Large-scale validation of skin prion seeding activity as a biomarker for diagnosis of prion diseases.

Definitive diagnosis of sporadic Creutzfeldt-Jakob disease (sCJD) relies on the examination of brain tissues for the pathological prion protein (PrPSc). Our previous study revealed that PrPSc-seeding activity (PrPSc-SA) is detectable in skin of sCJD patients by an ultrasensitive PrPSc seed amplification assay (PrPSc-SAA) known as real-time quaking-induced conversion (RT-QuIC). A total of 875 skin samples were collected from 2 cohorts (1 and 2) at autopsy from 2-3 body areas of 339 cases with neuropathologically confirmed prion diseases and non-sCJD controls. The skin samples were analyzed for PrPSc-SA by RT-QuIC assay. The results were compared with demographic information, clinical manifestations, cerebrospinal fluid (CSF) PrPSc-SA, other laboratory tests, subtypes of prion diseases defined by the methionine (M) or valine (V) polymorphism at residue 129 of PrP, PrPSc types (#1 or #2), and gene mutations in deceased patients. RT-QuIC assays of the cohort #1 by two independent laboratories gave 87.3% or 91.3% sensitivity and 94.7% or 100% specificity, respectively. The cohort #2 showed sensitivity of 89.4% and specificity of 95.5%. RT-QuIC of CSF available from 212 cases gave 89.7% sensitivity and 94.1% specificity. The sensitivity of skin RT-QuIC was subtype dependent, being highest in sCJDVV1-2 subtype, followed by VV2, MV1-2, MV1, MV2, MM1, MM1-2, MM2, and VV1. The skin area next to the ear gave highest sensitivity, followed by lower back and apex of the head. Although no difference in brain PrPSc-SA was detected between the cases with false negative and true positive skin RT-QuIC results, the disease duration was significantly longer with the false negatives [12.0 ± 13.3 (months, SD) vs. 6.5 ± 6.4, p < 0.001]. Our study validates skin PrPSc-SA as a biomarker for the detection of prion diseases, which is influenced by the PrPSc types, PRNP 129 polymorphisms, dermatome sampled, and disease duration.

Multinomial classification of NLRP3 inhibitory compounds based on large scale machine learning approaches.

The role of NLRP3 inflammasome in innate immunity is newly recognized. The NLRP3 protein is a family of nucleotide-binding and oligomerization domain-like receptors as well as a pyrin domain-containing protein. It has been shown that NLRP3 may contribute to the development and progression of a variety of diseases, such as multiple sclerosis, metabolic disorders, inflammatory bowel disease, and other auto-immune and auto-inflammatory conditions. The use of machine learning methods in pharmaceutical research has been widespread for several decades. An important objective of this study is to apply machine learning approaches for the multinomial classification of NLRP3 inhibitors. However, data imbalances can affect machine learning. Therefore, a synthetic minority oversampling technique (SMOTE) has been developed to increase the sensitivity of classifiers to minority groups. The QSAR modelling was performed using 154 molecules retrieved from the ChEMBL database (version 29). The accuracy of the multiclass classification top six models was found to fall within ranges of 0.99 to 0.86, and log loss ranges of 0.2 to 2.3, respectively. The results showed that the receiver operating characteristic curve (ROC) plot values significantly improved when tuning parameters were adjusted and imbalanced data was handled. Moreover, the results demonstrated that SMOTE offers a significant advantage in handling imbalanced datasets as well as substantial improvements in overall accuracy of machine learning models. The top models were then used to predict data from unseen datasets. In summary, these QSAR classification models exhibited robust statistical results and were interpretable, which strongly supported their use for rapid screening of NLRP3 inhibitors.

Insight into TLR4 receptor inhibitory activity via QSAR for the treatment of Mycoplasma pneumonia disease.

