miR-146a Protects against Staphylococcus aureus-Induced Osteomyelitis by Regulating Inflammation and Osteogenesis

Intracellular Staphylococcus aureus in osteoblasts and osteocytes and its impact on bone homeostasis during osteomyelitis

Osteomyelitis is a severe infection of bone tissue that can lead to bone loss and even osteonecrosis. This condition is mostly caused by Gram-positive bacteria, with Staphylococcus aureus being the most common etiological agent. Among the pathophysiological mechanisms involved in osteomyelitis, the ability of S. aureus to be internalized by osteoblasts or osteocytes and to survive within these cells, is particularly noteworthy. Infected osteoblasts and osteocytes not only serve as reservoirs in chronic cases of osteomyelitis but also play an active role in the osteoimmunology process, notably by producing mediators that promote the bone resorption activity of osteoclasts, thereby disrupting bone homeostasis. The present review explores both historical and recent literature on the internalization of S. aureus by osteoblasts and osteocytes, its intracellular behavior following internalization, and its mechanisms for inducing cell death. Additionally, it examines how S. aureus affects bone formation activity and promotes the production of inflammatory and pro-osteoclastic mediators. This review aims to highlight the limitations of current findings and outline key questions for future investigations.

Correlation of multiple peripheral blood parameters with metastasis and invasion of papillary thyroid cancer: a retrospective cohort study

OBJECTIVE

Papillary thyroid cancer (PTC) progression is characterized by lymph node metastasis and thyroid capsular invasion. This study aimed to identify high-risk PTC populations for these events based on peripheral blood test parameters and to determine the associated factors.

METHODS

This retrospective study analyzed data from 4557 PTC patients. Principal component analysis (PCA) and cluster analysis were performed on 45 peripheral blood test results. High- and low-risk clusters were defined based on metastasis and invasion prevalence. Univariate and multivariate analyses identified parameters significantly differentiating the clusters, examining their association with tumor progression.

RESULTS

Preoperative blood tests stratified patients into two distinct clusters. Cluster 0 demonstrated significantly higher rates of metastasis and invasion than Cluster 1, defining it as the high-risk group. PCA identified four principal components significantly differentiating the clusters. Analysis of these components revealed key peripheral blood parameters. Multivariable logistic regression identified six parameters associated with increased risk of Cluster 0: alanine aminotransferase, free triiodothyronine, thrombin time, hemoglobin, hematocrit, and leukocyte count. Conversely, aspartate aminotransferase and neutrophil count were associated with decreased risk.

CONCLUSION

These findings suggest that peripheral blood parameters may provide insights into the progression of thyroid tumors and highlight potential avenues for exploring the underlying mechanisms of PTC. However, given the retrospective nature of this study and the potential for selection bias, further prospective studies are necessary to validate these results and confirm their predictive value in clinical practice.

Explore on the Mechanism of miRNA-146a/TAB1 in the Regulation of Cellular Apoptosis and Inflammation in Ulcerative Colitis Based on NF-κB Pathway

OBJECTIVE

Ulcerative colitis (UC) is a chronic non-specific inflammatory disease of the rectum and colon with unknown etiology. A growing number of evidence suggest that the pathogenesis of UC is related to excessive apoptosis and production of inflammatory cytokines. However, the functions and molecular mechanisms associated with UC remain unclear.

MATERIALS AND METHODS

The in vivo and in vitro models of UC were established in this study. MiRNA or gene expression was measured by qRT-PCR assay. ELISA, CCK-8, TUNEL, and flow cytometry assays were applied for analyzing cellular functions. The interactions between miR-146a and TAB1 were verified by luciferase reporter and miRNA pull-down assays.

RESULTS

MiR-146a was obviously increased in UC patients, DSS-induced colitis mice, and TNF-α-induced YAMC cells, when compared to the corresponding controls. MiR- 146a knockdown inhibited the inflammatory response and apoptosis in DSS-induced colitis mice and TNF-α-induced YAMC cells. Mechanistically, we found that TAB1 was the target of miR-146a and miR-146a knockdown suppressed the activation of NF-κB pathway in UC. More importantly, TAB1 could overturn the inhibitory effect of antagomiR-146a on cell apoptosis and inflammation in UC.

CONCLUSION

MiR-146a knockdown inhibited cell apoptosis and inflammation via targeting TAB1 and suppressing NF-κB pathway, suggesting that miR-146a may be a new therapeutic target for UC treatment.

