miR9 inhibits 6-mer HA-induced cytokine production and apoptosis in human chondrocytes by reducing NF-kB activation

Unlocking the Potential of miRNAs in Sepsis Diagnosis and Prognosis: From Pathophysiology to Precision Medicine

The clinical syndrome appears as a dysregulated host response to infection that results in life-threatening organ dysfunction known as Sepsis. Sepsis is a serious public health concern where for every five deaths in ICU there is one patient who dies with sepsis worldwide. Sepsis is featured as unbalanced inflammation and immunosuppression which is sustained and profound, increasing patient susceptibility to secondary infections and mortality. microRNAs (miRNAs) play a central role in the control of many biological processes, and the deregulation of their expression has been linked to the development of oncological, cardiovascular, neurodegenerative, and metabolic diseases. In this review, we discuss the role of miRNAs in sepsis pathophysiology. Overall, miRNAs are seen as promising biomarkers, and it has been proposed to develop miRNA-based diagnosis and therapies for sepsis. Yet, the picture is not so straightforward because of miRNAs' versatile and dynamic features. More research is needed to clarify the expression and role of miRNAs in sepsis and promote the use of miRNAs for sepsis management. This study provides an extensive, current, and thorough analysis of the involvement of miRNAs in sepsis. Its purpose is to encourage future research in this area, as tiny miRNAs have the potential to be used for rapid diagnosis, prognosis, and treatment of sepsis.

miR-21 attenuated inflammation targeting MyD88 in human chondrocytes stimulated with Hyaluronan oligosaccharides

Inflammation is the body's response to injuries, which depends on numerous regulatory factors. Among them, miRNAs have gained much attention for their role in regulating inflammatory gene expression at multiple levels. In particular, miR-21 is up-regulated during the inflammatory response and reported to be involved in the resolution of inflammation by down-regulating pro-inflammatory mediators, including MyD88. Herein, we evaluated the regulatory effects of miR-21 on the TLR-4/MyD88 pathway in an in vitro model of 6-mer HA oligosaccharides-induced inflammation in human chondrocytes. The exposition of chondrocytes to 6-mer HA induced the activation of the TLR4/MyD88 pathway, which culminates in NF-kB activation. Changes in miR-21, TLR-4, MyD88, NLRP3 inflammasome, IL-29, Caspase1, MMP-9, iNOS, and COX-2 mRNA expression of 6-mer HA-stimulated chondrocytes were examined by qRT-PCR. Protein amounts of TLR-4, MyD88, NLRP3 inflammasome, p-ERK1/2, p-AKT, IL-29, caspase1, MMP-9, p-NK-kB p65 subunit, and IKB-a have been evaluated by ELISA kits. NO and PGE2 levels have been assayed by colorimetric and ELISA kits, respectively. HA oligosaccharides induced a significant increase in the expression of the above parameters, including NF-kB activity. The use of a miR-21 mimic attenuated MyD88 expression levels and the downstream effectors. On the contrary, treatment with a miR-21 inhibitor induced opposite effects. Interestingly, the use of a MyD88 siRNA confirmed MyD88 as the target of miR-21 action. Our results suggest that miR-21 expression could increase in an attempt to reduce the inflammatory response, targeting MyD88.

The Effects of Seleno-Methionine in Cadmium-Challenged Human Primary Chondrocytes

Cadmium (Cd) is a potentially toxic element able to interfere with cellular functions and lead to disease or even death. Cd accumulation has been demonstrated in cartilage, where it can induce damage in joints. The aim of this study was to evaluate the effect of CdCl2 on primary cultures of human chondrocytes and the possible protective effect of seleno-methionine (Se-Met). Human primary articular chondrocytes were cultured and treated as follows: control groups, cells challenged with 7.5 μM and 10 μM CdCl2 alone, and cells pretreated with 10 and 20 μM Se-Met and then challenged with 7.5 μM and 10 μM CdCl2. Twenty-four hours after incubation, cell viability, histological evaluation with hematoxylin-eosin stain, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay were performed. Furthermore, reverse transcription-PCR was carried out to evaluate mRNA levels of BAX, BAK1, CASP-3, and CASP-9. After CdCl2 challenge at both doses, a reduced cell viability and an overexpression of BAX, BAK1, CASP-3, and CASP-9 genes, as well as a high number of TUNEL-positive cells, were demonstrated, all parameters becoming higher as the dose of CdCl2 was increased. The pretreatment with Se-Met lowered the expression of all considered genes, improved cell viability and morphological changes, and reduced the number of TUNEL-positive cells. It was concluded that Se-Met plays a protective role against CdCl2-induced structural and functional changes in chondrocytes in vitro, as it improved cell viability and showed a positive role in the context of the apoptotic pathways. It is therefore suggested that a translational, multifaceted approach, with plant-based diets, bioactive functional foods, nutraceuticals, micronutrients, and drugs, is possibly advisable in situations of environmental pollution caused by potentially toxic elements.