Mycoplasma pneumoniae (MP) is one of the most common pathogenic organisms causing upper and lower respiratory tract infections, lung injury, and even death in young children. Toll-like receptors (TLRs) play an important role in innate immunity by allowing the host to recognize pathogens invading the body. Previous studies demonstrated that TLR4 is a potential therapeutic target for the treatment of MP pneumonia. Therefore, the present study aimed to screen biologically active ingredients that target the TLR4 receptor pathway. We first used molecular docking to screen out the active compounds inhibiting the TLR4 pathway, and then used regression and classification machine learning algorithms to establish a quantitative structure-activity relationship (QSAR) model to predict the biological activity of the screened compounds. A total of 78 molecules were used in QSAR modelling, which were retrieved from the ChEMBL database. The QSAR models had acceptable correlation coefficients of R 2 on the training and testing dataset in the range of 0.96 to 0.91 and 0.93 to 0.76, respectively. The multiclass classification models showed accuracy on training and testing data within ranges of 1.0 to 0.70, 0.96 to 0.63, and log loss ranges from 0.27 to 8.63, respectively. In addition, molecular descriptors and fingerprints have been studied as structural elements involved in increased and decreased inhibitory activities. These results provide a quantitative analysis of QSAR and classification models applicable for high-throughput screening, as well as insights into the mechanisms of inhibition of TLR4 antagonists.

Ochratoxin A-induced genotoxic and epigenetic mechanisms lead to Alzheimer disease: its modulation with strategies.

Ochratoxin A (OTA) is a naturally occurring mycotoxin mostly found in food items including grains and coffee beans. It induces DNA single-strand breaks and has been considered to be carcinogenic. It is recognized as a serious threat to reproductive health both in males and females. OTA is highly nephrotoxic and carcinogenic, and its potency changes evidently between species and sexes. There is a close association between OTA, mutagenicity, carcinogenicity, and genotoxicity, but the underlying mechanisms are not clear. Reports regarding genotoxic effects in relation to OTA which leads to the induction of DNA adduct formation, protein synthesis inhibition, perturbation of cellular energy production, initiation of oxidative stress, induction of apoptosis, influences on mitosis, induction of cell cycle arrest, and interference with cytokine pathways. All these mechanisms are associated with nephrotoxicity, hepatotoxicity, teratotoxicity, immunological toxicity, and neurotoxicity. OTA administration activates various mechanisms such as p38 MAPK, JNKs, and ERKs dysfunctions, BDNF disruption, TH overexpression, caspase-3 and 9 activation, and ERK-1/2 phosphorylation which ultimately lead to Alzheimer disease (AD) progression. The current review will focus on OTA in terms of recent discoveries in the field of molecular biology. The main aim is to investigate the underlying mechanisms of OTA in regard to genotoxicity and epigenetic modulations that lead to AD. Also, we will highlight the strategies for the purpose of attenuating the hazards posed by OTA exposure.

Implications of gut microbiota dysbiosis and metabolic changes in prion disease.

Evidence of the gut microbiota influencing neurodegenerative diseases has been reported for several neural diseases. However, there is little insight regarding the relationship between the gut microbiota and prion disease. Here, using fecal samples of 12 prion-infected mice and 25 healthy controls, we analyzed the structure of the gut microbiota and metabolic changes by 16S rRNA sequencing and LC-MS-based metabolomics respectively as multi-omic analyses. Additionally, SCFAs and common amino acids were detected by GC-MS and UPLC respectively. Enteric changes induced by prion disease affected both structure and abundances of the gut microbiota. The gut microbiota of infected mice displayed greater numbers of Proteobacteria and less Saccharibacteria at the phylum level and more Lactobacillaceae and Helicobacteraceae and less Prevotellaceae and Ruminococcaceae at the family level. A total of 145 fecal metabolites were found to be significantly different in prion infection, and most (114) of these were lipid metabolites. Using KEGG pathway enrichment analysis, we found that 3 phosphatidylcholine (PC) compounds significantly decreased and 4 hydrophobic bile acids significantly increased. Decreases of 8 types of short-chain acids (SCFAs) and increases of Cys and Tyr and decreases of His, Trp, and Arg were observed in prion infection. Correlation analysis indicated that the gut microbiota changes observed in our study may have been the shared outcome of prion disease. These findings suggest that prion disease can cause significant shifts in the gut microbiota. Certain bacterial taxa can then respond to the resulting change to the enteric environment by causing dramatic shifts in metabolite levels. Our data highlight the health impact of the gut microbiota and related metabolites in prion disease.

