NF-κB-dependent microRNA-125b up-regulation promotes cell survival by targeting p38α upon ultraviolet radiation

Baicalin inhibits the replication of the hepatitis B virus by targeting TRIM25

Objective

Baicalin, which is a key bioactive constituent obtained from Scutellaria baicalensis, has been utilized in traditional Chinese medicine for many centuries. Although it has been reported that Baicalin (BA) can inhibit the replication of the Hepatitis B virus (HBV), the exact mechanism behind this process remains unclear. Interferon-stimulated genes (ISGs) are crucial in the process of antiviral defense. We aim to investigate whether BA can regulate the expression of ISGs, and thereby potentially modulate the replication of HBV.

Methods

The study involved the use of CRISPR/Cas9 technology to perform knockout experiments on TRIM25 and IFIT3 genes. The expression of these genes was confirmed through techniques such as immunoblotting or Q-PCR. The levels of HBsAg and HBeAg were measured using ELISA, and the expression of interferon-stimulated genes was detected using a luciferase assay.

Results

It is interesting to note that several ISGs belonging to the TRIM family, including TRIM5, TRIM25, and TRIM14, were induced after BA treatment. On the other hand, members of the IFIT family were reduced by BA stimulation. Additionally, BA-mediated HBV inhibition was found to be significantly restored in HepG2 cells where TRIM25 was knocked out. Additional research into the mechanism of action of BA found that prolonged treatment with BA activated the JAK/STAT signaling pathway while simultaneously inhibiting the NF-kB pathway.

Conclusion

The findings of our study indicate that TRIM25 has a significant impact on the regulation of HBV replication following BA treatment, providing additional insight into the mechanisms by which BA exerts its antiviral effects.

The microRNA-7322-5p/p38/Hsp19 axis modulates Chilo suppressalis cell-defences against Cry1Ca: an effective target for a stacked transgenic rice approach

Bacillus thuringiensis (Bt)-secreted crystal (Cry) toxins form oligomeric pores in host cell membranes and are a common element in generating insect-resistant transgenic crops. Although Cry toxin function has been well documented, cellular defences against pore-formation have not been as well developed. Elucidation of the processes underlying this defence, however, could contribute to the development of enhanced Bt crops. Here, we demonstrate that Cry1Ca-mediated downregulation of microRNA-7322-5p (miR-7322-5p), which binds to the 3' untranslated region of p38, negatively regulates the susceptibility of Chilo suppressalis to Cry1Ca. Moreover, Cry1Ca exposure enhanced phosphorylation of Hsp19, and hsp19 downregulation increased susceptibility to Cry1Ca. Further, Hsp19 phosphorylation occurs downstream of p38, and pull-down assays confirmed the interactions between Hsp19 and Cry1Ca, suggesting that activation of Hsp19 by the miR-7322-5p/p38/Hsp19 pathway promotes Cry1Ca sequestration. To assess the efficacy of targeting this pathway in planta, double-stranded RNA (dsRNA) targeting C. suppressalis p38 (dsp38) was introduced into a previously generated cry1Ca-expressing rice line (1CH1-2) to yield a single-copy cry1Ca/dsp38 rice line (p38-rice). Feeding on this rice line triggered a significant reduction in C. suppressalis p38 expression and the line was more resistant to C. suppressalis than 1CH1-2 in both short term (7-day) and continuous feeding bioassays as well as field trials. These findings provide new insights into invertebrate epithelium cellular defences and demonstrate a potential new pyramiding strategy for Bt crops.

Current concepts of microRNA-mediated regulatory mechanisms in human pulp tissue-derived stem cells: a snapshot in the regenerative dentistry

One of the most studied class of non-coding RNAs is microRNAs (miRNAs) which regulate more than 60% of human genes. A network of miRNA gene interactions participates in stem cell self-renewal, proliferation, migration, apoptosis, immunomodulation, and differentiation. Human pulp tissue-derived stem cells (PSCs) are an attractive source of dental mesenchymal stem cells (MSCs) which comprise human dental pulp stem cells (hDPSCs) obtained from the dental pulp of permanent teeth and stem cells isolated from exfoliated deciduous teeth (SHEDs) that would be a therapeutic opportunity in stomatognathic system reconstruction and repair of other damaged tissues. The regenerative capacity of hDPSCs and SHEDs is mediated by osteogenic, odontogenic, myogenic, neurogenic, angiogenic differentiation, and immunomodulatory function. Multi-lineage differentiation of PSCs can be induced or inhibited by the interaction of miRNAs with their target genes. Manipulating the expression of functional miRNAs in PSCs by mimicking miRNAs or inhibiting miRNAs emerged as a therapeutic tool in the clinical translation. However, the effectiveness and safety of miRNA-based therapeutics, besides higher stability, biocompatibility, less off-target effects, and immunologic reactions, have received particular attention. This review aimed to comprehensively overview the molecular mechanisms underlying miRNA-modified PSCs as a futuristic therapeutic option in regenerative dentistry.

Type-III interferon stimulated gene TRIM31 mutation in an HBV patient blocks its ability in promoting HBx degradation

TRIM5γ, together with TRIM31, has been shown to promote HBx ubiquitination and degradation. This study aimed to explore whether a patient with HCC (hepatic cell carcinoma) having a small nucleotide inserted into the TRIM31 gene, which made a shorter transcript stop at 768 bp, would result in blocking the activity of TRIM31 in promoting HBx degradation. Besides, this study aimed to determine the binding region of the TRIM31-TRIM5γ-HBx complex. HBV (Hepatitis B virus) infection was reported to induce type-III IFN but not type-I or type-II IFNs, here TRIM31 was found to be a type III rather than a type I stimulated gene, which was indispensable in inhibiting the hepatitis B virus replication by the interferon families. Thus, this study further identified the critical role of TRIM31 in the host-hepatitis B virus interaction.

MK2 degradation as a sensor of signal intensity that controls stress-induced cell fate

Cell survival in response to stress is determined by the coordination of various signaling pathways. The kinase p38α is activated by many stresses, but the intensity and duration of the signal depends on the stimuli. How different p38α-activation dynamics may impact cell life/death decisions is unclear. Here, we show that the p38α-signaling output in response to stress is modulated by the expression levels of the downstream kinase MK2. We demonstrate that p38α forms a complex with MK2 in nonstimulated mammalian cells. Upon pathway activation, p38α phosphorylates MK2, the complex dissociates, and MK2 is degraded. Interestingly, transient p38α activation allows MK2 reexpression, reassembly of the p38α-MK2 complex, and cell survival. In contrast, sustained p38α activation induced by severe stress interferes with p38α-MK2 interaction, resulting in irreversible MK2 loss and cell death. MK2 degradation is mediated by the E3 ubiquitin ligase MDM2, and we identify four lysine residues in MK2 that are directly ubiquitinated by MDM2. Expression of an MK2 mutant that cannot be ubiquitinated by MDM2 enhances the survival of stressed cells. Our results indicate that MK2 reexpression and binding to p38α is critical for cell viability in response to stress and illustrate how particular p38α-activation patterns induced by different signals shape the stress-induced cell fate.

microRNA-210 and microRNA-3570 Negatively Regulate NF-κB-Mediated Inflammatory Responses by Targeting RIPK2 in Teleost Fish

Pathogen infection can cause the production of inflammatory cytokines, which are key mediators that cause the host’s innate immune response. Therefore, proper regulation of immune genes associated with inflammation is essential for immune response. Among them, microRNAs (miRNAs) as gene regulator have been widely reported to be involved in the innate immune response of mammals. However, the regulatory network in which miRNAs are involved in the development of inflammation is largely unknown in lower vertebrates. Here, we identified two miRNAs from miiuy croaker (Miichthys miiuy), miR-210 and miR-3570, which play a negative regulatory role in host antibacterial immunity. We found that the expressions of miR-210 and miR-3570 were significantly upregulated under the stimulation of Gram-negative bacterium vibrio harveyi and LPS (lipopolysaccharide). Induced miR-210 and miR-3570 inhibit inflammatory cytokine production by targeting RIPK2, thereby avoiding excessive inflammation. In particular, we found that miR-210 and miR-3570 negatively regulate antimicrobial immunity by regulating the RIPK2-mediated NF-κB signaling pathway. The collective results indicated that both miRNAs are used as negative feedback regulators to regulate RIPK2-mediated NF-κB signaling pathway and thus play a regulatory role in bacteria-induced inflammatory response.

