MicroRNA-27a Inhibits Cell Migration and Invasion of Fibroblast-Like Synoviocytes by Targeting Follistatin-Like Protein 1 in Rheumatoid Arthritis

Plasma MicroRNAs in Established Rheumatoid Arthritis Relate to Adiposity and Altered Plasma and Skeletal Muscle Cytokine and Metabolic Profiles

Background: MicroRNAs have been implicated in the pathogenesis of rheumatoid arthritis (RA), obesity, and altered metabolism. Although RA is associated with both obesity and altered metabolism, expression of RA-related microRNA in the setting of these cardiometabolic comorbidities is unclear. Our objective was to determine relationships between six RA-related microRNAs and RA disease activity, inflammation, body composition, and metabolic function. Methods: Expression of plasma miR-21, miR-23b, miR-27a, miR-143, miR-146a, and miR-223 was measured in 48 persons with seropositive and/or erosive RA (mean DAS-28-ESR 3.0, SD 1.4) and 23 age-, sex-, and BMI-matched healthy controls. Disease activity in RA was assessed by DAS-28-ESR. Plasma cytokine concentrations were determined by ELISA. Body composition was assessed using CT scan to determine central and muscle adipose and thigh muscle tissue size and tissue density. Plasma and skeletal muscle acylcarnitine, amino acid, and organic acid metabolites were measured via mass-spectroscopy. Plasma lipoproteins were measured via nuclear magnetic resonance (NMR) spectroscopy. Spearman correlations were used to assess relationships for microRNA with inflammation and cardiometabolic measures. RA and control associations were compared using Fisher transformations. Results: Among RA subjects, plasma miR-143 was associated with plasma IL-6 and IL-8. No other RA microRNA was positively associated with disease activity or inflammatory markers. In RA, microRNA expression was associated with adiposity, both visceral adiposity (miR-146a, miR-21, miR-23b, and miR-27a) and thigh intra-muscular adiposity (miR-146a and miR-223). RA miR-146a was associated with greater concentrations of cardiometabolic risk markers (plasma short-chain dicarboxyl/hydroxyl acylcarnitines, triglycerides, large VLDL particles, and small HDL particles) and lower concentrations of muscle energy substrates (long-chain acylcarnitines and pyruvate). Despite RA and controls having similar microRNA levels, RA, and controls differed in magnitude and direction for several associations with cytokines and plasma and skeletal muscle metabolic intermediates. Conclusion: Most microRNAs thought to be associated with RA disease activity and inflammation were more reflective of RA adiposity and impaired metabolism. These associations show that microRNAs in RA may serve as an epigenetic link between RA inflammation and cardiometabolic comorbidities.

The function of ncRNAs in rheumatic diseases

Rheumatic diseases are a group of chronic heterogeneous autoimmune disorders characterized by abnormal regulation of the innate and adaptive immune systems. Despite extensive efforts, the full spectrum of molecular factors that contribute to the pathogenesis of rheumatic diseases remains unclear. ncRNAs can govern gene expression at the transcriptional and post-transcriptional levels in multiple diseases. Recent studies have demonstrated an important role for ncRNAs, such as miRNAs and lncRNAs, in the development of immune cells and rheumatic diseases. Here, we focus on the epigenetic regulatory roles of ncRNAs in the pathogenesis of rheumatic diseases and as biomarkers of disease state.

MiRNA-506 inhibits rheumatoid arthritis fibroblast-like synoviocytes proliferation and induces apoptosis by targetting TLR4