PP2Ac Modulates AMPK-Mediated Induction of Autophagy in Mycobacterium bovis-Infected Macrophages.

Mycobacterium bovis (M. bovis) is the causative agent of bovine tuberculosis in cattle population across the world. Human beings are at equal risk of developing tuberculosis beside a wide range of M. bovis infections in animal species. Autophagic sequestration and degradation of intracellular pathogens is a major innate immune defense mechanism adopted by host cells for the control of intracellular infections. It has been reported previously that the catalytic subunit of protein phosphatase 2A (PP2Ac) is crucial for regulating AMP-activated protein kinase (AMPK)-mediated autophagic signaling pathways, yet its role in tuberculosis is still unclear. Here, we demonstrated that M. bovis infection increased PP2Ac expression in murine macrophages, while nilotinib a tyrosine kinase inhibitor (TKI) significantly suppressed PP2Ac expression. In addition, we observed that TKI-induced AMPK activation was dependent on PP2Ac regulation, indicating the contributory role of PP2Ac towards autophagy induction. Furthermore, we found that the activation of AMPK signaling is vital for the regulating autophagy during M. bovis infection. Finally, the transient inhibition of PP2Ac expression enhanced the inhibitory effect of TKI-nilotinib on intracellular survival and multiplication of M. bovis in macrophages by regulating the host's immune responses. Based on these observations, we suggest that PP2Ac should be exploited as a promising molecular target to intervene in host-pathogen interactions for the development of new therapeutic strategies towards the control of M. bovis infections in humans and animals.

OPA1 overexpression ameliorates mitochondrial cristae remodeling, mitochondrial dysfunction, and neuronal apoptosis in prion diseases.

Prion diseases caused by the cellular prion protein (PrPC) conversion into a misfolded isoform (PrPSc) are associated with multiple mitochondrial damages. We previously reported mitochondrial dynamic abnormalities and cell death in prion diseases via modulation of a variety of factors. Optic atrophy 1 (OPA1) is one of the factors that control mitochondrial fusion, mitochondrial DNA (mtDNA) maintenance, bioenergetics, and cristae integrity. In this study, we observed downregulation of OPA1 in prion disease models in vitro and in vivo, mitochondria structure damage and dysfunction, loss of mtDNA, and neuronal apoptosis. Similar mitochondria findings were seen in OPA1-silenced un-infected primary neurons. Overexpression of OPA1 not only alleviated prion-induced mitochondrial network fragmentation and mtDNA loss, decrease in intracellular ATP, increase in ADP/ATP ratio, and decrease in mitochondrial membrane potential but also protected neurons from apoptosis by suppressing the release of cytochrome c from mitochondria to cytosol and activation of the apoptotic factor, caspase 3. Our results demonstrated that overexpression of OPA1 alleviates prion-associated mitochondrial network fragmentation and cristae remodeling, mitochondrial dysfunction, mtDNA depletion, and neuronal apoptosis, suggesting that OPA1 may be a novel and effective therapeutic target for prion diseases.

Detection of Cell-Free Mitochondrial DNA in Cerebrospinal Fluid of Creutzfeldt-Jakob Patients.

Background: The current diagnosis method for Creutzfeldt-Jakob disease (CJD) is post-mortem examination, so early detection of CJD has been historically problematic. Auxiliary detection of CJD based on changes in levels of components of the cerebrospinal fluid (CSF) has become a focus of research. In other neurodegenerative diseases such as Alzheimer's disease (AD), cell-free mitochondrial DNA (mtDNA) in the CSF of patients may serve as a biomarker that could facilitate early diagnosis and studies of the mechanisms underlying the disease. Methods: In this study, the cell-free mitochondrial DNA in the CSF of patients with sCJD and control patients was compared by digital droplet PCR. Results: The cell-free mitochondrial DNA copy number in the CSF of sCJD patients was significantly increased in comparison with that of the control group, and this difference was pathologically related to CJD. Conclusion: Therefore, we speculate that changes in cerebrospinal fluid mitochondrial DNA copy number play an important role in the study of CJD mechanism and diagnosis.

Nilotinib: A Tyrosine Kinase Inhibitor Mediates Resistance to Intracellular Mycobacterium Via Regulating Autophagy.

