Extracellular vesicles from alveolar macrophages harboring phagocytosed methicillin-resistant Staphylococcus aureus induce necroptosis.

Methicillin-resistant Staphylococcus aureus (MRSA) infection, a major cause of hospital- and community-acquired pneumonia, still has a high mortality rate. Extracellular vesicles (EVs), as crucial mediators of intercellular communication, have a significant impact on infectious diseases. However, the role of EVs from alveolar macrophages (AMs) in MRSA pneumonia remains unclear. We report that AMs phagocytose MRSA and release more EVs in mice with MRSA pneumonia. EVs from AMs harboring phagocytosed MRSA exhibit significant proinflammatory effects and induce necroptosis by delivering tumor necrosis factor α (TNF-α) and miR-146a-5p. Mechanically, the upregulated miR-146a-5p in these EVs enhances the phosphorylation of RIPK1, RIPK3, and MLKL by targeting TNF receptor-associated factor 6 (TRAF6), thereby promoting TNF-α-induced necroptosis. The combination of a TNF-α antagonist and an miR-146a-5p antagomir effectively improves the outcomes of mice with MRSA pneumonia. Overall, we reveal the pronecrotic effect of EVs from MRSA-infected AMs and provide a promising target for the prevention and treatment of MRSA pneumonia.

Functional analysis of a panel of molecular markers for diagnosis of systemic lupus erythematosus in rats.

INTRODUCTION: Systemic lupus erythematosus (SLE) is a diverse autoimmune disease that arises from a combination of complex genetic factors and environmental influences. While circRNAs and miRNAs have recently been identified as promising biomarkers for disease diagnosis, their specific expression patterns, and clinical implications in SLE are not yet fully understood. AIM OF THE WORK: The aim of the present study was to determine the role of a panel of noncoding-RNAs specifically circRNAs (circ-TubD1, circ-CDC27, and circ-Med14), along with miRNA (rno-miR-146a-5p) and mRNA (TRAF6), as novel minimally invasive diagnostic biomarkers for experimentally induced SLE. Additionally, the study involved an insilico bioinformatics analysis to explore potential pathways involved in the pathogenesis of SLE, aiming to enhance our understanding of the disease, enable early diagnosis, and facilitate improved treatment strategies. MATERIALS AND METHODS: SLE was induced in rats using single IP injection of incomplete Freund's adjuvant (IFA). The Induction was confirmed by assessing the ANA and anti-ds DNA levels using ELSA technique. qPCR analysis was conducted to assess the expression of selected RNAs in sera collected from a group of 10 rats with induced SLE and a control group of 10 rats. In addition, bioinformatics and functional analysis were used to construct a circRNA-miRNA-mRNA network and to determine the potential function of these differentially expressed circRNAs. RESULTS: SLE rats demonstrated significantly higher expression levels of circ-CDC27, circ-Med14, and rno-miR-146a-5p as well as TRAF6, with lower expression level of circ-TubD1 in sera of SLE rats relative to controls. ROC curve analysis indicated that all the selected non-coding RNAs could serve as potential early diagnostic markers for SLE. In addition, the expression level of circ-TubD1 was negatively correlated with rno-miR-146a-5p, however, rno-miR-146a-5p was positively correlated with TRAF6. Bioinformatic analysis revealed the incorporation of the circRNAs targeted genes in various immune system and neurodegeneration pathways. CONCLUSIONS: Therefore, circRNAs; circ-TubD1, circ-CDC27, and circ-Med14, in addition to the miRNA (rno-miR-146a-5p) and mRNA (TRAF6) may be involved in the development of SLE and may have promising roles for future diagnosis and targeted therapy.

Tofacitinib Regulates Endostatin via Effects on CD147 and Cathepsin S.

Angiogenesis is critical for rheumatoid arthritis (RA) progression. The effects of tofacitinib, a JAK-STAT inhibitor used for RA treatment, on angiogenesis in RA are unclear. We, therefore, evaluated the levels of angiogenic factors in two systems of a human co-culture of fibroblast (HT1080) and monocytic (U937) cell lines treated with tofacitinib and in serum samples from RA patients before and after six months of tofacitinib treatment. Tofacitinib reduced CD147 levels, matrix metalloproteinase-9 (MMP-9) activity, and angiogenic potential but increased endostatin levels and secreted proteasome 20S activity. In vitro, tofacitinib did not change CD147 mRNA but increased miR-146a-5p expression and reduced STAT3 phosphorylation. We recently showed that CD147 regulates the ability of MMP-9 and secreted proteasome 20S to cleave collagen XVIIIA into endostatin. We show here that tofacitinib-enhanced endostatin levels are mediated by CD147, as CD147-siRNA or an anti-CD147 antibody blocked proteasome 20S activity. The correlation between CD147 and different disease severity scores supported this role. Lastly, tofacitinib reduced endostatin' s degradation by inhibiting cathepsin S activity and recombinant cathepsin S reversed this in both systems. Thus, tofacitinib inhibits angiogenesis by reducing pro-angiogenic factors and enhancing the anti-angiogenic factor endostatin in a dual effect mediated partly through CD147 and partly through cathepsin S.