UVA influenced the SIRT1-miR-27a-5p-SMAD2-MMP1/COL1/BCL2 axis in human skin primary fibroblasts

Both SIRT1 and UVA radiation are involved in cellular damage processes such as apoptosis, senescence and ageing. MicroRNAs (miRNAs) have been reported to be closely related to UV radiation, as well as to SIRT1. In this study, we investigated the connections among SIRT1, UVA and miRNA in human skin primary fibroblasts. Our results showed that UVA altered the protein level of SIRT1 in a time point–dependent manner. Using miRNA microarray, bioinformatics analysis, we found that knocking down SIRT1 could cause up‐regulation of miR‐27a‐5p and the latter could down‐regulate SMAD2, and these results were verified by qRT‐PCR or Western blot. Furthermore, UVA radiation (5 J/cm²), knocking down SIRT1 or overexpression of miR‐27a‐5p led to increased expression of MMP1, and decreased expressions of COL1 and BCL2. We also found additive impacts on MMP1, COL1 and BCL2 under the combination of UVA radiation + Sirtinol (SIRT1 inhibitor), or UVA radiation + miR‐27a‐5p mimic. SIRT1 activator resveratrol could reverse damage changes caused by UVA radiation. Besides, absent of SIRT1 or overexpression of miR‐27a‐5p increased cell apoptosis and induced cell arrest in G2/M phase. Taken together, these results demonstrated that UVA could influence a novel SIRT1‐miR‐27a‐5p‐SMAD2‐MMP1/COL1/BCL2 axis in skin primary fibroblasts, and may provide potential therapeutic targets for UVA‐induced skin damage.

Effects of Mycoplasmas on the Host Cell Signaling Pathways

Mycoplasmas are the smallest free-living organisms. Reduced sizes of their genomes put constraints on the ability of these bacteria to live autonomously and make them highly dependent on the nutrients produced by host cells. Importantly, at the organism level, mycoplasmal infections may cause pathological changes to the host, including cancer and severe immunological reactions. At the molecular level, mycoplasmas often activate the NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) inflammatory response and concomitantly inhibit the p53-mediated response, which normally triggers the cell cycle and apoptosis. Thus, mycoplasmal infections may be considered as cancer-associated factors. At the same time, mycoplasmas through their membrane lipoproteins (LAMPs) along with lipoprotein derivatives (lipopeptide MALP-2, macrophage-activating lipopeptide-2) are able to modulate anti-inflammatory responses via nuclear translocation and activation of Nrf2 (the nuclear factor-E2-related anti-inflammatory transcription factor 2). Thus, interactions between mycoplasmas and host cells are multifaceted and depend on the cellular context. In this review, we summarize the current information on the role of mycoplasmas in affecting the host’s intracellular signaling mediated by the interactions between transcriptional factors p53, Nrf2, and NF-κB. A better understanding of the mechanisms underlying pathologic processes associated with reprogramming eukaryotic cells that arise during the mycoplasma-host cell interaction should facilitate the development of new therapeutic approaches to treat oncogenic and inflammatory processes.

Implication of the p53-Related miR-34c, -125b, and -203 in the Osteoblastic Differentiation and the Malignant Transformation of Bone Sarcomas

The formation of the skeleton occurs throughout the lives of vertebrates and is achieved through the balanced activities of two kinds of specialized bone cells: the bone-forming osteoblasts and the bone-resorbing osteoclasts. Impairment in the remodeling processes dramatically hampers the proper healing of fractures and can also result in malignant bone diseases such as osteosarcoma. MicroRNAs (miRNAs) are a class of small non-coding single-strand RNAs implicated in the control of various cellular activities such as proliferation, differentiation, and apoptosis. Their post-transcriptional regulatory role confers on them inhibitory functions toward specific target mRNAs. As miRNAs are involved in the differentiation program of precursor cells, it is now well established that this class of molecules also influences bone formation by affecting osteoblastic differentiation and the fate of osteoblasts. In response to various cell signals, the tumor-suppressor protein p53 activates a huge range of genes, whose miRNAs promote genomic-integrity maintenance, cell-cycle arrest, cell senescence, and apoptosis. Here, we review the role of three p53-related miRNAs, miR-34c, -125b, and -203, in the bone-remodeling context and, in particular, in osteoblastic differentiation. The second aim of this study is to deal with the potential implication of these miRNAs in osteosarcoma development and progression.

MicroRNA-125a-3p participates in odontoblastic differentiation of dental pulp stem cells by targeting Fyn

Fyn is a member of the protein tyrosine kinase family and its overexpression is associated with various types of inflammation. MicroRNAs can regulate the expression of target genes and play an important role in varied physiological and pathological processes. Based on the important role of Fyn and microRNA-125a-3p (miR-125a-3p) in inflammation, and combined with the bioinformatics studies, we performed in this study and chose miR-125a-3p as the focus of our research. During the progression of inflammation, we found that the expression of miR-125a-3p was decreased while the expression of Fyn was up-regulated. Fyn formed a complex with Neuropilin-1, which inhibited odontoblastic differentiation and expanded inflammatory responses through nuclear factor-κB signal pathways in dental pulp stem cells (DPSCs). These findings suggested that miR-125a-3p plays an important role in odontoblastic differentiation of DPSCs by targeting Fyn, implying its therapeutic potential in dental caries.

NF-κB-Dependent IFIT3 Induction by HBx Promotes Hepatitis B Virus Replication

Therapeutic administration of type I IFN (IFN-I) is a common treatment option for individuals suffering from hepatitis B virus (HBV) infection. IFN-I therapy, however, has a relatively low response rate in HBV-infected patients and can induce serious side-effects, limiting its clinical efficacy. There is, thus, a clear need to understand the molecular mechanisms governing the influence of IFN-I therapy in HBV treatment in order to improve patient outcomes. In this study, we explored the interactions between HBV and IFITs (IFN-induced proteins with tetratricopeptide repeats), which are classical IFN-inducible genes. Specifically, we found that HBV patients undergoing IFN-I therapy exhibited elevated expression of IFITs in their peripheral blood mononuclear cells (PBMCs). We further observed upregulation in the expressions of IFIT1, IFIT2, and IFIT3 in cells transfected with the pHBV1.3 plasmid, which yields infectious virions in hepatic cells. We additionally found that HBx, which is the only regulatory protein encoded within the HBV genome, activates NF-κB, which in turn directly drives IFIT3 transcription. When IFIT3 was overexpressed in HepG2 cells, HBV replication was enhanced. Together, these results suggest that IFIT genes may unexpectedly enhance viral replication, thus making these genes potential therapeutic targets in patients with HBV.

Dysregulation of miR-125b predicts poor response to therapy in pediatric acute lymphoblastic leukemia

BACKGROUND

Acute lymphoblastic leukemia (ALL) is the most well-known sort of leukemia in children. In spite of favorable survival rates, some patients relapse and achieve a poor outcome.

METHODS

We analyzed miR-125b and Bcl-2 expressions in pediatric patients with ALL and evaluated their clinical utility as molecular markers for the prediction of disease outcomes.

RESULTS

Downregulation of miR-125b and increased Bcl-2 expression levels in pediatric patients with ALL were associated with poor prognosis at diagnosis. At day 28 of induction, miR-125b was significantly increased, whereas Bcl-2 was downregulated. Loss of miR-125b during diagnosis and its elevation after therapy are strongly correlated with short leukemia-free survival and worse survival. Moreover, the combination of miR-125b with Bcl-2 markers can clearly enhance the prediction of the disease outcome. Finally, a univariate analysis highlighted the independent prognostic value of miR-125 in a pediatric patient with ALL.