Nilotinib, a tyrosine kinase inhibitor, has been studied extensively in various tumor models; however, no information exists about the pharmacological action of nilotinib in bacterial infections. Mycobacterium bovis (M. bovis) and Mycobacterium avium subspecies paratuberculosis (MAP) are the etiological agents of bovine tuberculosis and Johne's disease, respectively. Although M. bovis and MAP cause distinct tissue tropism, both of them infect, reside, and replicate in mononuclear phagocytic cells of the infected host. Autophagy is an innate immune defense mechanism for the control of intracellular bacteria, regulated by diverse signaling pathways. Here we demonstrated that nilotinib significantly inhibited the intracellular survival and growth of M. bovis and MAP in macrophages by modulating host immune responses. We showed that nilotinib induced autophagic degradation of intracellular mycobacterium occurred via the inhibition of PI3k/Akt/mTOR axis mediated by abelson (c-ABL) tyrosine kinase. In addition, we observed that nilotinib promoted ubiquitin accumulation around M. bovis through activation of E3 ubiquitin ligase parkin. From in-vivo experiments, we found that nilotinib effectively controlled M. bovis growth and survival through enhanced parkin activity in infected mice. Altogether, our data showed that nilotinib regulates protective innate immune responses against intracellular mycobacterium, both in-vitro and in-vivo, and can be exploited as a novel therapeutic remedy for the control of M. bovis and MAP infections.

Combinatory FK506 and Minocycline Treatment Alleviates Prion-Induced Neurodegenerative Events via Caspase-Mediated MAPK-NRF2 Pathway.

Transcription factors play a significant role during the symptomatic onset and progression of prion diseases. We previously showed the immunomodulatory and nuclear factor of activated T cells' (NFAT) suppressive effects of an immunosuppressant, FK506, in the symptomatic stage and an antibiotic, minocycline, in the pre-symptomatic stage of prion infection in hamsters. Here we used for the first time, a combinatory FK506+minocycline treatment to test its transcriptional modulating effects in the symptomatic stage of prion infection. Our results indicate that prolonged treatment with FK506+minocycline was effective in alleviating astrogliosis and neuronal death triggered by misfolded prions. Specifically, the combinatory therapy with FK506+minocycline lowered the expression of the astrocytes activation marker GFAP and of the microglial activation marker IBA-1, subsequently reducing the level of pro-inflammatory cytokines interleukin 1 beta (IL-1ß) and tumor necrosis factor alpha (TNF-α), and increasing the levels of anti-inflammatory cytokines IL-10 and IL-27. We further found that FK506+minocycline treatment inhibited mitogen-activated protein kinase (MAPK) p38 phosphorylation, NF-kB nuclear translocation, caspase expression, and enhanced phosphorylated cAMP response element-binding protein (pCREB) and phosphorylated Bcl2-associated death promoter (pBAD) levels to reduce cognitive impairment and apoptosis. Interestingly, FK506+minocycline reduced mitochondrial fragmentation and promoted nuclear factor⁻erythroid2-related factor-2 (NRF2)-heme oxygenase 1 (HO-1) pathway to enhance survival. Taken together, our results show that a therapeutic cocktail of FK506+minocycline is an attractive candidate for prolonged use in prion diseases and we encourage its further clinical development as a possible treatment for this disease.

Molecular mechanisms underlying protective role of quercetin in attenuating Alzheimer's disease.

Quercetin belongs to the flavonoids family, which is present in most of the plants including fruits, vegetables, green tea and even in red wine having antioxidant activities. It is available as a food supplement in the market and has physiological health effects. Quercetin has anti-inflammatory, anticancer and anti-prostate activities along with its beneficial effects on high cholesterol, kidney transplantation, asthma, diabetes, viral infections, pulmonary, schizophrenia and cardiovascular diseases. Quercetin possesses scavenging potential of hydroxyl radical (OH-), hydrogen peroxide (H2O2), and superoxide anion (O2-). These reactive oxygen species (ROS) hampers lipid, protein, amino acids and deoxyribonucleic acid (DNA) processing leading to epigenetic alterations. Quercetin has the ability to combat these harmful effects. ROS plays a vital role in the progression of Alzheimer's disease (AD), and we propose that quercetin would be the best choice to overcome cellular and molecular signals in regulating normal physiological functions. However, data are not well documented regarding exact cellular mechanisms of quercetin. The neuroprotective effects of quercetin are mainly due to potential up- and/or down-regulation of cytokines via nuclear factor (erythroid-derived 2)-like 2 (Nrf2), Paraoxonase-2, c-Jun N-terminal kinase (JNK), Protein kinase C, Mitogen-activated protein kinase (MAPK) signalling cascades, and PI3K/Akt pathways. Therefore, the aim of the present review was to elaborate on the cellular and molecular mechanisms of the quercetin involved in the protection against AD.