Fibroblast-like synoviocytes (FLSs) play a crucial role in rheumatoid arthritis (RA) pathogenesis. While miRNA (miR)-506 has been implicated in the progression of multiple diseases, its role in RA remains to be explored. The present study evaluated the function of miR-506 in the regulation of RA-FLSs. FLSs were prepared from RA and healthy synovial tissues. The expression of miR-506 was measured by quantitative real time PCR (qRT-PCR). The effects of miR-506 on RA-FLSs proliferation and apoptosis were detected by cell counting Kit-8 and flow cytometry assays, respectively. The determination of TNF-α, IL-6, and IL-1β concentrations in RA-FLSs supernatant were done by ELISA. The levels of miR-506 were detected to be significantly lower in the synovial tissues and FLSs of RA than in the synovial tissues and FLSs of healthy controls. The miR-506 up-regulation in RA-FLSs significantly inhibited the proliferation and promoted cell cycle arrest at the G₀/G₁ phase. The overexpression of miR-506 induced apoptosis, along with an increase in activities of caspase-3 and -8. A target gene Toll-like receptor 4 (TLR4) under the direct regulation of miR-506 was identified through the luciferase assay, qRT-PCR and western blot analysis. Forced overexpression of TLR4 in the rescue experiments showed that TLR4 effectively reversed the effect on proliferation and apoptosis in miR-506-overexpressing RA-FLSs. Thus, miR-506 may be a potential target for RA prevention and therapy of RA.

Inhibition of MicroRNA-9-5p Protects Against Cardiac Remodeling Following Myocardial Infarction in Mice

Follistatin-like 1 (Fstl1) protects cardiomyocytes from a broad spectrum of pathologic injuries including myocardial infarction (MI). It is worthy of note that although cardiac Fstl1 is elevated in post-MI microenvironment, its cardioprotective role is still restricted to a limited extent considering the frequency and severity of adverse cardiac remodeling following MI. We therefore propose that intrinsic Fstl1-suppressing microRNA (miRNA) may exist in the heart and its neutralization may further facilitate post-MI recovery. Here, miR-9-5p is predicted as one of the potential Fstl1-targeting miRNAs whose expression is decreased in ischemic myocardium and reversely correlated with Fstl1. Luciferase activity assay further validated Fstl1 as a direct target of miR-9-5p. In addition, forced expression of miR-9-5p in H9c2 cells is concurrent with diminished expression of Fstl1 and vice versa. Importantly, transfection of miR-9-5p mimics in hypoxic H9c2 cells exacerbates cardiac cell death, lactate dehydrogenase release, reactive oxygen species accumulation, and malonyldialdehyde concentration. More importantly, in vivo silencing of miR-9-5p by a specific antagomir in a murine acute MI model effectively preserves post-MI heart function with attenuated fibrosis and inflammatory response. Further studies demonstrated that antagomir treatment stabilizes Fstl1 expression as well as blocks cardiac cell death and reactive oxygen species generation in both ischemia-challenged hearts and hypoxia-treated cardiomyoblasts. Finally, cytoprotection against hypoxic challenge by miR-9-5p inhibitor is partially reversed by knockdown of Fstl1, indicating a novel role of miR-9-5p/Fstl1 axis in survival defense against hypoxic challenge. In summary, these findings identified miR-9-5p as a mediator of hypoxic injury in cardiomyoblasts and miR-9-5p suppression prevents cardiac remodeling after acute MI, providing a potential strategy for early treatment against MI.

Epigenetics of inflammatory arthritis

PURPOSE OF REVIEW

Aberrant epigenetic changes in DNA methylation, histone marks, and noncoding RNA expression regulate the pathogenesis of many rheumatic diseases. The present article will review the recent advances in the epigenetic profile of inflammatory arthritis and discuss diagnostic biomarkers and potential therapeutic targets.

RECENT FINDINGS

Methylation signatures of fibroblast-like synoviocytes not only distinguish rheumatoid arthritis (RA) and osteoarthritis (OA), but also early RA from late RA or juvenile idiopathic arthritis. Methylation patterns are also specific to individual joint locations, which might explain the distribution of joint involvement in some rheumatic diseases. Hypomethylation in systemic lupus erythematosus (SLE) T cells is, in part, because of active demethylation and 5-hydroxymethylation. The methylation status of some genes in SLE is associated with disease severity and has potential as a diagnostic marker. An integrative analysis of OA methylome, transcriptome, and proteome in chondrocytes has identified multiple-evidence genes that might be evaluated for therapeutic potential. Class-specific histone deacetylase inhibitors are being evaluated for therapy in inflammatory arthritis.