Deletion of miR-146a enhances therapeutic protein restoration in model of dystrophin exon skipping.

Duchenne muscular dystrophy (DMD) is a progressive muscle disease caused by the absence of dystrophin protein. One current DMD therapeutic strategy, exon skipping, produces a truncated dystrophin isoform using phosphorodiamidate morpholino oligomers (PMOs). However, the potential of exon skipping therapeutics has not been fully realized as increases in dystrophin protein have been minimal in clinical trials. Here, we investigate how miR-146a-5p, which is highly elevated in dystrophic muscle, impacts dystrophin protein levels. We find inflammation strongly induces miR-146a in dystrophic, but not wild-type myotubes. Bioinformatics analysis reveals that the dystrophin 3' UTR harbors a miR-146a binding site, and subsequent luciferase assays demonstrate miR-146a binding inhibits dystrophin translation. In dystrophin-null mdx52 mice, co-injection of miR-146a reduces dystrophin restoration by an exon 51 skipping PMO. To directly investigate how miR-146a impacts therapeutic dystrophin rescue, we generated mdx52 with body-wide miR-146a deletion (146aX). Administration of an exon skipping PMO via intramuscular or intravenous injection markedly increases dystrophin protein levels in 146aX vs. mdx52 muscles while skipped dystrophin transcript levels are unchanged supporting a post-transcriptional mechanism of action. Together, these data show that miR-146a expression opposes therapeutic dystrophin restoration, suggesting miR-146a inhibition warrants further research as a potential DMD exon skipping co-therapy.

miR-146a Decreases Inflammation and ROS Production in Aged Dermal Fibroblasts.

Aging is associated with a decline in the functionality of various cell types, including dermal fibroblasts, which play a crucial role in maintaining skin homeostasis and wound healing. Chronic inflammation and increased reactive oxygen species (ROS) production are hallmark features of aging, contributing to impaired wound healing. MicroRNA-146a (miR-146a) has been implicated as a critical regulator of inflammation and oxidative stress in different cell types, yet its role in aged dermal fibroblasts and its potential relevance to wound healing remains poorly understood. We hypothesize that miR-146a is differentially expressed in aged dermal fibroblasts and that overexpression of miR-146a will decrease aging-induced inflammatory responses and ROS production. Primary dermal fibroblasts were isolated from the skin of 17-week-old (young) and 88-week-old (aged) mice. Overexpression of miR-146a was achieved through miR-146a mimic transfection. ROS were detected using a reliable fluorogenic marker, 2,7-dichlorofluorescin diacetate. Real-time PCR was used to quantify relative gene expression. Our investigation revealed a significant reduction in miR-146a expression in aged dermal fibroblasts compared to their younger counterparts. Moreover, aged dermal fibroblasts exhibited heightened levels of inflammatory responses and increased ROS production. Importantly, the overexpression of miR-146a through miR-146a mimic transfection led to a substantial reduction in inflammatory responses through modulation of the NF-kB pathway in aged dermal fibroblasts. Additionally, the overexpression of miR-146a led to a substantial decrease in ROS production, achieved through the downregulation of NOX4 expression in aged dermal fibroblasts. These findings underscore the pivotal role of miR-146a in mitigating both inflammatory responses and ROS production in aged dermal fibroblasts, highlighting its potential as a therapeutic target for addressing age-related skin wound healing.

MicroRNA-146a-5p protects retinal ganglion cells through reducing neuroinflammation in experimental glaucoma.