Pterostilbene alleviates hydrogen peroxide-induced oxidative stress via nuclear factor erythroid 2 like 2 pathway in mouse preimplantation embryos.

Pterostilbene (PTS) in blueberries is a phytoalexin with antioxidant properties. PTS exerts strong cytoprotective effects on various cells via Nuclear Factor Erythroid 2 like 2 (NFE2L2) pathway. We evaluated the antioxidant PTS treatment in mouse preimplantation embryos. In vitro culture media were supplemented with different concentrations of PTS. Treatment of zygotes with 0.25 µM PTS improved the development of day 4 blastocysts (P < 0.05). Moreover, H2O2 treatment significantly increased the reactive oxygen species level and reduced the glutathione level in mouse blastocyst, whereas PTS treatment counteracted these effects. The fluorescence intensity of apoptotic positive cell was higher in the H2O2 group than in the PTS group. Furthermore, PTS-treated embryos significantly increased the protein expression of NFE2L2 in the nucleus and decreased Kelch-like ECH-associated protein1 (KEAP1). PTS treatment significantly increased the expression of downstream target genes involved in the NFE2L2 pathway, such as catalase (CAT), heme oxygenase1 (HMOX1), glutathione peroxidase (GPX), and superoxide dismutase (SOD); these genes confer cellular protection. In addition, PTS treatment significantly increased the expression of anti-apoptotic B-cell lymphoma 2 (BCL2), with a concomitant reduction in the apoptotic Bcl-2-associated X protein (BAX) and Caspase-3 genes in the embryo. PTS treatment also increased the protein expression of BCL2 and reduced the protein expression of BAX in the mouse embryo. In conclusion, PTS activated NFE2L2 signaling pathway in the development of mouse embryos by altering downstream expression of genes involved in the antioxidant mechanisms and apoptosis.

p62-Keap1-NRF2-ARE Pathway: A Contentious Player for Selective Targeting of Autophagy, Oxidative Stress and Mitochondrial Dysfunction in Prion Diseases.

Prion diseases are a group of fatal and debilitating neurodegenerative diseases affecting humans and animal species. The conversion of a non-pathogenic normal cellular protein (PrPc) into an abnormal infectious, protease-resistant, pathogenic form prion protein scrapie (PrPSc), is considered the etiology of these diseases. PrPSc accumulates in the affected individual's brain in the form of extracellular plaques. The molecular pathways leading to neuronal cell death in prion diseases are still unclear. The free radical damage, oxidative stress and mitochondrial dysfunction play a key role in the pathogenesis of the various neurodegenerative disorders including prion diseases. The brain is very sensitive to changes in the redox status. It has been demonstrated that PrPc behaves as an antioxidant, while the neurotoxic prion peptide PrPSc increases hydrogen peroxide toxicity in the neuronal cultures leading to mitochondrial dysfunction and cell death. The nuclear factor erythroid 2-related factor 2 (NRF2) is an oxidative responsive pathway and a guardian of lifespan, which protect the cells from free radical stress-mediated cell death. The reduced glutathione, a major small molecule antioxidant present in all mammalian cells, and produced by several downstream target genes of NRF2, counterbalances the mitochondrial reactive oxygen species (ROS) production. In recent years, it has emerged that the ubiquitin-binding protein, p62-mediated induction of autophagy, is crucial for NRF2 activation and elimination of mitochondrial dysfunction and oxidative stress. The current review article, focuses on the role of NRF2 pathway in prion diseases to mitigate the disease progression.