SUMMARY

Disease pathogenesis is regulated by the interplay of genetics, environment, and epigenetics. Understanding how these mechanisms regulate cell function in health and disease has implications for individualized therapy.

Deficiency of Follistatin-Like Protein 1 Accelerates the Growth of Breast Cancer Cells at Lung Metastatic Sites

Purpose

Follistatin-like protein 1 (FSTL1) is a secreted glycoprotein that has been shown to play a role in various types of cancer. However, the clinical significance and function of FSTL1 in breast cancer have not been reported. We investigated the role of FSTL1 in breast cancer in this study.

Methods

Enzyme-linked immunosorbent assays, western blot analysis, and reverse transcription polymerase chain reaction were used to monitor the expression of FSTL1 in breast cancer tissue and in serum samples from breast cancer patients. We employed a 4T1 breast cancer model and Fstl1 ^+/- mice for in vivo studies. Hematoxylin and eosin staining, western blot analysis, and RNA sequencing were used to analyze the effect of FSTL1 on primary tumor growth and lung metastasis.

Results

We demonstrated that the expression of FSTL1 is reduced in both the breast cancer tissue and the serum of breast cancer patients. We showed that reduced levels of FSTL1 in serum correlate with elevated expression of Ki-67 and epidermal growth factor receptor (EGFR) in cancer tissues. Moreover, lowered expression of FSTL1 was associated with decreased survival in breast cancer patients. Experiments on the Fstl1 ^+/- mouse model established that FSTL1 deficiency had no effect on primary tumor growth, but increased the lung metastases of breast cancer cells, resulting in reduced survival of tumor-bearing mice. RNA sequencing found significantly reduced expression of Egln3 and increased expression of EGFR in Fstl1 ^+/- mice. Thus, our results suggest that FSTL1 may affect the expression of EGFR through Egln3, inhibiting the proliferation of breast cancer cells at lung metastatic sites.

Conclusion

In conclusion, we suggest a suppressor role of FSTL1 in breast cancer lung metastasis. Furthermore, FSTL1 may represent a potential prognostic biomarker and a candidate therapeutic target in breast cancer patients.

MicroRNA-27a alleviates LPS-induced acute lung injury in mice via inhibiting inflammation and apoptosis through modulating TLR4/MyD88/NF-κB pathway

Acute lung injury (ALI) is a critical clinical condition with a high mortality rate, characterized with excessive uncontrolled inflammation and apoptosis. Recently, microRNAs (miRNAs) have been found to play crucial roles in the amelioration of various inflammation-induced diseases, including ALI. However, it remains unknown the biological function and regulatory mechanisms of miRNAs in the regulation of inflammation and apoptosis in ALI. The aim of this study is to identify and evaluate the potential role of miRNAs in ALI and reveal the underlying molecular mechanisms of their effects. Here, we analyzed microRNA expression profiles in lung tissues from LPS-challenged mice using miRNA microarray. Because microRNA-27a (miR-27a) was one of the miRNAs being most significantly downregulated, which has an important role in regulation of inflammation, we investigated its function. Overexpression of miR-27a by agomir-27a improved lung injury, as evidenced by the reduced histopathological changes, lung wet/dry (W/D) ratio, lung microvascular permeability and apoptosis in the lung tissues, as well as ameliorative survival of ALI mice. This was accompanied by the alleviating of inflammation, such as the reduced total BALF cell and neutrophil counts, decreased levels of tumor necrosis factor alpha (TNF-α), interleukin-1 (IL-6) interleukin-1β (IL-1β) and myeloperoxidase (MPO) activity in BAL fluid. Toll-like receptor 4 (TLR4), an important regulator of the nuclear factor kappa-B (NF-κB) signaling pathway, was identified as a novel target of miR-27a in RAW264.7 cells. Furthermore, our results showed that LPS stimulation increased the expression of MyD88 and NF-κB p65 (p-p65), but inhibited the expression of inhibitor of nuclear factor-κB-α (IκB-α), suggesting the activation of NF-κB signaling pathway. Further investigations revealed that agomir-miR-27a reversed the promoting effect of LPS on NF-κB signaling pathway. The results here suggested that miR-27a alleviates LPS-induced ALI in mice via reducing inflammation and apoptosis through blocking TLR4/MyD88/NF-κB activation.