CONCLUSIONS

miR-125b and Bcl-2 together are potent predictors for the prognosis and, therefore, can be used as therapeutic targets in childhood ALL.

Hepatitis B Virus-Induced Imbalance of Inflammatory and Antiviral Signaling by Differential Phosphorylation of STAT1 in Human Monocytes

It is not clear how hepatitis B virus (HBV) modulates host immunity during chronic infection. In addition to the key mediators of inflammatory response in viral infection, monocytes also express a high-level IFN-stimulated gene, CH25H, upon response to IFN-α exerting an antiviral effect. In this study, the mechanism by which HBV manipulates IFN signaling in human monocytes was investigated. We observed that monocytes from chronic hepatitis B patients express lower levels of IFN signaling/stimulated genes and higher levels of inflammatory cytokines compared with healthy donors. HBV induces monocyte production of inflammatory cytokines via TLR2/MyD88/NF-κB signaling and STAT1-Ser727 phosphorylation and inhibits IFN-α-induced stat1, stat2, and ch25h expression through the inhibition of STAT1-Tyr701 phosphorylation and in an IL-10-dependent, partially autocrine manner. Further, we found that enhancement of STAT1 activity with a small molecule (2-NP) rescued HBV-mediated inhibition of IFN signaling and counteracted the induction of inflammatory cytokines. In conclusion, HBV contributes to the monocyte inflammatory response but inhibits their IFN-α/β responsiveness to impair antiviral innate immunity. These effects are mediated via differential phosphorylation of Tyr701 and Ser727 of STAT1.

Upregulation of PD-L1 via HMGB1-Activated IRF3 and NF-κB Contributes to UV Radiation-Induced Immune Suppression

Solar ultraviolet radiation (UVR) suppresses skin immunity, which facilitates initiation of skin lesions and establishment of tumors by promoting immune evasion. It is unclear whether immune checkpoints are involved in the modulation of skin immunity by UVR. Here, we report that UVR exposure significantly increased expression of immune checkpoint molecule PD-L1 in melanoma cells. The damage-associated molecular patterns molecule HMGB1 was secreted by melanocytes and keratinocytes upon UVR, which subsequently activated the receptor for advanced glycation endproducts (RAGE) receptor to promote NF-κB- and IRF3-dependent transcription of PD-L1 in melanocytes. UVR exposure significantly reduced the susceptibility of melanoma cells to CD8⁺ T-cell-dependent cytotoxicity, which was mitigated by inhibiting the HMGB1/TBK1/IRF3/NF-κB cascade or by blocking the PD-1/PD-L1 checkpoint. Taken together, our findings demonstrate that UVR-induced upregulation of PD-L1 contributes to immune suppression in the skin microenvironment, which may promote immune evasion of oncogenic cells and drive melanoma initiation and progression. SIGNIFICANCE: These findings identify PD-L1 as a critical component of UV-induced immune suppression in the skin, which facilitates immunoevasion of oncogenic melanocytes and development of melanoma.See related commentary by Sahu, p. 2805.

Vascular smooth muscle-MAPK14 is required for neointimal hyperplasia by suppressing VSMC differentiation and inducing proliferation and inflammation

Injury-induced stenosis is a serious vascular complication. We previously reported that p38α (MAPK14), a redox-regulated p38MAPK family member was a negative regulator of the VSMC contractile phenotype in vitro. Here we evaluated the function of VSMC-MAPK14 in vivo in injury-induced neointima hyperplasia and the underlying mechanism using an inducible SMC-MAPK14 knockout mouse line (iSMC-MAPK14^-/-). We show that MAPK14 expression and activity were induced in VSMCs after carotid artery ligation injury in mice and ex vivo cultured human saphenous veins. While the vasculature from iSMC-MAPK14^-/- mice was indistinguishable from wildtype littermate controls at baseline, these mice exhibited reduced neointima formation following carotid artery ligation injury. Concomitantly, there was an increased VSMC contractile protein expression in the injured vessels and a decrease in proliferating cells. Blockade of MAPK14 through a selective inhibitor suppressed, while activation of MAPK14 by forced expression of an upstream MAPK14 kinase promoted VSMC proliferation in cultured VSMCs. Genome wide RNA array combined with VSMC lineage tracing studies uncovered that vascular injury evoked robust inflammatory responses including the activation of proinflammatory gene expression and accumulation of CD45 positive inflammatory cells, which were attenuated in iSMC-MAPK14^-/- mice. Using multiple pharmacological and molecular approaches to manipulate MAPK14 pathway, we further confirmed the critical role of MAPK14 in activating proinflammatory gene expression in cultured VSMCs, which occurs in a p65/NFkB-dependent pathway. Finally, we found that NOX4 contributes to MAPK14 suppression of the VSMC contractile phenotype. Our results revealed that VSMC-MAPK14 is required for injury-induced neointima formation, likely through suppressing VSMC differentiation and promoting VSMC proliferation and inflammation. Our study will provide mechanistic insights into therapeutic strategies for mitigation of vascular stenosis.

Identification of TRIM14 as a Type I IFN-Stimulated Gene Controlling Hepatitis B Virus Replication by Targeting HBx

Hepatitis B virus (HBV) remains a major cause of hepatic disease that threatens human health worldwide. Type I IFN (IFN-I) therapy is an important therapeutic option for HBV patients. The antiviral effect of IFN is mainly mediated via upregulation of the expressions of the downstream IFN-stimulated genes. However, the mechanisms by which IFN induces ISG production and inhibits HBV replication are yet to be clarified. TRIM14 was recently reported as a key molecule in the IFN-signaling pathway that regulates IFN production in response to viral infection. In this study, we sought to understand the mechanisms by which IFN restricts HBV replication. We confirmed that TRIM14 is an ISG in the hepatic cells, and that the pattern-recognition receptor ligands polyI:C and polydAdT induce TRIM14 dependent on IFN-I production. In addition, IFN-I-activated STAT1 (but not STAT3) directly bound to the TRIM14 promoter and mediated the induction of TRIM14. Interestingly, TRIM14 played an important role in IFN-I-mediated inhibition of HBV, and the TRIM14 SPRY domain interacted with the C-terminal of HBx, which might block the role of HBx in facilitating HBV replication by inhibiting the formation of the Smc-HBx–DDB1 complex. Thus, our study clearly demonstrates that TRIM14 is a STAT1-dependent ISG, and that the IFN-I–TRIM14–HBx axis shows an alternative way to understand the mechanism by which IFN-I inhibits virus replication.

Differential expression of microRNAs in recombinant Chinese hamster ovary cells treated with sodium butyrate using digital RNA counting

Sodium butyrate (NaBu) is an efficient supplement for increasing recombinant protein production in Chinese hamster ovary (CHO) cell culture. To elucidate the effects of NaBu on miRNA expression profile in recombinant CHO (rCHO) cells, differentially expressed miRNAs in NaBu-treated rCHO cells were assessed by NanoString nCounter analysis. This result showed that eight mature mouse miRNAs (let-7b, let-7d, miR-15b, miR-25, miR-27a, miR-99a, miR-125a-5p, and miR-125b-5p) were differentially expressed. Furthermore, quantitative real-time RT-PCR analysis of eight mature CHO miRNAs, annotated using a miRBase database, confirmed the transcriptomic findings. Among the potential corresponding target mRNAs for the selected mature miRNAs, seven cell growth-related target genes (e2f2, akt2, mtor, bcl-2, bim, p38α, and bmf) and five N-glycosylation-related target genes (neu1, b4galt3, gale, man1b1 and mgat4a) were selected by considering the effectiveness of NaBu on rCHO cell culture. The altered expression patterns of the 12 target mRNAs were inversely correlated with those of the selected mature miRNAs. Altogether, NanoString nCounter analysis may be useful for identifying differentially expressed miRNAs in rCHO cells.