Application of extracellular vesicles in diabetic osteoporosis

As the population ages, the occurrence of osteoporosis is becoming more common. Diabetes mellitus is one of the factors in the development of osteoporosis. Compared with the general population, the incidence of osteoporosis is significantly higher in diabetic patients. Diabetic osteoporosis (DOP) is a metabolic bone disease characterized by abnormal bone tissue structure due to hyperglycemia and insulin resistance, reduced bone strength and increased risk of fractures. This is a complex mechanism that occurs at the cellular level due to factors such as blood vessels, inflammation, and hyperglycemia and insulin resistance. Although the application of some drugs in clinical practice can reduce the occurrence of DOP, the incidence of fractures caused by DOP is still very high. Extracellular vesicles (EVs) are a new communication mode between cells, which can transfer miRNAs and proteins from mother cells to target cells through membrane fusion, thereby regulating the function of target cells. In recent years, the role of EVs in the pathogenesis of DOP has been widely demonstrated. In this article, we first describe the changes in the bone microenvironment of osteoporosis. Second, we describe the pathogenesis of DOP. Finally, we summarize the research progress and challenges of EVs in DOP.

Unlocking the Therapeutic Potential of Adipose-Derived Stem Cell Secretome in Oral and Maxillofacial Medicine: A Composition-Based Perspective

The adipose-derived stem cell (ADSC) secretome is widely studied for its immunomodulatory and regenerative properties, yet its potential in maxillofacial medicine remains largely underexplored. This review takes a composition-driven approach, beginning with a list of chemokines, cytokines, receptors, and inflammatory and growth factors quantified in the ADSC secretome to infer its potential applications in this medical field. First, a review of the literature confirmed the presence of 107 bioactive factors in the secretome of ADSCs or other types of mesenchymal stem cells. This list was then analyzed using the Search Tool for Retrieval of Interacting Genes/Proteins (STRING) software, revealing 844 enriched biological processes. From these, key processes were categorized into three major clinical application areas: immunoregulation (73 factors), bone regeneration (13 factors), and wound healing and soft tissue regeneration (27 factors), with several factors relevant to more than one area. The most relevant molecules were discussed in the context of existing literature to explore their therapeutic potential based on available evidence. Among these, TGFB1, IL10, and CSF2 have been shown to modulate immune and inflammatory responses, while OPG, IL6, HGF, and TIMP1 contribute to bone regeneration and tissue repair. Although the ADSC secretome holds great promise in oral and maxillofacial medicine, further research is needed to optimize its application and validate its clinical efficacy.

A Multifunctional Nanocomplex as miRNA/Antibiotic Co-Delivery System Based on Tetrahedral Framework DNA: Application to Infected Wound Healing

Infected wounds are a complex disease involving bacterial infections and dysregulated inflammation. However, current research has mostly focused on bacterial inhibition rather than on inflammation. Thus, combined therapeutic strategies with anti-bacterial and anti-inflammation efficacies are urgently needed. Antibiotics are the main treatment strategy for infections. However, the excessive use of antibiotics throughout the body can cause serious side effects. In addition, miRNA-based therapeutics are superior for the treatment of wounds, but their rapid degradation and poor cellular uptake limit their clinical application. Tetrahedral framework DNA (tFNA) is an ideal drug delivery system owing to its excellent stability and remarkable transport ability. Herein, a novel multi-functional miRNA and antibiotic co-delivery system based on tFNA is presented for the first time, called B/L. B/L has heightened resistance to serum and excellent codelivery ability. After transdermal administration, B/L can specifically target TNF receptor-associated factor 6(TRAF6) and IL-1receptor-associated kinase 1(IRAK1), thereby regulating nuclear factor kappa-B (NF-𝜿B) and thus effectively reducing inflammation and promoting the healing of infected wounds. This novel multi-functional co-delivery system provides a versatile, simple, biocompatible, and powerful platform for the personalized and combined treatment of multiple diseases.

Canine mesenchymal stem cell-derived exosomes attenuate renal ischemia-reperfusion injury through miR-146a-regulated macrophage polarization

Introduction

The most common factor leading to renal failure or death is renal IR (ischemia-reperfusion). Studies have shown that mesenchymal stem cells (MSCs) and their exosomes have potential therapeutic effects for IR injury by inhibiting M1 macrophage polarization and inflammation. In this study, the protective effect and anti-inflammatory mechanism of adipose-derived mesenchymal stem cell-derived exosomes (ADMSC-Exos) after renal IR were investigated.

Method

Initially, ADMSC-Exos were intravenously injected into IR experimental beagles, and the subsequent assessment focused on inflammatory damage and macrophage phenotype. Furthermore, an in vitro inflammatory model was established by inducing DH82 cells with LPS. The impact on inflammation and macrophage phenotype was then evaluated using ADMSC and regulatory miR-146a.