The Micro-RNA Expression Profiles of Autoimmune Arthritis Reveal Novel Biomarkers of the Disease and Therapeutic Response

Rheumatoid arthritis (RA) is a chronic autoimmune disease of the joints affecting about 0.3–1% of the population in different countries. About 50–60 percent of RA patients respond to presently used drugs. Moreover, the current biomarkers for RA have inherent limitations. Consequently, there is a need for additional, new biomarkers for monitoring disease activity and responsiveness to therapy of RA patients. We examined the micro-RNA (miRNA) profile of immune (lymphoid) cells of arthritic Lewis rats and arthritic rats treated with celastrol, a natural triterpenoid. Experimental and bioinformatics analyses revealed 8 miRNAs (miR-22, miR-27a, miR-96, miR-142, miR-223, miR-296, miR-298, and miR-451) and their target genes in functional pathways important for RA pathogenesis. Interestingly, 6 of them (miR-22, miR-27a, miR-96, miR-142, miR-223, and miR-296) were further modulated by celastrol treatment. Interestingly, serum levels of miR-142, miR-155, and miR-223 were higher in arthritic versus control rats, whereas miR-212 showed increased expression in celastrol-treated rats compared with arthritic rats or control rats. This is the first study on comprehensive miRNA expression profiling in the adjuvant-induced arthritis (AA) model and it also has revealed new miRNA targets for celastrol in arthritis. We suggest that subsets of the above miRNAs may serve as novel biomarkers of disease activity and therapeutic response in arthritis.

Follistatin-like 1 in development and human diseases

Follistatin-like 1 (FSTL1) is a secreted glycoprotein displaying expression changes during development and disease, among which cardiovascular disease, cancer, and arthritis. The cardioprotective role of FSTL1 has been intensively studied over the last years, though its mechanism of action remains elusive. FSTL1 is involved in multiple signaling pathways and biological processes, including vascularization and regulation of the immune response, a feature that complicates its study. Binding to the DIP2A, TLR4 and BMP receptors have been shown, but other molecular partners probably exist. During cancer progression and rheumatoid arthritis, controversial data have been reported with respect to the proliferative, apoptotic, migratory, and inflammatory effects of FSTL1. This controversy might reside in the extensive post-transcriptional regulation of FSTL1. The FSTL1 primary transcript also encodes for a microRNA (miR-198) in primates and multiple microRNA-binding sites are present in the 3'UTR. The switch between expression of the FSTL1 protein and miR-198 is an important regulator of tumour metastasis and wound healing. The glycosylation state of FSTL1 is a determinant of biological activity, in cardiomyocytes the glycosylated form promoting proliferation and the non-glycosylated working anti-apoptotic. Moreover, the glycosylation state shows differences between species and tissues which might underlie the differences observed in in vitro studies. Finally, regulation at the level of protein secretion has been described.

The Effects of MicroRNAs on Key Signalling Pathways and Epigenetic Modification in Fibroblast-Like Synoviocytes of Rheumatoid Arthritis

MicroRNAs (miRNAs) are small noncoding RNAs that regulate gene expression at the posttranscriptional level via direct binding to the 3′-untranslated region (UTR) of target mRNAs. Emerging evidence shows that miRNAs play crucial roles in controlling and modulating immune system-related diseases. This review focuses on the role played by miRNAs in fibroblast-like synoviocytes (FLS), which is a key cellular component within synovia, during the establishment and maintenance of rheumatoid arthritis (RA), a systemic inflammatory autoimmune disease. It also provides an overview and classification of known functional miRNAs in RA FLS and summarizes the potential uses of these small molecules in RA diagnosis and treatment.