Neuroinflammation plays important roles in retinal ganglion cell (RGC) degeneration in glaucoma. MicroRNA-146 (miR-146) has been shown to regulate inflammatory response in neurodegenerative diseases. In this study, whether and how miR-146 could affect RGC injury in chronic ocular hypertension (COH) experimental glaucoma were investigated. We showed that in the members of miR-146 family only miR-146a-5p expression was upregulated in COH retinas. The upregulation of miR-146a-5p was observed in the activated microglia and Müller cells both in primary cultured conditions and in COH retinas, but mainly occurred in microglia. Overexpression of miR-146a-5p in COH retinas reduced the levels pro-inflammatory cytokines and upregulated the levels of anti-inflammatory cytokines, which were further confirmed in the activated primary cultured microglia. Transfection of miR-146a-5p mimic increased the percentage of anti-inflammatory phenotype in the activated BV2 microglia, while transfection of miR-146a-5p inhibitor resulted in the opposite effects. Transfection of miR-146a-5p mimic/agomir inhibited the levels of interleukin-1 receptor associated kinase (IRAK1) and TNF receptor associated factor 6 (TRAF6) and phosphorylated NF-κB subunit p65. Dual luciferase reporter gene assay confirmed that miR-146a-5p could directly target IRAK1 and TRAF6. Moreover, downregulation of IRAK1 and TRAF6 by siRNA techniques or blocking NF-κB by SN50 in cultured microglia reversed the miR-146a-5p inhibitor-induced changes of inflammatory cytokines. In COH retinas, overexpression of miR-146a-5p reduced RGC apoptosis, increased RGC survival, and partially rescued the amplitudes of photopic negative response. Our results demonstrate that overexpression of miR-146a-5p attenuates RGC injury in glaucoma by reducing neuroinflammation through downregulating IRAK1/TRAF6/NF-κB signaling pathway in microglia.

Dual Role of microRNA-146a in Experimental Inflammation in Human Pulmonary Epithelial and Immune Cells and Expression in Inflammatory Lung Diseases.

microRNA (miR)-146a emerges as a promising post-transcriptional regulator in various inflammatory diseases with different roles for the two isoforms miR-146a-5p and miR-146a-3p. The present study aimed to examine the dual role of miR-146a-5p and miR-146a 3p in the modulation of inflammation in human pulmonary epithelial and immune cells in vitro as well as their expression in patients with inflammatory lung diseases. Experimental inflammation in human A549, HL60, and THP1 via the NF-kB pathway resulted in the major upregulation of miR-146a-5p and miR-146a-3p expression, which was partly cell-specific. Modulation by transfection with miRNA mimics and inhibitors demonstrated an anti-inflammatory effect of miR-146a-5p and a pro-inflammatory effect of miR-146a-3p, respectively. A mutual interference between miR-146a-5p and miR-146a-3p was observed, with miR-146a-5p exerting a predominant influence. In vivo NGS analyses revealed an upregulation of miR-146a-3p in the blood of patients with cystic fibrosis and bronchiolitis obliterans, while miR-146a-5p levels were downregulated or unchanged compared to controls. The reverse pattern was observed in patients with SARS-CoV-2 infection. In conclusion, miR-146a-5p and miR-146a-3p are two distinct but interconnected miRNA isoforms with opposing functions in inflammation regulation. Understanding their interaction provides important insights into the progression and persistence of inflammatory lung diseases and might provide potential therapeutic options.

Investigating the therapeutic mechanism of Jiedu-Quyu-Ziyin Fang on systemic lupus erythematosus through the ERα-miRNA-TLR7 immune axis.

Jiedu-Quyu-Ziyin Fang (JQZF) is a formula that has been empirically used for the treatment of SLE in clinical practice. JQZF has become an approved hospital prescription in China. Fifteen MRL/lpr mice were randomly divided into three groups: Model, JQZF, and JQZF + GC, with five mice in each group. Five MRL/MPJ mice were used as the Blank group. After 8 weeks of administration, peripheral blood serum was collected to detect anti-dsDNA antibodies and complement C3 levels. Spleen B cells were collected to detect the expression of TLR7 and NF-κBp65 mRNA, and correlation analysis was performed. Transcriptome sequencing analysis was also performed on spleen B cells. Further, key miRNA and key gene mRNA expression were detected by RT-qPCR, and key protein expression levels were detected by Western blot method. Bioinformatics methods predicted that ESR1 is a key target of JQZF action on SLE, hsa-miR-146a-5p is one of the key miRNAs, and KEGG pathway analysis showed that NF-κB signaling pathway is its key signaling pathway. Transcriptome sequencing of MRL/lpr mouse spleen B cells revealed that the differential genes between the JQZF and Model groups were enriched in Toll-like receptor signaling pathway, NF-κB signaling pathway, Estrogen signaling pathway, etc. Animal studies show that JQZF treatment significantly boosts serum C3 and lowers anti-dsDNA antibodies (P < 0.01). On the molecular level, JQZF suppresses TLR7 and NF-κBp65 mRNA in spleen B cells, with TLR7 mRNA positively linked to anti-dsDNA titers and negatively to serum C3. Further cellular work demonstrates that JQZF reverses the increased IRAK1 and TRAF6 expression seen after miR146a inhibition. Additionally, post-ERα inhibition, JQZF continues to upregulate miR146a and more significantly reduces TLR7 mRNA expression (P < 0.01), pointing to ERα's pivotal role in the miR146a-TLR7 axis. These results indicate JQZF alleviates SLE by adjusting the ERα-miR146a-TLR7 loop, showcasing its mechanism and therapeutic potential for SLE.