Results

Following the administration of ADMSC-Exos in IR canines, a shift from M1 to M2 macrophage polarization was observed. Similarly, in vitro experiments demonstrated that ADMSC-Exos enhanced the transformation of LPS-induced macrophages from M1 to M2 type. Notably, the promotion of macrophage polarization by ADMSC-Exos was found to be attenuated upon the inhibition of miR-146a in ADMSC-Exos.

Conclusion

These findings suggest that miR-146a plays a significant role in facilitating the transition of LPS-induced macrophages from M1 to M2 phenotype. As a result, the modulation of macrophage polarization by ADMSC-Exos is achieved via the encapsulation and conveyance of miR-146a, leading to diminished infiltration of inflammatory cells in renal tissue and mitigation of the inflammatory reaction following canine renal IR.

Naringin exerts antibacterial and anti-inflammatory effects on mice with Staphylococcus aureus-induced osteomyelitis

Osteomyelitis is an invasive bone infection that can lead to severe pain and even disability, posing a challenge for orthopedic surgery. Naringin can reduce bone-related inflammatory conditions. This study aimed to elucidate the function and mechanism of naringin in a Staphylococcus aureus-induced mouse model of osteomyelitis. Femurs of S. aureus-infected mice were collected after naringin administration and subjected to microcomputed tomography to analyze cortical bone destruction and bone loss. Bacterial growth in femurs was also assessed. Proinflammatory cytokine levels in mouse femurs were measured using enzyme-linked immunosorbent assays. Pathological changes and bone resorption were analyzed using hematoxylin and eosin staining and tartrate-resistant acid phosphatase staining, respectively. Quantitative reverse transcription polymerase chain reaction and western blot analysis were used to quantify the messenger RNA and protein expression of osteogenic differentiation-associated genes in the femurs. The viability of human bone marrow-derived stem cells (hBMSCs) was determined using cell counting kit-8. Alizarin Red S staining and alkaline phosphatase staining were performed to assess the formation of mineralization nodules and bone formation in vitro. Notch signaling-related protein levels in femur tissues and hBMSCs were assessed using western blot analysis. Experimental results revealed that naringin alleviated S. aureus-induced cortical bone destruction and bone loss in mice by increasing the bone volume/total volume ratio. Naringin suppressed S. aureus-induced bacterial growth and inflammation in femurs. Moreover, it alleviated histopathological changes, inhibited bone resorption, and increased the expression of osteogenic markers in osteomyelitic mice. It increased the viability of hBMSCs and promoted their differentiation and bone mineralization in vitro. Furthermore, naringin activated Notch signaling by upregulating the protein levels of Notch1, Jagged1, and Hes1 in the femurs of model mice and S. aureus-stimulated hBMSCs. In conclusion, naringin reduces bacterial growth, inflammation, and bone resorption while upregulating the expression of osteogenic markers in S. aureus-infected mice and hBMSCs by activating Notch signaling.

Osteo-immunomodulatory effects of macrophage-derived extracellular vesicles treated with biphasic calcium phosphate ceramics on bone regeneration

Literature on osteoimmunology has demonstrated that macrophages have a great influence on biomaterial-induced bone formation. However, there are almost no reports clarifying the osteo-immunomodulatory capacity of macrophage-derived extracellular vesicles (EVs). This study comprehensively investigated the effects of EVs derived from macrophages treated with biphasic calcium phosphate (BCP) ceramics (BEVs) on vital events associated with BCP-induced bone formation such as immune response, angiogenesis, and osteogenesis. It was found that compared with EVs derived from macrophages alone (control, CEVs), BEVs preferentially promoted macrophage polarization towards a wound-healing M2 phenotype, enhanced migration, angiogenic differentiation, and tube formation of human umbilical vein endothelial cells, and induced osteogenic differentiation of mesenchymal stem cells. Analysis of 15 differentially expressed microRNAs (DEMs) related to immune, angiogenesis, and osteogenesis suggested that BEVs exhibited good immunomodulatory, pro-angiogenic, and pro-osteogenic abilities, which might be attributed to their specific miRNA cargos. These findings not only deepen our understanding of biomaterial-mediated osteoinduction, but also suggest that EVs derived from biomaterial-treated macrophages hold great promise as therapeutic agents with desired immunomodulatory capacity for bone regeneration.

