MIR-190B Alleviates Cell Autophagy and Burn-Induced Skeletal Muscle Wasting via Modulating PHLPP1/Akt/FoxO3A Signaling Pathway

Bacterial cellulose as an ideal potential treatment for burn wounds: A comprehensive review

Burn wound regeneration is a complex process, which has many serious challenges such as slow wound healing, secondary infection, and inflammation. Therefore, it is essential to utilise appropriate biomaterials to accelerate and guide the wound healing process. Bacterial cellulose (BC), a natural polymer synthesised by some bacteria, has attracted much attention for wound healing applications due to its unique properties including excellent physicochemical and mechanical properties, simple purification process, three-dimensional (3D) network structure similar to extracellular matrix, high purity, high water holding capacity and significant permeability to gas and liquid. BC's lack of antibacterial activity significantly limits its biomedical and tissue engineering application, but adding antimicrobial agents to it remarkably improves its performance in tissue regeneration applications. Burn wound healing is a complex long-lasting process. Using biomaterials in wound treatment has shown that they can satisfactorily accelerate wound healing. The purpose of this review is to elaborate on the importance of BC-based structures as one of the most widely used modern wound dressings in the treatment of burn wounds. In addition, the combination of various drugs, agents, cells and biomolecules with BC to expand its application in burn injury regeneration is discussed. Finally, the main challenges and future development direction of BC-based structures for burn wound repair are considered. The four most popular search engines PubMed/MEDLINE, Science Direct, Scopus and Google Scholar were used to help us find relevant papers. The most frequently used keywords were bacterial cellulose, BC-based biocomposite, wound healing, burn wound and vascular graft.

miR-181c, a potential mediator for acute kidney injury in a burn rat model with following sepsis

BACKGROUND

The miRNA profile is changed after burn or sepsis and is involved in regulating inflammatory reactions. However, the function and molecular mechanism of miRNAs in regulating burn sepsis-induced acute kidney injury (AKI) are still unclear.

METHODS

In this study, animal and cell sepsis models were established after burned rats were injected with lipopolysaccharide (LPS) or NRK-52E cells treated with LPS, respectively. Cytokine expression, inflammatory cell infiltration, serum creatinine (Scr) and kidney injury molecule-1 (KIM-1) levels were analysed after the indicated treatments.

RESULTS

Burn sepsis increased the expression of inflammatory factors (TNF-α and IL-1β) and chemokines (MIP-1α, MIP-2 and MCP-1). Moreover, burn sepsis promoted macrophage and neutrophil infiltration into the kidney and upregulated the levels of Scr and KIM-1 in the kidney and urine. Ectopic expression of miR-181c significantly reduced LPS-induced TLR4 protein expression, suppressed KIM-1 mRNA levels and subsequently inhibited the activation of inflammatory genes (TNF-α and IL-1β) and chemokine genes (MIP-1α, MIP-2 and MCP-1).

CONCLUSIONS

Our results demonstrated that miR-181c could suppress TLR4 expression, reduce inflammatory factor and chemokine secretion, mitigate inflammatory cell infiltration into the kidney and downregulate KIM-1 expression, which might ultimately attenuate burn sepsis-induced AKI.

Role of autophagy and transcriptome regulation in acute brain injury

Autophagy is an evolutionarily conserved intracellular system that routes distinct cytoplasmic cargo to lysosomes for degradation and recycling. Accumulating evidence highlight the mechanisms of autophagy, such as clearance of proteins, carbohydrates, lipids and damaged organelles. The critical role of autophagy in selective degradation of the transcriptome is still emerging and could shape the total proteome of the cell, and thus can regulate the homeostasis under stressful conditions. Unregulated autophagy that potentiates secondary brain damage is a key pathological features of acute CNS injuries such as stroke and traumatic brain injury. This review discussed the mutual modulation of autophagy and RNA and its significance in mediating the functional consequences of acute CNS injuries.

Human Umbilical Cord-Derived Mesenchymal Stem Cells Alleviate Acute Lung Injury Caused by Severe Burn via Secreting TSG-6 and Inhibiting Inflammatory Response

Objectives

To investigate whether hUC-MSCs attenuated severe burn-induced ALI and the effects were based on TSG-6 secreted from hUC-MSCs.

Method

A rat model was established and evaluated as follows: cytokine expression was measured by ELISA, and both inflammatory cell infiltration and lung injury were assessed by immunohistochemistry assay.