MicroRNA 9 Is a Regulator of Endothelial to Mesenchymal Transition in Diabetic Retinopathy

Purpose

Diabetic retinopathy (DR) is a significant cause of blindness. Most research around DR focus on late-stage developments rather than early changes such as early endothelial dysfunction. Endothelial-to-mesenchymal transition (EndMT), an epigenetically regulated process whereby endothelial cells lose endothelial characteristics and adopt mesenchymal-like phenotypes, contributes to early endothelial changes in DR. The epigenetic regulator microRNA 9 (miR-9) is suppressed in the eyes during DR. MiR-9 plays a role in various diseases and regulates EndMT-related processes in other organs. We investigated the role miR-9 plays in glucose-induced EndMT in DR.

Methods

We examined the effects of glucose on miR-9 and EndMT using human retinal endothelial cells (HRECs). We then used HRECs and an endothelial-specific miR-9 transgenic mouse line to investigate the effect of miR-9 on glucose-induced EndMT. Finally, we used HRECs to probe the mechanisms through which miR-9 may regulate EndMT.

Results

We found that miR-9 inhibition was both necessary and sufficient for glucose-induced EndMT. Overexpression of miR-9 prevented glucose-induced EndMT, whereas suppressing miR-9 caused glucose-like EndMT changes. We also found that preventing EndMT with miR-9 overexpression improved retinal vascular leakage in DR. Finally, we showed that miR-9 regulates EndMT at an early stage by regulating EndMT-inducing signals such as proinflammatory and TGF-β pathways.

Conclusions

We have shown that miR-9 is an important regulator of EndMT in DR, potentially making it a good target for RNA-based therapy in early DR.

The protective activity of natural flavonoids against osteoarthritis by targeting NF-κB signaling pathway

Osteoarthritis (OA) is a typical joint disease associated with chronic inflammation. The nuclear factor-kappaB (NF-κB) pathway plays an important role in inflammatory activity and inhibiting NF-κB-mediated inflammation can be a potential strategy for treating OA. Flavonoids are a class of naturally occurring polyphenols with anti-inflammatory properties. Structurally, natural flavonoids can be divided into several sub-groups, including flavonols, flavones, flavanols/catechins, flavanones, anthocyanins, and isoflavones. Increasing evidence demonstrates that natural flavonoids exhibit protective activity against the pathological changes of OA by inhibiting the NF-κB signaling pathway. Potentially, natural flavonoids may suppress NF-κB signaling-mediated inflammatory responses, ECM degradation, and chondrocyte apoptosis. The different biological actions of natural flavonoids against the NF-κB signaling pathway in OA chondrocytes might be associated with the differentially substituted groups on the structures. In this review, the efficacy and action mechanism of natural flavonoids against the development of OA are discussed by targeting the NF-κB signaling pathway. Potentially, flavonoids could become useful inhibitors of the NF-κB signaling pathway for the therapeutic management of OA.

Proteoglycans in Toll-like receptor responses and innate immunity

The extracellular matrix (ECM) is an active and dynamic feature of tissues that not only provides gross structure but also plays key roles in cellular responses. The ever-changing microenvironment responds dynamically to cellular and external signals, and in turn influences cell fate, tissue development, and response to environmental injury or microbial invasion. It is therefore paramount to understand how the ECM components interact with each other, the environment and cells, and how they mediate their effects. Among the ECM components that have recently garnered increased attention, proteoglycans (PGs) deserve special note. Recent evidence strongly suggests that they play a crucial role both in health maintenance and disease development. In particular, proteoglycans dictate whether homeostasis or cell death will result from a given injury, by triggering and modulating activation of the innate immune system, via a conserved array of receptors that recognize exogenous (infectious) or endogenous (tissue damage) molecular patterns. Innate immune activation by proteoglycans has important implications for the understanding of cell-matrix interactions in health and disease. In this review, we will summarize the current state of knowledge of innate immune signaling by proteoglycans, discuss the implications, and explore future directions to define progress in this area of extracellular matrix biology.