Neutrophil microRNAs

Neutrophils are considered 'first-line defence' cells as they can be rapidly recruited to the site of the immune response. As key components of non-specific immune mechanisms, neutrophils use phagocytosis, degranulation, and formation of neutrophil extracellular traps (NETs) to fight pathogens. Recently, immunoregulatory abilities of neutrophils associated with the secretion of several mediators, including cytokines and extracellular vesicles (EVs) containing, among other components, microRNAs (miRNAs), have also been reported. EVs are small structures released by cells into the extracellular space and are present in all body fluids. Microvesicles show the composition and status of the releasing cell, its physiological state, and pathological changes. Currently, EVs have gained immense scientific interest as they act as transporters of epigenetic information in intercellular communication. This review summarises findings from recent scientific reports that have evaluated the utility of miRNA molecules as biomarkers for effective diagnostics or even as start-points for new therapeutic strategies in neutrophil-mediated immune reactions. In addition, this review describes the current state of knowledge on miRNA molecules, which are endogenous regulators of gene expression besides being involved in the regulation of the immune response.

Osteomyelitis and non-coding RNAS: A new dimension in disease understanding

Osteomyelitis, a debilitating bone infection, presents considerable clinical challenges due to its intricate etiology and limited treatment options. Despite strides in surgical and chemotherapeutic interventions, the treatment landscape for osteomyelitis remains unsatisfactory. Recent attention has focused on the role of non-coding RNAs (ncRNAs) in the pathogenesis and progression of osteomyelitis. This review consolidates current knowledge on the involvement of distinct classes of ncRNAs, including microRNAs, long ncRNAs, and circular RNAs, in the context of osteomyelitis. Emerging evidence from various studies underscores the potential of ncRNAs in orchestrating gene expression and influencing the differentiation of osteoblasts and osteoclasts, pivotal processes in bone formation. The review initiates by elucidating the regulatory functions of ncRNAs in fundamental cellular processes such as inflammation, immune response, and bone remodeling, pivotal in osteomyelitis pathology. It delves into the intricate network of interactions between ncRNAs and their target genes, illuminating how dysregulation contributes to the establishment and persistence of osteomyelitic infections. Understanding their regulatory roles may pave the way for targeted diagnostic tools and innovative therapeutic interventions, promising a paradigm shift in the clinical approach to this challenging condition. Additionally, we delve into the promising therapeutic applications of these molecules, envisioning novel diagnostic and treatment approaches to enhance the management of this challenging bone infection.

Dysregulation of immunity by cigarette smoking promotes inflammation and cancer: A review

Smoking is a serious global health issue. Cigarette smoking contains over 7000 different chemicals. The main harmful components include nicotine, acrolein, aromatic hydrocarbons and heavy metals, which play the key role for cigarette-induced inflammation and carcinogenesis. Growing evidences show that cigarette smoking and its components exert a remarkable impact on regulation of immunity and dysregulated immunity promotes inflammation and cancer. Therefore, this comprehensive and up-to-date review covers four interrelated topics, including cigarette smoking, inflammation, cancer and immune system. The known harmful chemicals from cigarette smoking were summarized. Importantly, we discussed in depth the impact of cigarette smoking on the formation of inflammatory or tumor microenvironment, primarily by affecting immune effector cells, such as macrophages, neutrophils, and T lymphocytes. Furthermore, the main molecular mechanisms by which cigarette smoking induces inflammation and cancer, including changes in epigenetics, DNA damage and others were further summarized. This article will contribute to a better understanding of the impact of cigarette smoking on inducing inflammation and cancer.

Latest Advances in the Application of Humanized Mouse Model for Staphylococcus aureus

Staphylococcus aureus (S. aureus) is an important pathogen for humans and can cause a wide range of diseases, from mild skin infections, severe osteomyelitis to fatal pneumonia, sepsis, and septicemia. The mouse models have greatly facilitated the development of S. aureus studies. However, due to the substantial differences in immune system between mice and humans, the conventional mouse studies are not predictive of success in humans, in which case humanized mice may overcome this limitation to some extent. Humanized mice can be used to study the human-specific virulence factors produced by S. aureus and the mechanisms by which S. aureus interacts with humans. This review outlined the latest advances in humanized mouse models used in S. aureus studies.