Results

In vitro, TSG-6 levels in serum from the burn group were significantly increased compared with those from the sham group. In vivo, TSG-6 levels of lung tissues and serum in the burn+hUC-MSC group were significantly increased compared with those in the burn group. Both in lung tissues and in serum, increased levels of proinflammatory cytokines (TNF-α, IL-1β, and IL-6) were remarkably decreased, but the anti-inflammatory cytokine IL-10 increased after hUC-MSC administration (p < 0.05). These significant positive effects after hUC-MSC transplantation did not occur in the burn+siTSG-6 group.

Conclusion

The intratracheal implantation of hUC-MSCs has been an effective treatment for severe burn-induced ALI via promoting TSG-6 secretion and inhibiting inflammatory reaction in lung tissue.

The Progress of Nomenclature, Structure, Metabolism, and Bioactivities of Oat Novel Phytochemical: Avenanthramides

Oats are among the most commonly consumed whole grains and are widely grown worldwide, and they contain numerous nutrients, including proteins, lipids, vitamins, minerals, β-glucan, and unique phytochemical polyphenol avenanthramides (Avns). Recent studies have indicated that Avns play essential roles in mediating the health benefits of oats. This review systemically summarized the nomenclature and structures of Avns, effect of germination on promoting Avns production, and in vivo metabolites produced after Avns consumption. The classical functions and novel potential bioactivities of Avns were further elucidated. The classical functions of Avns in cancer prevention, antioxidative response, anti-inflammatory reaction, and maintaining muscle health were expounded, and the internal mechanisms of these functions were analyzed. The potential novel bioactivities of Avns in modulating gut microbiota, alleviating obesity, and preventing chronic diseases, such as atherosclerosis and osteoporosis, were further revealed. This review may provide new prospects and directions for the development and utilization of oat Avns.

mTORC2: The other mTOR in autophagy regulation

The mechanistic target of rapamycin (mTOR) has gathered significant attention as a ubiquitously expressed multimeric kinase with key implications for cell growth, proliferation, and survival. This kinase forms the central core of two distinct complexes, mTORC1 and mTORC2, which share the ability of integrating environmental, nutritional, and hormonal cues but which regulate separate molecular pathways that result in different cellular responses. Particularly, mTORC1 has been described as a major negative regulator of endosomal biogenesis and autophagy, a catabolic process that degrades intracellular components and organelles within the lysosomes and is thought to play a key role in human health and disease. In contrast, the role of mTORC2 in the regulation of autophagy has been considerably less studied despite mounting evidence this complex may regulate autophagy in a different and perhaps complementary manner to that of mTORC1. Genetic ablation of unique subunits is currently being utilized to study the differential effects of the two mTOR complexes. RICTOR is the best‐described subunit specific to mTORC2 and as such has become a useful tool for investigating the specific actions of this complex. The development of complex‐specific inhibitors for mTORC2 is also an area of intense interest. Studies to date have demonstrated that mTORC1/2 complexes each signal to a variety of exclusive downstream molecules with distinct biological roles. Pinpointing the particular effects of these downstream effectors is crucial toward the development of novel therapies aimed at accurately modulating autophagy in the context of human aging and disease.

Integrated Genome-Wide Analysis of MicroRNA Expression Quantitative Trait Loci in Pig Longissimus Dorsi Muscle

Determining mechanisms regulating complex traits in pigs is essential to improve the production efficiency of this globally important protein source. MicroRNAs (miRNAs) are a class of non-coding RNAs known to post-transcriptionally regulate gene expression affecting numerous phenotypes, including those important to the pig industry. To facilitate a more comprehensive understanding of the regulatory mechanisms controlling growth, carcass composition, and meat quality phenotypes in pigs, we integrated miRNA and gene expression data from longissimus dorsi muscle samples with genotypic and phenotypic data from the same animals. We identified 23 miRNA expression Quantitative Trait Loci (miR-eQTL) at the genome-wide level and examined their potential effects on these important production phenotypes through miRNA target prediction, correlation, and colocalization analyses. One miR-eQTL miRNA, miR-874, has target genes that colocalize with phenotypic QTL for 12 production traits across the genome including backfat thickness, dressing percentage, muscle pH at 24 h post-mortem, and cook yield. The results of our study reveal genomic regions underlying variation in miRNA expression and identify miRNAs and genes for future validation of their regulatory effects on traits of economic importance to the global pig industry.