The involvement of circulating miR-146a and miR-27a in patients with atherosclerotic cardiovascular disease after SARS-CoV-2 infection.

BACKGROUND: Atherosclerotic cardiovascular disease (ASCVD) is a group of clinical diseases based on pathology of atherosclerosis that is the leading cause of mortality worldwide. There is a bidirectional interaction between ASCVD and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Alterations in circulating miRNAs levels are involved in the development of ASCVD in patients infected with SARS-CoV-2, however, the correlation between ASCVD co-infection with SARS-CoV-2 and alterations of cardiac-specific miRNAs is not well understood. HYPOTHESIS: The circulating miR-146a and miR-27a are involved in bidirectional interactions between ASCVD and SARS-CoV-2 infections. METHODS: Circulating miR-146a and miR-27a levels were measured in serum and PBMCs deriving from ASCVD patients and controls after SARS-CoV-2 infection by qRT-PCR analysis. The levels of neutralizing antibodies-resistant SARS-CoV-2 in human serum was determined by competitive magnetic particle chemiluminescence method. Interleukin (IL)-6 levels were detected by automatic biochemical analyzer using electrochemiluminescence. RESULTS: Significant downregulation of circulating miR-146a and upregulation of miR-27a in ASCVD patients after infection with SARS-CoV-2 compared with controls were observed, among which the alterations were more evident in ASCVD patients comorbid with hyperlipidemia and diabetes mellitus. Consistently, correlation analysis revealed that serum miR-146a and miR-27a levels were associated with the levels of lipids and glucose, inflammatory response, and immune function in ASCVD patients. Remarkably, SARS-CoV-2 S protein RBD stimulation of PBMCs derived from both ASCVD and controls significantly downregulated miR-146a, upregulated miR-27a expression levels, and promoted IL-6 release in vitro. CONCLUSIONS: The circulating miR-146a and miR-27a are involved in metabolism, inflammation, and immune levels in patients with ASCVD after SARS-CoV-2 infection, laying the foundation for the development of strategies to prevent the risk of SARS-CoV-2 infection in ASCVD patients.

Low-energy red light-emitting diode irradiation enhances osteogenic differentiation of periodontal ligament stem cells by regulating miR-146a-5p.

AIMS: The study aimed to investigate the role of miR-146a-5p in osteogenesis of hPDLSCs irradiated with low-energy red LEDs. METHODS: After irradiation with 5 J/cm2 red LED, miR-146a-5p expression was detected by real-time quantitative polymerase chain reaction (RT-qPCR), and osteogenic markers expression was determined by RT-qPCR and Western blotting. Alkaline phosphatase (ALP) activity was assessed by ALP staining, and mineralization was assessed by Alizarin Red staining, respectively. Lentiviral vectors were designed to regulate miR-146a-5p expression. Dual-luciferase reporter assay was performed to confirm the targeted relationship between miR-146a-5p and MAPK1. Short hairpin RNA (shRNA) was used to regulate MAPK1 expression. RESULTS: RT-qPCR and western blotting revealed that 5 J/cm2 irradiation elevated the levels of the osteogenic markers osterix (OSX) and bone sialoprotein (BSP) in hPDLSCs. miR-146a-5p is downregulated in hPDLSCs under the low-energy red LED light irradiation. miR-146a-5p underexpression markedly promoted the osteogenic potential of hPDLSCs. miR-146a-5p targeted MAPK1. 5 J/cm2 red LED irradiation rescued the inhibitory effects of upregulated miR-146a-5p on osteogenic differentiation, and the positive influence of red LED irradiation could be reversed by downregulated MAPK1. CONCLUSION: These findings confirm that miR-146a-5p is involved in the effect of LED irradiation on the osteogenic differentiation of hPDLSCs by targeting MAPK1. Red LED irradiation may be a potential clinical adjunct therapy for periodontal regeneration.

Exosomes derived from miR-146a-overexpressing fibroblast-like synoviocytes in cartilage degradation and macrophage M1 polarization: a novel protective agent for osteoarthritis?