Molecular events in the jaw vascular unit: A traditional review of the mechanisms involved in inflammatory jaw bone diseases

Inflammatory jaw bone diseases are common in stomatology, including periodontitis, peri-implantitis, medication-related osteonecrosis of the jaw, radiation osteomyelitis of the jaw, age-related osteoporosis, and other specific infections. These diseases may lead to tooth loss and maxillofacial deformities, severely affecting patients' quality of life. Over the years, the reconstruction of jaw bone deficiency caused by inflammatory diseases has emerged as a medical and socioeconomic challenge. Therefore, exploring the pathogenesis of inflammatory diseases associated with jaw bones is crucial for improving prognosis and developing new targeted therapies. Accumulating evidence indicates that the integrated bone formation and dysfunction arise from complex interactions among a network of multiple cell types, including osteoblast-associated cells, immune cells, blood vessels, and lymphatic vessels. However, the role of these different cells in the inflammatory process and the 'rules' with which they interact are still not fully understood. Although many investigations have focused on specific pathological processes and molecular events in inflammatory jaw diseases, few articles offer a perspective of integration. Here, we review the changes and mechanisms of various cell types in inflammatory jaw diseases, with the hope of providing insights to drive future research in this field.

Craniofacial therapy: advanced local therapies from nano-engineered titanium implants to treat craniofacial conditions

Nano-engineering-based tissue regeneration and local therapeutic delivery strategies show significant potential to reduce the health and economic burden associated with craniofacial defects, including traumas and tumours. Critical to the success of such nano-engineered non-resorbable craniofacial implants include load-bearing functioning and survival in complex local trauma conditions. Further, race to invade between multiple cells and pathogens is an important criterion that dictates the fate of the implant. In this pioneering review, we compare the therapeutic efficacy of nano-engineered titanium-based craniofacial implants towards maximised local therapy addressing bone formation/resorption, soft-tissue integration, bacterial infection and cancers/tumours. We present the various strategies to engineer titanium-based craniofacial implants in the macro-, micro- and nano-scales, using topographical, chemical, electrochemical, biological and therapeutic modifications. A particular focus is electrochemically anodised titanium implants with controlled nanotopographies that enable tailored and enhanced bioactivity and local therapeutic release. Next, we review the clinical translation challenges associated with such implants. This review will inform the readers of the latest developments and challenges related to therapeutic nano-engineered craniofacial implants.

Recent advancements of miRNAs in the treatment of bone diseases and their delivery potential

Advances in understanding miRNAs as endogenous posttranscriptional regulatory units have projected them as novel therapeutics for several untreatable diseases. miRNAs are endogenous non-coding small single-stranded RNA molecules (20-24 nucleotides) with specific gene regulatory functions like repression of mRNA translation by degrading mRNAs. Emerging evidence suggests the role of miRNAs in various stages of bone growth and development. Undoubtedly, due to their critical role in bone remodeling, miRNAs might be projected as a novel approach to treating bone-related diseases. However, the instability associated with miRNAs in their complex environment, such as degradation by nucleases, is a concern. Thus, recent attention is being paid to maintaining the miRNAs' safety and efficacy in the cells. Various efficient delivery systems and chemical modifications of miRNAs are being developed to make them a potential therapeutic option for bone diseases. Here, we have tried to recapitulate the recent advances in the role of miRNAs in bone disease, along with the potential delivery systems for their efficient delivery to the cells.

microRNA-146a mediates distraction osteogenesis via bone mesenchymal stem cell inflammatory response

Distraction osteogenesis (DO) is a widely used surgical technique to repair bone defects, partly owing to its high efficiency in inducing osteogenesis; however, the process of osteogenesis is complex, and the precise mechanism is still unclear. Among the factors identified for an effective DO procedure, well-controlled inflammation is essential. We aimed to explore how microRNA(miR)-146a, a negative regulator of inflammation, influences osteogenesis in DO. First, we established canine right mandibular DO and bone fracture models to evaluate the expression level of miR-146a in response to these procedures. Second, bone marrow mesenchymal stem cells (BMSCs) were isolated from healthy puppies and cultured with lipopolysaccharide (LPS) to observe how inflammation affects osteogenesis. Finally, the osteogenesis activity of BMSCs transfected with lentiviral vector either overexpressing (miR-146a-up) or inhibited for miR-146a expression was evaluated. miR-146a-up-transfected BMSCs were injected locally into the distraction gaps of the DO model canines. On days 42 and 56 post-surgery, the bone volume/tissue volume and bone mineral density values were evaluated via using micro-computed tomography, and newly formed tissues were harvested and evaluated via histological staining. The expression of miR-146a in both the DO canine model and LPS-stimulated BMSCs increased. Overexpression of miR-146a enhanced cell proliferation, migration, and osteogenic differentiation. Additionally, the newly formed callus was improved in canine mandibles injected with miR-146a-up-transfected BMSCs. In summary, miR-146a regulates mandibular DO by improving osteogenesis, and can serve as a potential target to shorten the therapy period of DO.