Regulation of MicroRNAs-Mediated Autophagic Flux: A New Regulatory Avenue for Neurodegenerative Diseases With Focus on Prion Diseases.

Prion diseases are fatal neurological disorders affecting various mammalian species including humans. Lack of proper diagnostic tools and non-availability of therapeutic remedies are hindering the control strategies for prion diseases. MicroRNAs (miRNAs) are abundant endogenous short non-coding essential RNA molecules that negatively regulate the target genes after transcription. Several biological processes depend on miRNAs, and altered profiles of these miRNAs are potential biomarkers for various neurodegenerative diseases, including prion diseases. Autophagic flux degrades the misfolded prion proteins to reduce chronic endoplasmic reticulum stress and enhance cell survival. Recent evidence suggests that specific miRNAs target and regulate the autophagic mechanism, which is critical for alleviating cellular stress. miRNAs-mediated regulation of these specific proteins involved in the autophagy represents a new target with highly significant therapeutic prospects. Here, we will briefly describe the biology of miRNAs, the use of miRNAs as potential biomarkers with their credibility, the regulatory mechanism of miRNAs in major neurodegenerative diseases such as Alzheimer's, Parkinson's, and prion diseases, degradation pathways for aggregated prion proteins, the role of autophagy in prion diseases. Finally, we will discuss the miRNAs-modulated autophagic flux in neurodegenerative diseases and employ them as potential therapeutic intervention strategy in prion diseases.

The NLRP3-Caspase 1 Inflammasome Negatively Regulates Autophagy via TLR4-TRIF in Prion Peptide-Infected Microglia.

Prion diseases are neurodegenerative disorders characterized by the accumulation of misfolded prion protein, spongiform changes in the brain, and brain inflammation as a result of the wide-spread activation of microglia. Autophagy is a highly conserved catabolic process for the clearance of cytoplasmic components, including protein aggregates and damaged organelles; this process also eliminates pathological PrPSc as it accumulates during prion infection. The NALP3 inflammasome is a multiprotein complex that is a component of the innate immune system and is responsible for the release of pro-inflammatory cytokines. Our previous study showed that the neurotoxic prion peptide PrP106-126 induces NALP3 inflammasome activation and subsequent IL-1ß release in microglia. Autophagy is involved in the regulation of the immune responses and inflammation in many diseases including neurodegenerative diseases. However, the relationship between autophagy and NALP3 inflammasome in prion diseases has not been investigated. In this study, we demonstrated that the processing and release of mature IL-1ß is significantly enhanced by the inhibition of autophagy. Conversely, gene-silencing of the NALP3 inflammasome promotes autophagy. Suppression of TRIF or TLR4 by siRNA attenuated PrP106-126-induced autophagy, which is indicating that the TLR4-TRIF signaling pathway is involved in PrP106-26-induced autophagy. Caspase 1 directly cleaved TRIF to diminish TLR-4-TRIF mediated autophagy. Our findings suggest that the inhibition of autophagy by NALP3 inflammasome is probably mediated by activated Caspase-1-induced TRIF cleavage. This is the first study reporting that the NALP3 inflammasome complex negatively regulates autophagy in response to PrP106-126 stimulation in microglia, and partly explains the mechanism of autophagy inhibition by Caspase-1 in PrP106-126-induced BV2 cell activation. Our findings suggest that autophagy up-regulation and inhibition of Caspase-1 may protect against prion-induced neuroinflammation and accelerate misfolded protein degradation and are potential therapeutic approaches for prion diseases.

miRNAs in Tuberculosis: New Avenues for Diagnosis and Host-Directed Therapy.