Functional similarities of microRNAs across different types of tissue stem cells in aging

Restoration of tissue homeostasis by controlling stem cell aging is a promising therapeutic approach for geriatric disorders. The molecular mechanisms underlying age-related dysfunctions of specific types of adult tissue stem cells (TSCs) have been studied, and various microRNAs were recently reported to be involved. However, the central roles of microRNAs in stem cell aging remain unclear. Interest in this area was sparked by murine heterochronic parabiosis experiments, which demonstrated that systemic factors can restore the functions of TSCs. Age-related changes in secretion profiles, termed the senescence-associated secretory phenotype, have attracted attention, and several pro- and anti-aging factors have been identified. On the other hand, many microRNAs are linked with the age-dependent dysregulations of various physiological processes, including “stem cell aging.” This review summarizes microRNAs that appear to play common roles in stem cell aging.

Involvement of methylation of MicroRNA-122, -125b and -106b in regulation of Cyclin G1, CAT-1 and STAT3 target genes in isoniazid-induced liver injury

Background

This investigation aimed to evaluate the role of methylation in the regulation of microRNA (miR)-122, miR-125b and miR-106b gene expression and the expression of their target genes during isoniazid (INH)-induced liver injury.

Methods

Rats were given INH 50 mg kg^− 1·d^− 1 once per day for 3, 7, 10, 14, 21 and 28 days and were sacrificed. Samples of blood and liver were obtained.

Results

We analysed the methylation and expression levels of miR-122, miR-125b and miR-106b and their potential gene targets in livers. Liver tissue pathologies, histological scores and alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities changed, indicating the occurrence of liver injury. Relative expression levels of miR-122, miR-125b and miR-106b genes in the liver decreased after INH administration and correlated with the scores of liver pathology and serum AST and ALT activities, suggesting that miR-122, miR-125b and miR-106b are associated with INH-induced liver injury. The amount of methylated miR-122, miR-125b and miR-106b in the liver increased after INH administration and correlated with their expression levels, suggesting the role of methylation in regulating miRNA gene expression. Two miR-122 gene targets, cell cycle protein G1 (Cyclin G1) and cationic amino acid transporter-1 (CAT-1), also increased at the mRNA and protein levels, which suggests that lower levels of miR-122 contribute to the upregulation of Cyclin G1 and CAT-1 and might play a role in INH-induced liver injury. Signal transducer and activator of transcription 3 (STAT3) was a common target gene of miR-125b and miR-106b, and its expression levels of mRNA and protein increased after INH administration. The protein expression of phosphorylated (p)-STAT3 and the mRNA expression of RAR-related orphan receptor gamma (RORγt) regulated by p-STAT3 also increased. Meanwhile, the mRNA and protein expression of interleukin (IL)-17 regulated by RORγt, and the mRNA and protein expression of CXCL1 and MIP-2 regulated by IL-17 increased after INH administration. These results demonstrate that lower levels of hepatic miR-125b and miR-106b contribute to the upregulation of STAT3 in stimulating the secretion of inflammatory factors during INH-induced liver injury.

Conclusions

Our results suggested that DNA methylation probably regulates the expression of miRNA genes (miR-122, miR-125b, and miR-106b), affecting the expression of their gene targets (Cyclin G1, CAT-1, and STAT3) and participating in the process of INH-induced liver injury.

Electronic supplementary material

The online version of this article (10.1186/s40360-018-0201-x) contains supplementary material, which is available to authorized users.

Type III interferon-induced CBFβ inhibits HBV replication by hijacking HBx

Hepatitis B virus (HBV) and its associated chronic infection remain serious health threats worldwide. However, there is still no impactful approach for clinical treatment of hepatitis B patients. Therefore, developing a better understanding of the interactions between HBV and its host is particularly important. HBV infection has been reported to induce type-III but not type-I or type-II interferon (IFN). In this study, we identified CBFβ, an HIV enhancer, as an HBV restriction factor that is specifically induced by type-III IFN in the early stages of HBV infection. Type-III IFN-induced IL-10 played an important role in the production of CBFβ. Interestingly, the interaction between CBFβ- and HBV-encoded regulatory protein X (HBx) enhanced the stability of CBFβ, but notably blocked HBx-mediated promotion of HBV replication. CBFβ expression was lower in HBV patients than in healthy persons, and the addition of serum from HBV patients inhibited CBFβ expression in HepG2 cells. On the contrary, HBV via HBsAg inhibited type-III IFN-induced CBFβ expression and decreased the anti-HBV activity of type-III IFN, suggesting that HBV inhibits antiviral interferon-stimulated gene (ISG) expression and induces IFN resistance. Collectively, our results demonstrate that type-III IFN-triggered and IL-10-induced CBFβ are crucial factors for inhibiting HBV replication, and the HBx–CBFβ–HBsAg axis reveals a new molecular mechanism of interaction between HBV and its hosts.

Desired response to phototherapy vs photoaggravation in psoriasis: what makes the difference?

Psoriasis commonly responds beneficially to UV radiation from natural sunlight or artificial sources. Therapeutic mechanisms include the proapoptotic and immunomodulating effects of UV, affecting many cells and involving a variety of pro- and anti-inflammatory cytokines, downregulating the Th17/IL-23 response with simultaneous induction of regulatory immune cells. However, exposure to UV radiation in a subset of psoriasis patients leads to exacerbation of the disease. We herein shed light on the predisposing factors of photosensitive psoriasis, including genetics (such as HLA-Cw*0602 or CARD14), gender and coexisting photodermatoses such as polymorphic light eruption (PLE) in the context of potential molecular mechanisms behind therapeutic photoresponsiveness or photoaggravation. UV-induced damage/pathogen-associated molecular patterns, damage to self-coding RNA (signalling through Toll-like receptors), certain antimicrobial peptides and/or inflammasome activation may induce innate immunity, leading to psoriasis at the site of UV exposure when there is concomitant, predisposing resistance against UV-induced suppression of the adaptive immune response (like in PLE) that otherwise would act to reduce psoriasis.

Protective effect of pomegranate juice on retinal oxidative stress in streptozotocin-induced diabetic rats

AIM

To investigate the effect of pomegranate juice (PJ) intake on overall oxidation status in retinas of diabetic rats.

METHODS

Twenty-seven rats were divided into four groups as control (CO), diabetic (DM), control treated with PJ (CO-PJ), and diabetic treated with PJ (DM-PJ).The retina tissues were used to determine 8-hydroxy-2'-deoxyguanosine (8OHdG), malondialdehyde (MDA), reduced glutathione (GSH) levels, and the enzyme activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px).

RESULTS

The levels of 8OHdG and MDA were significantly increased in the retina of DM group compared to CO group (P=0.001, P<0.001 respectively). Both 8OHdG and MDA levels were decreased in PJ-DM group compared to DM group (P=0.004, P<0.001 respectively). The activities of antioxidant enzymes GSH, SOD, and GDH-Px were significantly decreased in the retina of DM group compared to CO group (P≤0.01). GSH and GSH-Px activities were higher in PJ-DM group compared with DM group (P=0.010, P=0.042, respectively) but SOD activity was not statistically different (P=0.938).

CONCLUSION

PJ intake is found to be effective in decreasing oxidative end products, and in increasing the activities of antioxidant enzymes in diabetic retinas of rats, which suggests it may be effective against oxidative stress in diabetic retinas.

Age-Associated Decrease of the Histone Methyltransferase SUV39H1 in HSC Perturbs Heterochromatin and B Lymphoid Differentiation

The capacity of hematopoietic stem cells (HSC) to generate B lymphocytes declines with age, contributing to impaired immune function in the elderly. Here we show that the histone methyltransferase SUV39H1 plays an important role in human B lymphoid differentiation and that expression of SUV39H1 decreases with age in both human and mouse HSC, leading to a global reduction in H3K9 trimethylation and perturbed heterochromatin function. Further, we demonstrate that SUV39H1 is a target of microRNA miR-125b, a known regulator of HSC function, and that expression of miR-125b increases with age in human HSC. Overexpression of miR-125b and inhibition of SUV39H1 in young HSC induced loss of B cell potential. Conversely, both inhibition of miR-125 and enforced expression of SUV39H1 improved the capacity of HSC from elderly individuals to generate B cells. Our findings highlight the importance of heterochromatin regulation in HSC aging and B lymphopoiesis.