Small in Size, but Large in Action: microRNAs as Potential Modulators of PTEN in Breast and Lung Cancers

MicroRNAs (miRNAs) are well-known regulators of biological mechanisms with a small size of 19–24 nucleotides and a single-stranded structure. miRNA dysregulation occurs in cancer progression. miRNAs can function as tumor-suppressing or tumor-promoting factors in cancer via regulating molecular pathways. Breast and lung cancers are two malignant thoracic tumors in which the abnormal expression of miRNAs plays a significant role in their development. Phosphatase and tensin homolog (PTEN) is a tumor-suppressor factor that is capable of suppressing the growth, viability, and metastasis of cancer cells via downregulating phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling. PTEN downregulation occurs in lung and breast cancers to promote PI3K/Akt expression, leading to uncontrolled proliferation, metastasis, and their resistance to chemotherapy and radiotherapy. miRNAs as upstream mediators of PTEN can dually induce/inhibit PTEN signaling in affecting the malignant behavior of lung and breast cancer cells. Furthermore, long non-coding RNAs and circular RNAs can regulate the miRNA/PTEN axis in lung and breast cancer cells. It seems that anti-tumor compounds such as baicalein, propofol, and curcumin can induce PTEN upregulation by affecting miRNAs in suppressing breast and lung cancer progression. These topics are discussed in the current review with a focus on molecular pathways.

Analysis of the differential expression profile of miRNAs in myocardial tissues of rats with burn injury

Fifteen percent third-degree burn rat model was used to identify miRNAs that are markers of burn injury-induced myocardial damage. Cardiac tissues were evaluated to determine miRNA profile sequencing. Pearson's correlation analysis was used between miRNAs and injury markers. ROC curve analysis was used to estimate miRNA's sensitivity and specificity for the diagnosis of myocardial damage caused by burn injury. The sequencing analysis revealed 23 differentially expressed miRNAs. Pearson's correlation analysis revealed that rno-miR-190b-3p and C5b9, rno-miR-341, rno-miR-344b-3p and TnI, rno-miR-344b-3p and CK-MB were significantly positively correlated, respectively. ROC curve analysis demonstrated that rno-miR-341, rno-miR-344b-3p, and rno-miR-190b-3p exhibited high sensitivity and specificity for the diagnosis of myocardial damage caused by burn injury. In conclusion, our results suggest that rno-miR-341, rno-miR-344b-3p, and rno-miR-190b-3p have the potential to be used as sensitive and specific biomarkers to diagnose myocardial damage caused by burn injury.

Protein Nutritional Support: The Classical and Potential New Mechanisms in the Prevention and Therapy of Sarcopenia

Sarcopenia commonly occurs in the elderly and patients with wasting diseases. The main reason is an imbalance in protein metabolism (protein degradation exceeding protein synthesis). It causes a serious decline in muscle strength and motion ability, even leading to long-term bed rest. Recent studies indicate that nutritional support is beneficial for ameliorating sarcopenia and restoring muscle function. This review will summarize the classical mechanisms of protein nutritional support for alleviating sarcopenia, such as modulating the ubiquitin-proteasome system, oxidative response, and cell autophagy, as well as the potential new mechanisms, including altering miRNA profiles and gut microbiota. In addition, the clinical application and outcome of protein nutritional support in the elderly and patients with wasting diseases are also introduced. Protein nutritional support is expected to provide new approaches for the prevention and adjuvant therapy of sarcopenia.

Erythropoietin Alleviates Burn-induced Muscle Wasting

Background: Burn injury induces long-term skeletal muscle pathology. We hypothesized EPO could attenuate burn-induced muscle fiber atrophy. Methods: Rats were allocated into four groups: a sham burn group, an untreated burn group subjected to third degree hind paw burn, and two burn groups treated with weekly or daily EPO for four weeks. Gastrocnemius muscle was analyzed at four weeks post-burn. Results: EPO attenuated the reduction of mean myofiber cross-sectional area post-burn and the level of the protective effect was no significant difference between two EPO-treated groups (p=0.784). Furthermore, EPO decreased the expression of atrophy-related ubiquitin ligase, atrogin-1, which was up-regulated in response to burn. Compared to untreated burn rats, those receiving weekly or daily EPO groups had less cell apoptosis by TUNEL assay. EPO decreased the expression of cleaved caspase 3 (key factor in the caspase-dependent pathway) and apoptosis-inducing factor (implicated in the caspase-independent pathway) after burn. Furthermore, EPO alleviated connective tissue overproduction following burn via transforming growth factor beta 1-Smad2/3 pathway. Daily EPO group caused significant erythrocytosis compared with untreated burn group but not weekly EPO group. Conclusion: EPO therapy attenuated skeletal muscle apoptosis and fibrosis at four weeks post-burn. Weekly EPO may be a safe and effective option in muscle wasting post-burn.