Tuberculosis (TB) is one of the most fatal infectious diseases and a leading cause of mortality, with 95% of these deaths occurring in developing countries. The causative agent, Mycobacterium tuberculosis (Mtb), has a well-established ability to circumvent the host's immune system for its intracellular survival. microRNAs (miRNAs) are small, non-coding RNAs having an important function at the post-transcriptional level and are involved in shaping immunity by regulating the repertoire of genes expressed in immune cells. It has been established in recent studies that the innate immune response against TB is significantly regulated by miRNAs. Moreover, differential expression of miRNA in Mtb infection can reflect the disease progression and may help distinguish between active and latent TB infection (LTBI). These findings encouraged the application of miRNAs as potential biomarkers. Similarly, active participation of miRNAs in modulation of autophagy and apoptosis responses against Mtb opens an exciting avenue for the exploitation of miRNAs as host directed therapy (HDT) against TB. Nanoparticles mediated delivery of miRNAs to treat various diseases has been reported and this technology has a great potential to be used in TB. In reality, this exploitation of miRNAs as biomarkers and in HDT is still in its infancy stage, and more studies using animal models mimicking human TB are advocated to assess the role of miRNAs as biomarkers and therapeutic targets. In this review, we attempt to summarize the recent advancements in the role of miRNAs in TB as immune modulator, miRNAs' capability to distinguish between active and latent TB and, finally, usage of miRNAs as therapeutic targets against TB.

Reduced glutathione alleviates tunicamycin-induced endoplasmic reticulum stress in mouse preimplantation embryos.

Endoplasmic reticulum (ER) stress, a dysfunction in protein-folding capacity, is involved in many pathological and physiological responses, including embryonic development. This study aims to determine the developmental competence, apoptosis, and stress-induced gene expression in mouse preimplantation embryos grown in an in vitro culture medium supplemented with different concentrations of the ER stress inducer tunicamycin (TM) and the antioxidant glutathione (GSH). Treatment of zygotes with 0.5 µg/ml TM significantly decreased (P < 0.05) the rate of blastocyst formation, whereas 1 mM GSH supplementation improved the developmental rate of blastocysts. Furthermore, TM treatment significantly increased (P < 0.05) the apoptotic index and reduced the total number of cells, whereas GSH significantly increased the total number of cells and decreased the apoptotic index. The expression levels of ER chaperones, including immunoglobulin-binding protein, activating transcription factor 6, double-stranded activated protein kinase-like ER kinase, activating transcription factor 4, and C/EBP homologous protein were significantly increased (P < 0.05) by TM, but significantly decreased (P < 0.05) by GSH treatment. A similar pattern was observed in the case of the pro-apoptotic gene, B cell lymphoma-associated X protein. The expression level of the anti-apoptotic gene B cell lymphoma 2, was decreased by TM, but significantly increased after co-treatment with GSH. In conclusion, GSH improves the developmental potential of mouse embryos and significantly alleviates ER stress.

IFN-ß: A Contentious Player in Host-Pathogen Interaction in Tuberculosis.

Tuberculosis (TB) is a major health threat to the human population worldwide. The etiology of the disease is Mycobacterium tuberculosis (Mtb), a highly successful intracellular pathogen. It has the ability to manipulate the host immune response and to make the intracellular environment suitable for its survival. Many studies have addressed the interactions between the bacteria and the host immune cells as involving many immune mediators and other cellular players. Interferon-ß (IFN-ß) signaling is crucial for inducing the host innate immune response and it is an important determinant in the fate of mycobacterial infection. The role of IFN-ß in protection against viral infections is well established and has been studied for decades, but its role in mycobacterial infections remains much more complicated and debatable. The involvement of IFN-ß in immune evasion mechanisms adopted by Mtb has been an important area of investigation in recent years. These advances have widened our understanding of the pro-bacterial role of IFN-ß in host-pathogen interactions. This pro-bacterial activity of IFN-ß appears to be correlated with its anti-inflammatory characteristics, primarily by antagonizing the production and function of interleukin 1ß (IL-1ß) and interleukin 18 (IL-18) through increased interleukin 10 (IL-10) production and by inhibiting the nucleotide-binding domain and leucine-rich repeat protein-3 (NLRP3) inflammasome. Furthermore, it also fails to provoke a proper T helper 1 (Th1) response and reduces the expression of major histocompatibility complex II (MHC-II) and interferon-γ receptors (IFNGRs). Here we will review some studies to provide a paradigm for the induction, regulation, and role of IFN-ß in mycobacterial infection. Indeed, recent studies suggest that IFN-ß plays a role in Mtb survival in host cells and its downregulation may be a useful therapeutic strategy to control Mtb infection.