Introduction: Pathological changes in the articular cartilage (AC) and synovium are major manifestations of osteoarthritis (OA) and are strongly associated with pain and functional limitations. Exosome-derived microRNAs (miRNAs) are crucial regulatory factors in intercellular communication and can influence the progression of OA by participating in the degradation of chondrocytes and the phenotypic transformation in the polarization of synovial macrophages. However, the specific relationships and pathways of action of exosomal miRNAs in the pathological progression of OA in both cartilage and synovium remain unclear. Methods: This study evaluates the effects of fibroblast-like synoviocyte (FLS)-derived exosomes (FLS-Exos), influenced by miR-146a, on AC degradation and synovial macrophage polarization. We investigated the targeted relationship between miR-146a and TRAF6, both in vivo and in vitro, along with the involvement of the NF-κB signaling pathway. Results: The expression of miR-146a in the synovial exosomes of OA rats was significantly higher than in healthy rats. In vitro, the upregulation of miR-146a reduced chondrocyte apoptosis, whereas its downregulation had the opposite effect. In vivo, exosomes derived from miR-146a-overexpressing FLSs (miR-146a-FLS-Exos) reduced AC injury and chondrocyte apoptosis in OA. Furthermore, synovial proliferation was reduced, and the polarization of synovial macrophages shifted from M1 to M2. Mechanistically, the expression of TRAF6 was inhibited by targeting miR-146a, thereby modulating the Toll-like receptor 4/TRAF6/NF-κB pathway in the innate immune response. Discussion: These findings suggest that miR-146a, mediated through FLS-Exos, may alleviate OA progression by modulating cartilage degradation and macrophage polarization, implicating the NF-κB pathway in the innate immune response. These insights highlight the therapeutic potential of miR-146a as a protective agent in OA, underscoring the importance of exosomal miRNAs in the pathogenesis and potential treatment of the disease.

Dysregulation of miR-146a in human milk of mothers having children with autism.

Autism spectrum disorder (ASD) is a set of neurobehavioral manifestations that impose poor social interaction and stereotyped repetitive patterns. Several mircoRNA (miRNA) dysregulations underpin ASD pathophysiology via impairing the neurogenic niches. For instance, miR-146a and miR-106 differential expressions are linked to deregulation of ASD-related genes and the severity of clinical symptoms, respectively. Breastfeeding provides newborns with many bioactive compounds that support their neurodevelopment including miRNA. Our pilot study evaluated the expression pattern of miR-106a and miR-146a in human milk (HM) of nursing mothers (n = 36) having autistic children compared to age-matched counterparts (n = 36) with neurotypical children as controls. Under sterile conditions, breast milk samples were collected using manual sucking pumps and centrifuged to separate the fat layer. Total RNA was extracted from the lipid fraction, and the expression profiles of both miR-106a and miR-146a were evaluated using quantitative real-time polymerase chain reaction. Among the test group, we reported some factors that were previously linked to HM miRNA perturbations: gestational diabetes, hypertension, and cesarean delivery. HM miR-106a showed comparable expression levels in both mother groups (p = 0.8681), whereas HM miR-146a was significantly downregulated in mothers with autistic children compared to controls (p = 0.0399). Alternatively, HM miR-106 levels were positively associated with two ASD clinical parameters: Childhood Autism Rating Scale (CARS) and communication and language domain of Autism Diagnostic Interview-Revised (ADI-R) (r = 0.6452, p = 0.0003 and r = 0.3958, p = 0.0410, respectively). The receiver operating characteristic (ROC) curves of both maternal HM miR-106a and miR-146a showed poor fitness as predictive biomarkers for ASD. Our findings suggest that the miR-146a differential expression in ASD children may originate at infancy during the lactation period. Thus, maternal pre- and postnatal health care is critical to maintain optimal miRNome in breast milk.

Single-Base Gene Variants in MIR-146A and SCN1A Genes Related to the Epileptogenic Process in Drug-Responsive and Drug-Resistant Temporal Lobe Epilepsy-A Preliminary Study in a Brazilian Cohort Sample.