Dysregulation of microRNAs in autoimmune diseases: Pathogenesis, biomarkers and potential therapeutic targets

MicroRNAs (miRNAs) are small, single-stranded, endogenous non-coding RNAs that repress the expression of target genes via post-transcriptional mechanisms. Due to their broad regulatory effects, the precisely regulated, spatial-specific and temporal-specific expression of miRNAs is fundamentally important to various biological processes including the immune homeostasis and normal function of both innate and adaptive immune response. Aberrance of miRNAs is implicated in the development of various human diseases, especially cancers. Increasing evidence has revealed a dysregulated expression pattern of miRNAs in autoimmune diseases, among which many play key roles in the pathogenesis. In this review we summarize these findings on miRNA dysregulation implicated in autoimmune diseases, focusing on four representative systemic autoimmune diseases, i.e. systemic lupus erythematosus, rheumatoid arthritis, systemic sclerosis and dermatomyositis. The causes of the dysregulation of miRNA expression in autoimmune diseases may include genetic and epigenetic variants, and various environmental factors. Further understanding of miRNA dysregulation and its mechanisms during the development of different autoimmune diseases holds enormous potential to bring about novel therapeutic targets or strategies for these complex human disorders, as well as novel circulating or exosomal miRNA biomarkers.

An OMIC biomarker detection algorithm TriVote and its application in methylomic biomarker detection

Aim: Transcriptomic and methylomic patterns represent two major OMIC data sources impacted by both inheritable genetic information and environmental factors, and have been widely used as disease diagnosis and prognosis biomarkers. Materials & methods: Modern transcriptomic and methylomic profiling technologies detect the status of tens of thousands or even millions of probing residues in the human genome, and introduce a major computational challenge for the existing feature selection algorithms. This study proposes a three-step feature selection algorithm, TriVote, to detect a subset of transcriptomic or methylomic residues with highly accurate binary classification performance. Results & conclusion: TriVote outperforms both filter and wrapper feature selection algorithms with both higher classification accuracy and smaller feature number on 17 transcriptomes and two methylomes. Biological functions of the methylome biomarkers detected by TriVote were discussed for their disease associations. An easy-to-use Python package is also released to facilitate the further applications.

Monocyte-related biomarkers of rheumatoid arthritis development in undifferentiated arthritis patients - a pilot study

Objectives

Enhanced/disturbed activities of monocytes are crucial for perpetuation and for development of rheumatoid arthritis (RA). Therefore, knowledge about monocyte activities and regulation of molecular pathways operating within monocytes early in the course of RA development may help to predict the progression to the full-blown disease. We aimed to investigate the profile of miRNAs expression in circulating monocytes and monocyte-related cytokines in sera of individuals at undifferentiated arthritis (UA) stage, wich could serve as new biomarkers for RA development.

Material and methods

Magnetically sorted monocytes from peripheral blood of 20 UA patients served for total RNA isolation. RNA samples were used for microRNA profiling. Concentrations of CCL3/MIP-1α, M-CSF, CCL2/MCP-1, IL-6, TNF-α and IL-15 in sera of UA patients were measured using ELISA assays. Verification of diagnosis after 4 years of follow-up led to the identification of patients who developed RA (UA→RA patients) and patients who remained still in UA phase (UA → UA patients). Comparisons between patients groups were performed using two-tailed Mann-Whitney U test.

Results

We identified 50 miRNAs in monocytes with the largest variation of expression across all patients samples. From these selected miRNAs, expression of miR-642b-5p, miR-483-3p, miR-371b-5p were significantly up-regulated and miR-25-3p and miR-378d were significantly down-regulated in UA → RA vs. UA → UA patients. This specific pattern of miRNAs expression in circulating monocytes paralleled elevated IL-15 and M-CSF concentrations in sera of UA patients who progressed to RA.

Conclusions

Results of our pilot study indicate that altered activity of monocytes can be detected at early stages of RA. We found new miRNA candidates differentially expressed in peripheral blood monocytes and elevated concentrations of IL-15 and M-CSF involved in monocyte activity and differentiation in patients with UA who subsequently developed RA, in comparison to UA patients who did not progress to RA after 4 years follow-up.

