerance test, and liver MRI, a panel of 16 circulating miRNAs was quantified using qRT-PCR. Additionally, markers of inflammation TNFα, IL1 receptor antagonist, procalcitonin, CRP, and IL-6 were measured.

RESULTS

Markers of obesity-associated inflammation, TNFα, IL-1Ra, and procalcitonin, all significantly correlated with concentrations of miRNAs 122 and 192. Concentrations of these miRNAs negatively correlated with serum adiponectin and were among those strongly linked to parameters of dyslipidemia and liver function. Moreover, miRNA122 concentrations correlated with HOMA-IR. Several miRNA levels including miRNAs 34a, 93, 122, and 192 were statistically significantly differing between individuals with prediabetes, impaired glucose tolerance, metabolic syndrome, or nonalcoholic fatty liver disease compared to the respective controls. Additionally, miRNA 192 was significantly elevated in metabolically unhealthy obesity.

CONCLUSIONS

A miRNA pattern associated with obesity-associated inflammation and comorbidities may be used to distinguish metabolically healthy from unhealthy pediatric patients with obesity. Moreover, these changes in epigenetic regulation could potentially be involved in the etiology of obesity-linked metabolic disease in children and adolescents.

MicroRNA-34a deficiency leads to impaired wound closure by augmented inflammation in mice

Background

Proper inflammation resolution is critical for cutaneous wound healing and disordered inflammation resolution results in chronic nonhealing wounds. However, the cellular and molecular mechanisms for resolution of inflammation during skin wound healing are not well understood. MicroRNA-34a is regarded as one tumor suppressor with complexed immune regulatory effects, yet its role during skin wound repair is still unclear.

Methods

Circular full thickness excisional wounds were made on the dorsal skin of C57 mice and miR-34a expression pattern was examined by real time RT-PCR and in situ hybridization. The wound healing rates and histologic morphometric analysis were quantified and compared between wounds treated with antagomir-34a and autologous control antagomir-NC wounds, as well as wounds between miR-34a knockout (KO) and wild type (WT) mice. Immunohistochemistry (IHC) for both MPO and F4/80 were performed to examine the infiltrative neutrophils and macrophages in wounds from miR-34a KO and WT mice. Cytokines including IL-1β, IL-6, TNF-α and IL-10, were detected and analyzed by real time RT-PCR during wound healing. IHC for IL-6 and p-STAT3 were quantified, and WB for p-STAT3 and IL-6R were examined in wounds of miR-34a KO and WT mice.

Results

We found miR-34a was significantly downregulated in the inflammatory phase and back to normal levels in the proliferative phase. Both topical knockdown wounds miR-34a levels by antagomir gel and systematic knockout miR-34a using KO mice resulted in impaired wound healing with delayed re-epithelialization and augmented inflammation. IHC results indicated that there were more residual infiltrative inflammatory cells in the proliferative phase. Moreover, over-activated IL-6/STAT3 signal pathway was identified in the wounds of miR-34a KO mice.

Conclusions

Our findings reveal that miR-34a deficiency augments skin wound inflammation response and leads to impaired wound healing, which suggest that targeted inhibition of miR-34a for tissue repair/regeneration should be with serious consideration.

Sevoflurane reduces inflammatory factor expression, increases viability and inhibits apoptosis of lung cells in acute lung injury by microRNA-34a-3p upregulation and STAT1 downregulation

OBJECTIVE

Evidence has shown that sevoflurane plays a protective role in acute lung injury (ALI) due to its anti-inflammatory and apoptotic-regulating activity. Nevertheless, the mechanism of sevoflurane is still not completely understood. This study intends to discuss the mechanism of sevoflurane on ALI and the possible mechanisms involved.

METHODS

ALI model of rats was established through intravenous injection of endotoxin lipopolysaccharide. microRNA-34a-3p (miR-34a-3p) and signal transducers and activators of transcription 1 (STAT1) expression in lung tissues of ALI rats were detected. The optimal inhaled concentration of sevoflurane was screened, and then the modeled rats were injected with miR-34a-3p inhibitors, overexpressed STAT1 and inhaled 1.0 Minimum Alveolar Concentration (MAC) sevoflurane to determine mean arterial pressure (MAP) of rats, wet weight/dry weight ratio and myeloperoxidase (MPO) activity, oxidative stress- and inflammation-related factors in lung tissues of rats, along with lung cell viability and apoptosis.

RESULTS

MiR-34a-3p was downregulated while STAT1 was upregulated in ALI rats. Sevoflurane of 1.0 MAC was selected as the optimal inhalation concentration. Sevoflurane (1.0 MAC) increased MAP at T3 and reduced MPO activity, alleviated pathological damage, suppressed apoptosis, oxidative stress and inflammation, and induced cell viability in lung tissues of ALI rats. Down-regulated miR-34a-3p or up-regulated STAT reversed the functions of sevoflurane (1.0 MAC) on ALI rats.

CONCLUSION

Collectively, we demonstrate that sevoflurane reduces inflammatory factor expression, increases lung cell viability and inhibits lung cell apoptosis in ALI through upregulation of miR-34a-3p and downregulation of STAT1, which provides new clues for ALI treatment.