MTDH promotes glioma invasion through regulating miR-130b-ceRNAs

Cell invasion is crucial for high mortality and recurrence rate in glioma. Epithelial-mesenchymal transition (EMT) is an important step in cancer invasion. Metadherin (MTDH) contributes to EMT in several cancers, but the role and mechanism of MTDH in EMT-like process of glioma remain unknown. Here we demonstrate that MTDH was overexpressed in glioma tissues and cells and induced EMT-like change and invasion of glioma cells. Interestingly, MTDH could modulate the expression of a group of glioma-related miRNAs. In particular, MTDH upregulated miR-130b transcription via acting as a coactivator of NF-kB. MiR-130b promoted EMT-like change and invasion of glioma cells through targeting multiple EMT-related genes, including PTEN, PPP2CA and SMAD7. In addition, PTEN acted as the competing endogenous RNA (ceRNA) to affect PPP2CA and SMAD7 expression, and inhibited EMT-like change in glioma cells. Furthermore, miR-130b mediated EMT-like change induced by MTDH, and MTDH inhibited the expression levels of PTEN, PPP2CA and SMAD7. Taken together, we reveal a novel mechanism that MTDH induces EMT-like change and invasion of glioma via the regulation of miR-130b-ceRNAs, providing the first direct link between MTDH and miRNAs in cancer cells.

miR-125b predicts childhood acute lymphoblastic leukaemia poor response to BFM chemotherapy treatment

BACKGROUND

Despite the favourable survival rates of childhood acute lymphoblastic leukaemia (ALL), a significant number of patients present resistance to antileukaemic agents and dismal prognosis. In this study, we analysed miR-125b expression in childhood ALL and evaluated its clinical utility for patients treated with Berlin-Frankfurt-Münster (BFM) protocol.

METHODS

The study included 272 bone marrow specimens obtained on diagnosis and on BFM day 33 from 125 patients and 64 healthy children. Following extraction, RNA was polyadenylated and reverse transcribed. miR-125b levels were quantified by quantitative PCR. Cytogenetics, immunohistotype and MRD were analysed according to international guidelines.

RESULTS

Downregulated miR-125b levels were detected in childhood ALL patients and correlated with adverse prognosis. Following BFM induction, miR-125b levels were significantly increased, however, elevated day 33/diagnosis miR-125b ratio was associated with unfavourable disease features. Loss of miR-125b during diagnosis and higher day 33/diagnosis ratio were correlated with stronger risk for disease short-term relapse and patients' worse survival. Moreover, multivariate regression models highlighted the independent prognostic value of miR-125b for childhood ALL. Finally, the combination of miR-125b with clinically used disease markers clearly enhanced the prediction of patients' resistance to BFM chemotherapy.

CONCLUSIONS

miR-125b significantly improves the prognosis of childhood ALL patients' outcome under BFM treatment.

Altered miRNA expression in aniline-mediated cell cycle progression in rat spleen

Aniline exposure is associated with toxicity to the spleen, however, early molecular events in aniline-induced cell cycle progression in the spleen remain unknown. MicroRNAs (miRNAs) have been implicated in tumor development by modulating key cell cycle regulators and controlling cell proliferation. This study was, therefore, undertaken on the expression of miRNAs, regulation of cyclins and cyclin-dependent kinases (CDKs) in an experimental condition that precedes a tumorigenic response. Male SD rats were treated with aniline (1 mmol/kg/day by gavage) for 7 days, and expression of miRNAs, cyclins and CDKs in rat spleens were analyzed. Microarray and/or qPCR analyses showed that aniline exposure led to significantly decreased miRNA expression of let-7a, miR-24, miR-34c, miR-100, miR-125b, and greatly increased miR-181a. The aberrant expression of miRNAs was associated with significantly increased protein expression of cyclins A, B1, D3 and E. Furthermore, remarkably enhanced expression of CDKs like CDK1, CDK2, CDK4, CDK6, especially p-CDK1 and p-CDK2 as well as alternations in the expression of pRB, p27, and CDC25A in the spleens of aniline-treated rats was also observed. The data suggest that aniline exposure leads to aberrant expression of miRNAs in the spleen which could be important in the regulation of cell cycle proteins. Our findings, thus, provide new insight into the role of miRNAs in cell cycle progression, which may contribute to aniline-induced tumorigenic response in the spleen.

MicroRNA-125a and -b inhibit A20 and MAVS to promote inflammation and impair antiviral response in COPD

Influenza A virus (IAV) infections lead to severe inflammation in the airways. Patients with chronic obstructive pulmonary disease (COPD) characteristically have exaggerated airway inflammation and are more susceptible to infections with severe symptoms and increased mortality. The mechanisms that control inflammation during IAV infection and the mechanisms of immune dysregulation in COPD are unclear. We found that IAV infections lead to increased inflammatory and antiviral responses in primary bronchial epithelial cells (pBECs) from healthy nonsmoking and smoking subjects. In pBECs from COPD patients, infections resulted in exaggerated inflammatory but deficient antiviral responses. A20 is an important negative regulator of NF-κB-mediated inflammatory but not antiviral responses, and A20 expression was reduced in COPD. IAV infection increased the expression of miR-125a or -b, which directly reduced the expression of A20 and mitochondrial antiviral signaling (MAVS), and caused exaggerated inflammation and impaired antiviral responses. These events were replicated in vivo in a mouse model of experimental COPD. Thus, miR-125a or -b and A20 may be targeted therapeutically to inhibit excessive inflammatory responses and enhance antiviral immunity in IAV infections and in COPD.

Type I IFN augments IL-27-dependent TRIM25 expression to inhibit HBV replication

Hepatitis B virus (HBV) can cause chronic hepatitis B, which may lead to cirrhosis and liver cancer. Type I interferon (IFN) is an approved drug for the treatment of chronic hepatitis B. However, the fundamental mechanisms of antiviral action by type I IFN and the downstream signaling pathway are unclear. TRIM25 is an IFN-stimulated gene (ISG) that has an important role in RIG-I ubiquitination and activation. Whether TRIM25 is induced in liver cells by type I IFN to mediate anti-HBV function remains unclear. Here we report that interleukin-27 (IL-27) has a critical role in IFN-induced TRIM25 upregulation. TRIM25 induction requires both STAT1 and STAT3. In TRIM25 knockout HepG2 cells, type I IFN production was consistently attenuated and HBV replication was increased, whereas overexpression of TRIM25 in HepG2 cells resulted in elevated IFN production and reduced HBV replication. More interestingly, we found that TRIM25 expression was downregulated in HBV patients and the addition of serum samples from HBV patients could inhibit TRIM25 expression in HepG2 cells, suggesting that HBV might have involved a mechanism to inhibit antiviral ISG expression and induce IFN resistance. Collectively, our results demonstrate that type I IFN -induced TRIM25 is an important factor in inhibiting HBV replication, and the IFN-IL-27-TRIM25 axis may represent a new target for treating HBV infection.

cel-mir-237 and its homologue, hsa-miR-125b, modulate the cellular response to ionizing radiation