Plasma MicroRNA Profiles in Patients with Early Rheumatoid Arthritis Responding to Adalimumab plus Methotrexate vs Methotrexate Alone: A Placebo-controlled Clinical Trial

OBJECTIVE

The aim was to identify plasma (i.e., cell-free) microRNA (miRNA) predicting antitumor necrosis and/or methotrexate (MTX) treatment response in patients enrolled in an investigator-initiated, prospective, double-blinded, placebo-controlled trial (The OPERA study, NCT00660647).

METHODS

We included 180 disease-modifying antirheumatic drug-naive patients with early rheumatoid arthritis (RA) randomized to adalimumab (ADA; n = 89) or placebo (n = 91) in combination with MTX. Plasma samples before and 3 months after treatment initiation were analyzed for 91 specific miRNA by quantitative reverse transcriptase-polymerase chain reaction on microfluidic dynamic arrays. A linear mixed-effects model was used to test for associations between pretreatment miRNA and changes in miRNA expression and American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) Boolean (28 joints) remission at 3 and 12 months, applying false discovery rate correction for multiple testing. Using leave-one-out cross validation, we built predictive multivariate miRNA models and estimated classification performances using receiver-operating characteristics (ROC) curves.

RESULTS

In the ADA group, a higher pretreatment level of miR-27a-3p was significantly associated with remission at 12 months. The level decreased in remitting patients between pretreatment and 3 months, and increased in nonremitting patients. No associations were found in the placebo group receiving only MTX. Two multivariate miRNA models were able to predict response to ADA treatment after 3 and 12 months, with 63% and 82% area under the ROC curves, respectively.

CONCLUSION

We identified miR-27a-3p as a potential predictive biomarker of ACR/EULAR remission in patients with early RA treated with ADA in combination with MTX. We conclude that pretreatment plasma-miRNA profiles may be of predictive value, but the results need confirmation in independent cohorts.

FSTL1 Promotes Metastasis and Chemoresistance in Esophageal Squamous Cell Carcinoma through NFκB-BMP Signaling Cross-talk

Esophageal squamous cell carcinoma (ESCC) has a generally poor prognosis, and molecular markers to improve early detection and predict outcomes are greatly needed. Here, we report that the BMP-binding follistatin-like protein FSTL1 is overexpressed in ESCCs, where it correlates with poor overall survival. Genetic amplification of FSTL1 or chromosome 3q, where it is located, occurred frequently in ESCC, where FSTL1 copy number correlated positively with higher FSTL1 protein expression. Elevating FSTL1 levels by various means was sufficient to drive ESCC cell proliferation, clonogenicity, migration, invasion, self-renewal, and cisplatin resistance in vitro and tumorigenicity and distant metastasis in vivo Conversely, FSTL1 attenuation by shRNA or neutralizing antibody elicited the opposite effects in ESCC cells. mRNA profiling analyses suggested that FSTL1 drives ESCC oncogenesis and metastasis through various pathways, with deregulation of NFκB and BMP signaling figuring prominently. Cross-talk between the NFκB and BMP pathways was evidenced by functional rescue experiments using inhibitors of NFκB and TLR4. Our results establish the significance of FSTL1 in driving oncogenesis and metastasis in ESCC by coordinating NFκB and BMP pathway control, with implications for its potential use as a diagnostic or prognostic biomarker and as a candidate therapeutic target in this disease setting. Cancer Res; 77(21); 5886-99. ©2017 AACR.

LncRNA ZFAS1 promotes cell migration and invasion of fibroblast-like synoviocytes by suppression of miR-27a in rheumatoid arthritis

Rheumatoid arthritis (RA) is a systemic and chronic inflammatory disease. Synoviocyte migration and invasion were found to be essential to the pathology of RA. Upregulation of long noncoding RNA ZFAS1 has been observed in cancers and promotes cell migration and invasion. To date, the functions and mechanisms of ZFAS1 in RA have not been revealed. In this study, we analyzed expression pattern of ZFAS1 in RA patients and found that ZFAS1 expression was increased in synovial tissue and fibroblast-like synoviocytes (FLS) from RA patients (RA-FLS) compared with that in healthy donors. Functional assays showed that silence of ZFAS1 suppressed RA-FLS migration and invasion, while overexpression of ZFAS1 showed the opposite effect. Further investigation demonstrated that ZFAS1 directly interacted with miR-27a and decreased miR-27a expression. ZFAS1 promotes RA-FLS migration and invasion in an miR-27a-dependent manner. Taken together, the present study provides the first evidence that ZFAS1 promotes cell migration and invasion through miR-27a in RA-FLS, suggesting that ZFAS1 may be an effective therapeutic target for RA patients.