The drug-resistant temporal lobe epilepsy (TLE) has recently been associated with single nucleotide variants (SNVs) in microRNA(miR)-146a (MIR-146A) (rs2910164) and Sodium Voltage-Gated Channel Alpha Subunit 1 (SCN1A) (rs2298771 and rs3812718) genes. Moreover, no studies have shown an association between these SNVs and susceptibility to drug-resistant and drug-responsive TLE in Brazil. Thus, deoxyribonucleic acid (DNA) samples from 120 patients with TLE (55 drug-responsive and 65 drug-resistant) were evaluated by real-time polymerase chain reaction (RT-PCR). A total of 1171 healthy blood donor individuals from the Online Archive of Brazilian Mutations (ABraOM, from Portuguese Arquivo Brasileiro On-line de Mutações), a repository containing genomic variants of the Brazilian population, were added as a control population for the studied SNVs. MIR-146A and SCN1A relative expression was performed by quantitative RT-PCR (qRT-PCR). The statistical analysis protocol was performed using an alpha error of 0.05. TLE patient samples and ABraOM control samples were in Hardy-Weinberg equilibrium for all studied SNVs. For rs2910164, the frequencies of the homozygous genotype (CC) (15.00% vs. 9.65%) and C allele (37.80% vs. 29.97%) were superior in patients with TLE compared to controls with a higher risk for TLE disease [odds ratio (OR) = 1.89 (95% confidence interval (95%CI) = 1.06-3.37); OR = 1.38 (95%CI = 1.04-1.82), respectively]. Drug-responsive patients also presented higher frequencies of the CC genotype [21.81% vs. 9.65%; OR = 2.58 (95%CI = 1.25-5.30)] and C allele [39.09% vs. 29.97%; OR = 1.50 (95%CI = 1.01-2.22)] compared to controls. For rs2298771, the frequency of the heterozygous genotype (AG) (51.67% vs. 40.40%) was superior in patients with TLE compared to controls with a higher risk for TLE disease [OR = 2.42 (95%CI = 1.08-5.41)]. Drug-resistant patients presented a higher AG frequency [56.92% vs. 40.40%; OR = 3.36 (95%CI = 1.04-17.30)] compared to the control group. For rs3812718, the prevalence of genotypes and alleles were similar in both studied groups. The MIR-146A relative expression level was lower in drug-resistant compared to drug-responsive patients for GC (1.6 vs. 0.1, p-value = 0.049) and CC (1.8 vs. 0.6, p-value = 0.039). Also, the SCN1A relative expression levels in samples from TLE patients were significantly higher in AG [2.09 vs. 1.10, p-value = 0.038] and GG (3.19 vs. 1.10, p-value < 0.001) compared to the AA genotype. In conclusion, the rs2910164-CC and rs2298771-AG genotypes are exerting significant risk influence, respectively, on responsive disease and resistant disease, probably due to an upregulated nuclear factor kappa B (NF-kB) and SCN1A loss of function.

From Bone Remodeling to Wound Healing: An miR-146a-5p-Loaded Nanocarrier Targets Endothelial Cells to Promote Angiogenesis.

Wound healing is a complex challenge that demands urgent attention in the clinical realm. Efficient angiogenesis is a pivotal factor in promoting wound healing. microRNA-146a (miR-146a) inhibitor has angiogenic potential in the periodontal ligament. However, free microRNAs (miRNAs) are poorly delivered into cells due to their limited tissue specificity and low intracellular delivery efficiency. To address this hurdle, we developed a nanocarrier for targeted delivery of the miR-146a inhibitor into endothelial cells. It is composed of a polyethylenimine (PEI)-modified mesoporous silica nanoparticle (MSN) core and a pentapeptide (YIGSR) layer that recognizes endothelial cells. In vitro, we defined that the miR-146a inhibitor and adiponectin (ADP) can modulate angiogenesis and the remodeling of periodontal tissues by activating the ERK and Akt signaling pathways. Then, we confirm the specificity of YIGSR to endothelial cells, and importantly, the nanocarrier effectively delivers the miR-146a inhibitor into endothelial cells, promoting angiogenesis. In a C57 mouse skin wound model, the miR-146a inhibitor is successfully delivered into endothelial cells at the wound site using the nanocarrier, resulting in the formation of new blood vessels with strong CD31 expression. Additionally, no significant differences are found in the expression levels of inflammatory markers interleukin-6 and tumor necrosis factor-α. This outcome not only brings new strategies for angiogenesis but also exhibits broader implications for bone remodeling and wound healing. The breakthrough holds significance for future research and clinical interventions.

MiR-146a alleviates inflammatory bowel disease in mice through systematic regulation of multiple genetic networks.