Elucidating the mechanisms involved in sensitizing radioresistant tumors to ionizing radiation (IR) treatments while minimizing injury to surrounding normal tissue is an important clinical goal. Due to their sequence-derived specificity and properties as gene regulators in IR-affected pathways, microRNAs (miRNAs) could serve as adjuvant therapeutic agents that alter cellular sensitivity to radiation treatment. To identify radiosensitizing miRNAs, we initially utilized the Caenorhabditis elegans vulval cell model, an in vivo system developed to study IR-dependent radiosensitivity as a measure of clonogenic cell death. We tested several candidate miRNA-deletion mutants post γ-irradiation and identified cel-mir-237 as a miRNA which when deleted caused animals to be more resistant to IR, whereas cel-mir-237 overexpressing strains were IR sensitive. In addition, wild-type animals downregulated cel-mir-237 levels post IR in a time-dependent manner. We identified jun-1 (JUN transcription factor homolog) as a novel target of cel-mir-237. Specifically, jun-1 transcript levels increased in wild-type animals post γ-irradiation, and loss of cel-mir-237 also resulted in higher jun-1 expression. As expected, loss of jun-1 resulted in IR sensitivity, similar to the phenotype of cel-mir-237 overexpressors. As miR-237 is the homolog of human miR-125, we validated our findings in MCF-7 and MDA-MB-231 breast cancer cell lines, which harbor lower hsa-miR-125b levels than normal human mammary epithelial cells (HMECs). Forced expression of hsa-miR-125b in these cells resulted in radiosensitivity, as seen by reduced clonogenic survival, enhanced apoptotic activity and enhanced senescence post IR. Finally, re-expression of c-JUN in MDA-MB-231 cells promoted radioresistance and abrogated miR-125-mediated radiosensitization. Our findings suggest that overexpression of cel-mir-237 and its homolog, hsa-miR-125b, functions as sensitizers to γ-irradiation in both a nematode in vivo model and breast cancer cells, and could potentially be utilized as an adjuvant therapeutic to enhance radiation sensitivity.

Hsa-miR-520d-5p promotes survival in human dermal fibroblasts exposed to a lethal dose of UV irradiation

We previously reported that hsa-miR-520d-5p is functionally involved in the induction of the epithelial–mesenchymal transition and stemness-mediated processes in normal cells and cancer cells, respectively. On the basis of the synergistic effect of p53 upregulation and demethylation induced by 520d-5p, the current study investigated the effect of this miRNA on apoptotic induction by ultraviolet B (UVB) light in normal human dermal fibroblast (NHDF) cells. 520d-5p was lentivirally transfected into NHDF cells either before or after a lethal dose of UVB irradiation (302 nm) to assess its preventive or therapeutic effects, respectively. The methylation level, gene expression, production of type I collagen and cell cycle distribution were estimated in UV-irradiated cells. NHDF cells transfected with 520d-5p prior to UVB irradiation had apoptotic characteristics, and the transfection exerted no preventive effects. However, transfection with 520d-5p into NHDF cells after UVB exposure resulted in the induction of reprogramming in damaged fibroblasts, the survival of CD105-positive cells, an extended cell lifespan and prevention of cellular damage or malfunction; these outcomes were similar to the effects observed in 520d-5p-transfected NHDF cells (520d/NHDF). The gene expression of c-Abl (Abelson murine leukemia viral oncogene homolog 1), ATR (ataxia telangiectasia and Rad3-related protein), and BRCA1 (breast cancer susceptibility gene I) in transfectants was transcriptionally upregulated in order. These mechanistic findings indicate that ATR-dependent DNA damage repair was activated under this stressor. In conclusion, 520d-5p exerted a therapeutic effect on cells damaged by UVB and restored them to a normal senescent state following functional restoration via survival of CD105-positive cells through c-Abl-ATR-BRCA1 pathway activation, p53 upregulation, and demethylation.

MicroRNA-125b as a new potential biomarker on diagnosis of renal ischemia-reperfusion injury

BACKGROUND

Acute renal failure is commonly seen in the perioperative period. Ischemia-reperfusion (IR) injury plays a major role in acute renal failure and delayed graft function. MicroRNAs (miRs), which are pivotal modulators of cell activities, offer a major opportunity for affective diagnosis and treatment strategies because they are tissue specific and in the center of gene expression modulation. The effect of bardoxolone methyl (BM) on miR-21, miR-223-5p, and miR-125b in renal IR injury was evaluated in this study.

METHODS

Wistar-Albino rats (12-16 wk old, weighing 300-350 g) were used in the study. Rats (n = 6) were randomized into three groups (control, IR, and BM + IR). Tissue levels of miRs were analyzed with reverse transcription polymerase chain reaction.

RESULTS

Significant reduction of urea and total oxidant status, increase of total antioxidant status, and oxidative stress index were identified in the IR + BM group compared with the IR group. Significant increases of miR-21 (2842.82-fold) and miR-125b (536.8-fold) were identified in the IR group compared with the control group; however, miR-223-5p levels did not show any significant difference. Also, miR-21 and miR-125b were significantly reduced in the IR + BM group compared with the IR group. Reduced histopathologic changes were observed in the IR + BM group. A significant decrease in the number of tunel-positive cells was identified in the IR + BM group compared with the IR group.

CONCLUSIONS

miR-125b was significantly increased in IR injury; thus, miR-125b can be a potential novel marker that can be used in diagnosis and treatment of renal IR injury. BM reduces miR-21 and miR-125b in case of IR injury and makes functional and histopathologic repairs.

HBsAg blocks TYPE I IFN induced up-regulation of A3G through inhibition of STAT3

Interferon (IFN) is a regularly utilized therapeutic for the treatment of chronic hepatitis B and appears to induce superior HBeAg seroconversion comparing nucleos/tide analogs. However, the mechanisms underlying IFN inhibition of HBV replication, as well as poor responses to IFN are unclear. Apobec3G has been reported to be involved in regulating HBV replication. In this study, we investigated Apobec3G expression and regulatory pathways during HBV infection. We show that over-expression of A3G leads to inhibition of HBV replication. We also show that IFN induces a significant increase in A3G protein expression, which is associated with STAT3 activation. We further show that A3G expression in HBV patients is lower compared to non-infected controls, possibly by HBsAg which inhibits IFN induced A3G up-regulation in a dose dependent manner. This process is likely mediated through inhibition of STAT3-Ser727 phosphorylation. The results presented in this study indicate that STAT3 plays an important role in IFN-induced A3G production, and HBsAg may correlated with poor response to IFN treatment.

PARN deadenylase is involved in miRNA-dependent degradation of TP53 mRNA in mammalian cells

mRNA deadenylation is under the control of cis-acting regulatory elements, which include AU-rich elements (AREs) and microRNA (miRNA) targeting sites, within the 3' untranslated region (3' UTRs) of eukaryotic mRNAs. Deadenylases promote miRNA-induced mRNA decay through their interaction with miRNA-induced silencing complex (miRISC). However, the role of poly(A) specific ribonuclease (PARN) deadenylase in miRNA-dependent mRNA degradation has not been elucidated. Here, we present evidence that not only ARE- but also miRNA-mediated pathways are involved in PARN-mediated regulation of the steady state levels of TP53 mRNA, which encodes the tumor suppressor p53. Supporting this, Argonaute-2 (Ago-2), the core component of miRISC, can coexist in complexes with PARN resulting in the activation of its deadenylase activity. PARN regulates TP53 mRNA stability through not only an ARE but also an adjacent miR-504/miR-125b-targeting site in the 3' UTR. More importantly, we found that miR-125b-loaded miRISC contributes to the specific recruitment of PARN to TP53 mRNA, and that can be reverted by the ARE-binding protein HuR. Together, our studies provide new insights into the role of PARN in miRNA-dependent control of mRNA decay and into the mechanisms behind the regulation of p53 expression.

[Advances of lentiviral vectors]

Lentiviral vectors are currently very effective tools in molecular and cell experiment. Lentiviral vector, a kind of retroviral vectors, has a number of unique advantages in target gene transferation, for example, the ability of transfection to the dividing or nondividing cells, its high efficiency of transfection and a capacity of large target gene fragments. This paper describes the sources of lentiviral vectors, molecular characteristics, research progress, etc.