TLR-4/miRNA-32-5p/FSTL1 signaling regulates mycobacterial survival and inflammatory responses in Mycobacterium tuberculosis-infected macrophages

Macrophages play a pivotal role in host immune response against mycobacterial infection, which is tightly modulated by multiple factors, including microRNAs. The purpose of the present study was to investigate the biological function and potential mechanism of miR-32-5p in human macrophages during Mycobacterium tuberculosis (M.tb) infection. The results demonstrated that miR-32-5p was robustly enhanced in THP-1 and U937 cells in response to M.tb infection. TLR-4 signaling was required for upregulation of miR-32-5p induced by M.tb infection. Additionally, the introduction of miR-32-5p strongly increased the survival rate of intracellular mycobacteria, whereas inhibition of miR-32-5p suppressed intracellular growth of mycobacteria during M.tb challenged. Furthermore, forced expression of miR-32-5p dramatically attenuated the accumulation of inflammatory cytokines IL-1β, IL-6 and TNF-α induced by M.tb infection. Conversely, downregulated expression of miR-32-5p led to enhancement in these inflammatory cytokines. More importantly, our study explored that Follistatin-like protein 1 (FSTL1) was a direct and functional target of miR-32-5p. qRT-PCR and western blot analysis further validated that miR-32-5p negatively regulated the expression of FSTL1. Mechanistically, re-expression of FSTL1 attenuated the ability of miR-32-5p to promote mycobacterial survival. Meanwhile, miR-32-5p-mediated inhibition of the inflammatory cytokine production were completely reversed by overexpression of FSTL1. Collectively, our findings demonstrated a novel role of TLR-4/miRNA-32-5p/FSTL1 in the modulation of host defense against mycobacterial infection, which may provide a better understanding of the pathogenesis of tuberculosis and useful information for developing potential therapeutic interventions against the disease.

The influence of fibroblast on the arachnoid leptomeningeal cells in vitro

OBJECTIVE

Fibroblast is pervasive in the setting of injury. Its invasion into the arachnoid tissue causes scarring, cortical adhesion of the brain, and obstruction of cerebrospinal fluid outflow. The purpose of this study is to determine the phenotypic and physiologic effects of fibroblasts on arachnoid in culture.

METHODS

We studied the effects of fibroblast on the arachnoid cell growth, motility, phenotypic changes, and transport properties. Immortalized rat (Rattus norvegicus, Sprague Dawley breed) arachnoid cells were grown with fibroblast on opposite sides of polyethylene membranes or co-cultured in plastic wells. Arachnoid cell growth rate and DNA content, morphology, transport physiology, and extracellular matriceal content were determined in the presence of normal and irradiated fibroblast cells.

RESULTS

When arachnoid cells were grown in the presence of fibroblasts, mannitol permeability increased and transepithelial electrical resistance (TEER) decreased. Arachnoid cell growth rate also significantly decreased. When arachnoid cells were grown in close proximity (i.e. on the same monolayer) with fibroblasts, the arachnoid cells were overrun by day 2, yet when physically separated, no significant change was seen in growth. Apoptosis increased markedly in arachnoid cultures in the presence of fibroblast. Fibroblast caused arachnoid cell to exhibit avoidance behavior, and irradiated fibroblast induced arachnoidal cells to move faster and exhibited greater directional changes. Subcellular glycosaminoglycan (GAG) content was significantly altered by fibroblast.

INTERPRETATION

Fibroblasts influence arachnoid cell's mannitol transport likely via soluble factors. While the arachnoid cells did not change morphologically, cell growth was influenced. Over time, the cells had profound changes in transport and motility. The immortalized arachnoid cell/fibroblast culture system provides a unique model mimicking the pathologic event of leptomeningeal scarring.