Introduction: Inflammatory bowel disease (IBD) is a chronic disease involving multiple genes, and the current available targeted drugs for IBD only deliver moderate efficacy. Whether there is a single gene that systematically regulates IBD is not yet known. MiR-146a plays a pivotal role in repression of innate immunity, but its function in the intestinal inflammation is sort of controversy, and the genetic regulatory networks regulated by miR-146a in IBD has not been revealed. Methods: RT-qPCR was employed to detect the expression of miR-146a in IBD patients and in a mouse IBD model induced by dextran sulfate sodium (DSS), and then we generated a miR-146a knock-out mouse line with C57/Bl6N background. The disease activity index was scored in DSS-treated miR-146a deficiency mice and their wild type (WT) littermates. Bulk RNA-sequencing, RT-qPCR and immunostaining were done to illustrate the downstream genetic regulatory networks of miR-146a in flamed colon. Finally, the modified miR-146a mimics were used to treat DSS-induced IBD in miR-146a knock-out and WT IBD mice. Results: We showed that the expression of miR-146a in the colon was elevated in dextran sulfate sodium (DSS)-induced IBD mice and patients with IBD. DSS induced dramatic body weight loss and more significant rectal bleeding, shorter colon length, and colitis in miR-146a knock-out mice than WT mice. The miR-146a mimics alleviated DSS-induced symptoms in both miR-146a-/- and WT mice. Further RNA sequencing illustrated that the deficiency of miR-146a de-repressed majority of DSS-induced IBD-related genes that cover multiple genetic regulatory networks in IBD, and supplementation with miR-146a mimics inhibited the expression of many IBD-related genes. Quantitative RT-PCR or immunostaining confirmed that Ccl3, Saa3, Csf3, Lcn2, Serpine1, Serpine2, MMP3, MMP8, MMP10, IL1A, IL1B, IL6, CXCL2, CXCL3, S100A8, S100A9, TRAF6, P65, p-P65, and IRAK1 were regulated by miR-146a in DSS induced IBD. Among them, MMP3, MMP10, IL6, IL1B, S100A8, S100A9, SERPINE1, CSF3, and IL1A were involved in the active stage of IBD in humans. Discussion: Our date demonstrated that miR-146a acts as a top regulator in C57/BL6N mice to systematically repress multiple genetic regulatory networks involved in immune response of intestine to environment factors, and combinatory treatment with miR-146a-5p and miR-146a-3p mimics attenuates DSS-induced IBD in mice through down-regulating multiple genetic regulatory networks which were increased in colon tissue from IBD patients. Our findings suggests that miR-146a is a top inhibitor of IBD, and that miR-146a-5p and miR-146a-3p mimics might be potential drug for IBD.

Analysis of IL-17A, IL-17F, and miR-146a-5p Prior to Transplantation and Their Role in Kidney Transplant Recipients.

Background/Objectives: The balance between regulatory and Th17 cells plays an important role in maintaining the immune tolerance after kidney transplantation (KTx) which is essential for transplantation success, defined as a long graft survival and an absence of organ rejection. The present study aimed to assess whether the pretransplant characteristics of IL-17A and IL-17F, their receptors, as well as miR-146a-5p, an miRNA associated with IL-17A/F regulation, can predict KTx outcomes. Methods: A group of 108 pre-KTx dialysis patients and 125 healthy controls were investigated for single nucleotide substitutions within genes coding for IL-17A, IL-17F, their IL-17RA/RC receptors, and miR-146a-5p. Genotyping was performed using LightSNiP assays. In addition, IL17-A/F serum concentrations were determined using ELISA while miR-146a-5p expression was analyzed by RT-PCR. Results: The IL-17F (rs763780) G allele prevailed in KTx recipients as compared to healthy individuals (OR = 23.59, p < 0.0001) and was associated with a higher IL-17F serum level (p = 0.0381) prior to transplantation. Higher miR-146a-5p expression before KTx was more frequently detected in recipients with an increased IL-17A serum concentration (p = 0.0177). Moreover, IL-17A (rs2275913) GG homozygosity was found to be associated with an increased incidence of deaths before KTx (OR = 4.17, p = 0.0307). T-cell or acute rejection episodes were more frequently observed among patients with the C allele of miR-146a-5p (rs2910164) (OR = 5.38, p = 0.0531). IL17-RA/-RC genetic variants (p < 0.05) seem to be associated with eGFR values. Conclusions: These results imply that IL-17F (rs763780) polymorphism is associated with the serum level of this cytokine and may be related to the risk of renal disease and transplant rejection together with miR-146a-5p (rs2910164), while the IL-17A (rs2275913) genotype may affect patients' survival before KTx.

MiR-146a reduces fibrosis after glaucoma filtration surgery in rats.