Induction of miRNA-181a by genotoxic treatments promotes chemotherapeutic resistance and metastasis in breast cancer

Acquired therapeutic resistance is the major drawback to effective systemic therapies for cancers. Aggressive triple-negative breast cancers (TNBC) develop resistance to chemotherapies rapidly, whereas the underlying mechanisms are not completely understood. Here we show that genotoxic treatments significantly increased the expression of miR-181a in TNBC cells, which enhanced TNBC cell survival and metastasis upon Doxorubicin treatment. Consistently, high miR-181a level associated with poor disease free survival and overall survival after treatments in breast cancer patients. The upregulation of miR-181a was orchestrated by transcription factor STAT3 whose activation depended on NF-κB-mediated IL-6 induction in TNBC cells upon genotoxic treatment. Intriguingly, activated STAT3 not only directly bound to MIR181A1 promoter to drive transcription but also facilitated the recruitment of MSK1 to the same region where MSK1 promoted a local active chromatin state by phosphorylating histone H3. We further identified BAX as a direct functional target of miR-181a, whose suppression decreased apoptosis and increased invasion of TNBC cells upon Dox treatment. These results were further confirmed by evidence that suppression of miR-181a significantly enhanced therapeutic response and reduced lung metastasis in a TNBC orthotopic model. Collectively, our data suggested that miR-181a induction had a critical role in promoting therapeutic resistance and aggressive behavior of TNBC cells upon genotoxic treatment. Antagonizing miR-181a may serve as a promising strategy to sensitize TNBC cells to chemotherapy and mitigate metastasis.

A New Paradigm to Mitigate Osteosarcoma by Regulation of MicroRNAs and Suppression of the NF-κB Signaling Cascade

Osteosarcoma (OS) is one of the most common malignant primary bone tumors and NF-κB appears to play a causative role, but the mechanisms are poorly understood. OS is one of the pleomorphic, highly metastasized and invasive neoplasm which is capable to generate osteoid, osteoclast and osteoblast matrix. Its high incidence has been reported in adolescent and children. Cell signal cascade is the pivotal functional mechanism acquired during the differentiation, proliferation, growth and survival of the cells in neoplasm including OS. The major limitation to the success of chemotherapy in OS is the development of multidrug resistance (MDR). Answers to all such queries might come from the knock-in experiments in which the combined approach of miRNAs with NF-κB pathway is put into use. Abnormal miRNAs can modulate several epigenetical switching as a hallmark of number of diseases via different cell signaling. Studies on miRNAs have opened up the new avenues for both the diagnosis and treatment of cancers including OS. Collectively, through the present study an attempt has been made to establish a new systematic approach for the investigation of microRNAs, biophysiological factors and their target pairs with NF-κB to ameliorate oncogenesis with the “bridge between miRNAs and NF-κB”. The application of NF-κB inhibitors in combination with miRNAs is expected to result in a more efficient killing of the cancer stem cells and a slower or less likely recurrence of cancer.

Psoralen derivatives as inhibitors of NF-κB interaction: the critical role of the furan ring

Simplified analogues of previously reported NF-κB interaction inhibitors, lacking the furan moiety, were synthesized and evaluated by performing experiments based on electrophoretic mobility shift assay (EMSA). The synthetic modifications led to simpler coumarin derivatives with lower activity allowing to better understand the minimal structural requirement for the binding to NF-κB.

TRAF Family Member-associated NF-κB Activator (TANK) Inhibits Genotoxic Nuclear Factor κB Activation by Facilitating Deubiquitinase USP10-dependent Deubiquitination of TRAF6 Ligase

DNA damage-induced NF-κB activation plays a critical role in regulating cellular response to genotoxic stress. However, the molecular mechanisms controlling the magnitude and duration of this genotoxic NF-κB signaling cascade are poorly understood. We recently demonstrated that genotoxic NF-κB activation is regulated by reversible ubiquitination of several essential mediators involved in this signaling pathway. Here we show that TRAF family member-associated NF-κB activator (TANK) negatively regulates NF-κB activation by DNA damage via inhibiting ubiquitination of TRAF6. Despite the lack of a deubiquitination enzyme domain, TANK has been shown to negatively regulate the ubiquitination of TRAF proteins. We found TANK formed a complex with MCPIP1 (also known as ZC3H12A) and a deubiquitinase, USP10, which was essential for the USP10-dependent deubiquitination of TRAF6 and the resolution of genotoxic NF-κB activation upon DNA damage. Clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9-mediated deletion of TANK in human cells significantly enhanced NF-κB activation by genotoxic treatment, resulting in enhanced cell survival and increased inflammatory cytokine production. Furthermore, we found that the TANK-MCPIP1-USP10 complex also decreased TRAF6 ubiquitination in cells treated with IL-1β or LPS. In accordance, depletion of USP10 enhanced NF-κB activation induced by IL-1β or LPS. Collectively, our data demonstrate that TANK serves as an important negative regulator of NF-κB signaling cascades induced by genotoxic stress and IL-1R/Toll-like receptor stimulation in a manner dependent on MCPIP1/USP10-mediated TRAF6 deubiquitination.

MicroRNA-125b modulates inflammatory chemokine CCL4 expression in immune cells and its reduction causes CCL4 increase with age

Chemokines play a pivotal role in regulating the immune response through a tightly controlled expression. Elevated levels of inflammatory chemokines commonly occur with aging but the mechanism underlying this age-associated change is not fully understood. Here, we report the role of microRNA-125b (miR-125b) in regulating inflammatory CC chemokine 4 (CCL4) expression in human immune cells and its altered expression with aging. We first analyzed the mRNA level of CCL4 in eight different types of immune cells including CD4 and CD8 T-cell subsets (naïve, central and effector memory), B cells and monocytes in blood from both young (≤42 years) and old (≥70 years) adults. We observed that monocytes and naïve CD8 T cells expressed higher levels of CCL4 and exhibited an age-related increase in CCL4. We then found the level of miR-125b was inversely correlated with the level of CCL4 in these cells, and the level of miR-125b was reduced in monocytes and naïve CD8 T cells of the old compared to the young adults. Knock-down of miR-125b by shRNA in monocytes and naïve CD8 T cells led to an increase of CCL4 protein, whereas enhanced miR-125b expression by transfection in naïve CD8 T cells resulted in a reduction of the CCL4 mRNA and protein in response to stimulation. Finally, we demonstrated that miR-125b action requires the 'seed' sequence in 3'UTR of CCL4. Together these findings demonstrated that miR-125b is a negative regulator of CCL4 and its reduction is partially responsible for the age-related increase of CCL4.

Human mesenchymal stromal cell lysates as a novel strategy to recover liver function

AIM

It is unknown if the beneficial effects of mesenchymal stromal cells (MSC) transplantation into the liver are dependent on their anchorage and differentiation into hepatocytes or rather the result of the release of stem cell intracellular content with hepatoprotector properties.

MATERIALS & METHODS

The effects of intact MSC transplantation were compared with the infusion of MSC lysates in an experimental rat model of acute liver failure.

RESULTS

A more powerful hepatoprotective and antiapoptotic effect was obtained after infusion of MSC lysates than intact MSC. Changes in IL-6 levels and miRNAs might explain the beneficial effects of MSC lysates.

CONCLUSION

Infusion of MSC lysates show a better hepatoprotective effect than the transplantation of intact MSC.

A New Paradigm to Mitigate Osteosarcoma by Regulation of MicroRNAs and Suppression of the NF-κB Signaling Cascade

Osteosarcoma (OS) is one of the most common malignant primary bone tumors and NF-κB appears to play a causative role, but the mechanisms are poorly understood. OS is one of the pleomorphic, highly metastasized and invasive neoplasm which is capable to generate osteoid, osteoclast and osteoblast matrix. Its high incidence has been reported in adolescent and childevrepen. Cell signal cascade is the pivotal functional mechanism acquired during the differentiation, proliferation, growth and survival of the cells in neoplasm including OS. The major limitation to the success of chemotherapy in OS is the development of multidevrepug resistance (Mdevrep). Answers to all such queries might come from the knock-in experiments in which the combined approach of miRNAs with NF-κB pathway is put into use. Abnormal miRNAs can modulate several epigenetical switching as a hallmark of number of diseases via different cell signaling. Studies on miRNAs have opened up the new avenues for both the diagnosis and treatment of cancers including OS. Collectively, through the present study an attempt has been made to establish a new systematic approach for the investigation of microRNAs, biophysiological factors and their target pairs with NF-κB to ameliorate oncogenesis with the "bridge between miRNAs and NF-κB". The application of NF-κB inhibitors in combination with miRNAs is expected to result in a more efficient killing of the cancer stem cells and a slower or less likely recurrence of cancer.