PURPOSE: To explore the impact of microRNA 146a (miR-146a) and the underlying mechanisms in profibrotic changes following glaucoma filtering surgery (GFS) in rats and stimulation by transforming growth factor (TGF)-ß1 in rat Tenon's capsule fibroblasts. METHODS: Cultured rat Tenon's capsule fibroblasts were treated with TGF-ß1 and analyzed with microarrays for mRNA profiling to validate miR-146a as the target. The Tenon's capsule fibroblasts were then respectively treated with lentivirus-mediated transfection of miR-146a mimic or inhibitor following TGF-ß1 stimulation in vitro, while GFS was performed in rat eyes with respective intraoperative administration of miR-146a, mitomycin C (MMC), or 5-fluorouracil (5-FU) in vivo. Profibrotic genes expression levels (fibronectin, collagen Iα, NF-KB, IL-1ß, TNF-α, SMAD4, and α-smooth muscle actin) were determined through qPCR, Western blotting, immunofluorescence staining and/or histochemical analysis in vitro and in vivo. SMAD4 targeting siRNA was further used to treat the fibroblasts in combination with miR-146a intervention to confirm its role in underlying mechanisms. RESULTS: Upregulation of miR-146a reduced the proliferation rate and profibrotic changes of rat Tenon's capsule fibroblasts induced by TGF-ß1 in vitro, and mitigated subconjunctival fibrosis to extend filtering blebs survival after GFS in vivo, where miR-146a decreased expression levels of NF-KB-SMAD4-related genes, such as fibronectin, collagen Iα, NF-KB, IL-1ß, TNF-α, SMAD4, and α-smooth muscle actin(α-SMA). Additionally, SMAD4 is a key target gene in the process of miR-146a inhibiting fibrosis. CONCLUSIONS: MiR-146a effectively reduced TGF-ß1-induced fibrosis in rat Tenon's capsule fibroblasts in vitro and in vivo, potentially through the NF-KB-SMAD4 signaling pathway. MiR-146a shows promise as a novel therapeutic target for preventing fibrosis and improving the success rate of GFS.

miR-146a-5p mediates inflammation-induced ß cell mitochondrial dysfunction and apoptosis.

We previously showed that miR-146a-5p is upregulated in pancreatic islets treated with pro-inflammatory cytokines. Others have reported that miR-146a-5p overexpression is associated with ß cell apoptosis and impaired insulin secretion. However, the molecular mechanisms mediating these effects remain elusive. To investigate the role of miR-146a-5p in ß cell function, we developed stable MIN6 cell lines to either overexpress or inhibit the expression of miR-146a-5p. Monoclonal cell populations were treated with pro-inflammatory cytokines (IL-1ß, IFNγ, and TNFα) to model T1D in vitro. We found that overexpression of miR-146a-5p increased cell death under conditions of inflammatory stress, whereas inhibition of miR-146a-5p reversed these effects. Additionally, inhibition of miR-146a-5p increased mitochondrial DNA copy number, respiration rate, and ATP production. Further, RNA sequencing data showed enrichment of pathways related to insulin secretion, apoptosis, and mitochondrial function when the expression levels of miR-146a-5p were altered. Finally, a temporal increase in miR-146a-5p expression levels and a decrease in mitochondria function markers was observed in islets derived from NOD mice. Collectively, these data suggest that miR-146a-5p may promote ß cell dysfunction and death during inflammatory stress by suppressing mitochondrial function.

Dysregulation of miR-146a is associated with exacerbated inflammation, oxidative and endoplasmic reticulum stress in the progression of diabetic foot ulcer.

Recent evidence has implicated the role of microRNA-146a (miR-146a) in regulating inflammatory responses. In the present study, we investigated the role of miRNA-146a in the progression of diabetic foot ulcer (DFU) in type 2 diabetes mellitus patients (T2DM) and studied its correlation with stress mediators such as Endoplasmic Reticulum (ER) and oxidative stress. Ninety subjects were enrolled and evenly distributed among three groups: Controls (n = 30), T2DM without complications (n = 30) and T2DM with foot ulcers (n = 30). Subsequently, each group was further subdivided based on the University of Texas classification. Peripheral blood was collected from all the study subjects, while tissue biopsies were taken only from DFU patients. Total RNA from both PBMCs and wound tissues were isolated using miRNA isolation kit and qPCR was performed to check the expression of miR-146a, ER stress and oxidative stress markers. Our findings revealed a significant decrease in miR-146a expression among T2DM patients with Grade 2 and Grade 3 DFUs compared with those with Grade 0 and Grade 1 DFUs. Notably, inflammatory genes regulated by miR-146a, including TRAF6, IRAK-1 and ADAM, were all upregulated in T2DM patients with Grade 2 and Grade 3 DFUs. Moreover, reduced miR-146a levels were correlated with increased markers of ER stress and oxidative stress in Grade 2 and Grade 3 DFU patients. Furthermore, our in vitro experiment using mouse 3T3 fibroblasts demonstrated a downregulation of miR-146a following induction of hyperglycaemia, ER stress and oxidative stress in these cells. These findings suggest a potential link between diminished miR-146a expression and heightened oxidative and ER stress in T2DM patients with more severe grades of DFUs. Our results imply that targeting miR-146a may hold therapeutic promise for managing disease progression in DFU patients, as it could help alleviate oxidative and ER stress associated with diabetic complications.