Decreased microRNA-125a-3p contributes to upregulation of p38 MAPK in rat trigeminal ganglions with orofacial inflammatory pain

Orofacial inflammatory pain is a difficult clinical problem, and the specific molecular mechanisms for this pain remain largely unexplained. The present study aimed to determine the differential expression of microRNAs (miRNAs) and disclose the underlying role of miR-125a-3p in orofacial inflammatory pain induced by complete Freund's adjuvant (CFA). Thirty-two differentially expressed miRNAs were first screened using a microarray chip in ipsilateral trigeminal ganglions (TGs) following CFA injection into the orofacial skin innervated by trigeminal nerve, and a portion of them, including miR-23a*, -24-2*, -26a, -92a, -125a-3p, -183 and -299 were subsequently selected and validated by qPCR. The target genes were predicted based on the miRWalk website and were further analyzed by gene ontology (GO). Further studies revealed miR-125a-3p expression was down-regulated, whereas both the expression of p38 MAPK (mitogen-activated protein kinase) alpha and CGRP (calcitonin gene-related peptide) were up-regulated in ipsilateral TGs at different time points after CFA injection compared with control. Furthermore, mechanistic study revealed that miR-125a-3p negatively regulates p38 alpha gene expression and is positively correlated with the head withdrawal threshold reflecting pain. Luciferase assay showed that binding of miR-125a-3p to the 3′UTR of p38 alpha gene suppressed the transcriptional activity, and overexpression of miR-125a-3p significantly inhibited the p38 alpha mRNA level in ND8/34 cells. Taken together, our results show that miR-125a-3p is negatively correlated with the development and maintenance of orofacial inflammatory pain via regulating p38 MAPK.

NRF2-driven miR-125B1 and miR-29B1 transcriptional regulation controls a novel anti-apoptotic miRNA regulatory network for AML survival

Transcription factor NRF2 is an important regulator of oxidative stress. It is involved in cancer progression, and has abnormal constitutive expression in acute myeloid leukaemia (AML). Posttranscriptional regulation by microRNAs (miRNAs) can affect the malignant phenotype of AML cells. In this study, we identified and characterised NRF2-regulated miRNAs in AML. An miRNA array identified miRNA expression level changes in response to NRF2 knockdown in AML cells. Further analysis of miRNAs concomitantly regulated by knockdown of the NRF2 inhibitor KEAP1 revealed the major candidate NRF2-mediated miRNAs in AML. We identified miR-125B to be upregulated and miR-29B to be downregulated by NRF2 in AML. Subsequent bioinformatic analysis identified putative NRF2 binding sites upstream of the miR-125B1 coding region and downstream of the mir-29B1 coding region. Chromatin immunoprecipitation analyses showed that NRF2 binds to these antioxidant response elements (AREs) located in the 5' untranslated regions of miR-125B and miR-29B. Finally, primary AML samples transfected with anti-miR-125B antagomiR or miR-29B mimic showed increased cell death responsiveness either alone or co-treated with standard AML chemotherapy. In summary, we find that NRF2 regulation of miR-125B and miR-29B acts to promote leukaemic cell survival, and their manipulation enhances AML responsiveness towards cytotoxic chemotherapeutics.

Identification of ultraviolet B radiation‑induced microRNAs in normal human dermal papilla cells

Ultraviolet (UV) radiation impairs intracellular functions by directly damaging DNA and by indirectly generating reactive oxygen species (ROS), which induce cell cycle arrest and apoptosis. UV radiation can also alter gene expression profiles, including those of mRNA and microRNA (miRNA). The effects of UV radiation on cellular functions and gene expression have been widely documented in human skin cells such as keratinocytes, melanocytes and dermal fibroblasts, but the effect it has on other types of skin cell such as dermal papilla cells, which are crucial in the induction of hair follicle growth, remains unknown. In the current study, the effect of UV radiation on physiological changes and miRNA-based expression profiles in normal human dermal papilla cells (nHDPs) was investigated. UVB radiation of ≥50 mJ/cm² displayed high cytotoxicity and apoptosis in a dose-dependent manner. In addition, ROS generation was exhibited in UVB-irradiated nHDPs. Furthermore, using miRNA microarray analysis, it was demonstrated that the expression profiles of 42 miRNAs in UVB-irradiated nHDPs were significantly altered compared with those in the controls (35 upregulated and 7 downregulated). The biological functions of the differentially expressed miRNAs were studied with gene ontology analysis to identify their putative target mRNAs, and were demonstrated to be involved in cell survival- and death-related functions. Overall, the results of the present study provide evidence that miRNA-based cellular mechanisms may be involved in the UVB-induced cellular response in nHDPs.

MicroRNAs: novel players in cancer diagnosis and therapies

First discovered in 1993, microRNAs (miRNAs) have been one of the hottest research areas over the past two decades. Oftentimes, miRNAs levels are found to be dysregulated in cancer patients. The potential use of miRNAs in cancer therapies is an emerging and promising field, with research finding miRNAs to play a role in cancer initiation, tumor growth, and metastasis. Therefore, miRNAs could become an integral part from cancer diagnosis to treatment in future. This review aims to examine current novel research work on the potential roles of miRNAs in cancer therapies, while also discussing several current challenges and needed future research.

Chlamydia muridarum infection associated host MicroRNAs in the murine genital tract and contribution to generation of host immune response

PROBLEM

Chlamydia trachomatis (CT) is the leading sexually transmitted bacterial infection in humans and is associated with reproductive tract damage. However, little is known about the involvement and regulation of microRNAs (miRs) in genital CT.

METHODS

We analyzed miRs in the genital tract (GT) following C. muridarum (murine strain of CT) challenge of wild type (WT) and CD4(+) T-cell deficient (CD4(-/-)) C57BL/6 mice at days 6 and 12 post-challenge.

RESULTS

At day 6, miRs significantly downregulated in the lower GT were miR-125b-5p, -16, -214, -23b, -135a, -182, -183, -30c, and -30e while -146 and -451 were significantly upregulated, profiles not exhibited at day 12 post-bacterial challenge. Significant differences in miR-125b-5p (+5.06-fold change), -135a (+4.9), -183 (+7.9), and -182 (+3.2) were observed in C. muridarum-infected CD4(-/-) compared to WT mice. In silico prediction and mass spectrometry revealed regulation of miR-135a and -182 and associated proteins, that is, heat-shock protein B1 and alpha-2HS-glycoprotein.

CONCLUSION

This study provides evidence on regulation of miRs following genital chlamydial infection suggesting a role in pathogenesis and host immunity.

microRNA expression and biogenesis in cellular response to ionizing radiation

Increasing evidence demonstrates that the expression levels of microRNAs (miRNAs) significantly change upon ionizing radiation (IR) and play a critical role in cellular response to IR. Although several radiation responsive miRNAs and their targets have been identified, little is known about how miRNAs expression and biogenesis is regulated by IR-caused DNA damage response (DDR). Hence, in this review, we summarize miRNA expression and biogenesis in cellular response to IR and mainly elucidate the regulatory mechanisms of miRNA expression and biogenesis from different aspects including ataxia-telangiectasia mutated (ATM) kinase, p53/p63/p73 family and other potential factors. Furthermore, we focus on ΔNp73, which might be a potential regulator of miRNA expression and biogenesis in cellular response to IR. miRNAs could effectively activate the IR-induced DDR and modulate the radiation response and cellular radiosensitivity, which have an important potential clinical application. Therefore, thoroughly understanding the regulatory mechanisms of miRNAs expression and biogenesis in radiation response will provide new insights for clinical cancer radiotherapy.