Comparing mRNA expression and protein abundance in MDR Mycobacterium tuberculosis: Novel protein candidates, Rv0443, Rv0379 and Rv0147 as TB potential diagnostic or therapeutic targets

Tuberculosis (TB) is a sizable public health threat in the world. This study was conducted to determine the differential protein composition between susceptible and MDRTB strains. Tuberculosis proteins were extracted by Triton™ X-114 and ammonium sulfate. Two-dimensional gel electrophoresis protein spots were selected for identification by mass spectrometry and mRNA expression levels were measured by real- time PCR. 2DE-Western blot and T cell epitope prediction for identified proteins were made by the IEDB server. The result shows at least six protein spots (Rv0147, Rv3597c, Rv0379, Rv3699, Rv1392 and Rv0443) were differentially expressed in MDRTB isolates. However, difference in mRNA gene expression was not found in the six mRNA genes. 2DE-Western blot procedures indicated strong reaction against MDRTB proteins corresponds to 13, 16 and 55 kDa areas that might be used as new diagnostic tools. In conclusion, these MDRTB proteins identified in this study could be reliable TB diagnostic candidates or therapeutic targets.

Assessment of fecal Akkermansia muciniphila in patients with osteoporosis and osteopenia: a pilot study

OBJECTIVES

Osteoporosis is characterized by slow deterioration in bone mass and disruption of its structure, leading to an increased risk of bone fractures. Gut microbiota plays an important role in the transport and absorption of nutrients needed for bone health. Akkermansia muciniphila is one of the gut microbiota members that its beneficial role in prevention of metabolic disorder was suggested. The aim of the current pilot study was the assessment of fecal A. muciniphila in patients with osteoporosis and osteopenia.

METHODS

A total of 36 subjects including eight with osteoporosis (three men and five women), eight with osteopenia (two men and six women), and 20 normal controls (six men and 14 women) were selected. Microbial genome was extracted from fresh stool samples. The bacterial load was determined by quantitative real-time PCR using 16S rRNA specific primers.

RESULTS

The participants' mean age in the osteoporosis, osteopenia and control groups were 61.71, 45 and 45.05 years, respectively. The majority of osteoporosis patients were post-menopause women, while in osteopenia group was pre-menopause. There were significant differences in terms of age, T-score, Z-score, and menopause among groups (P value < 0.05). The presence of A. muciniphila was higher in the healthy group compared to osteopenia group; however, these differences were not statistically significant.

CONCLUSIONS

In conclusion, however, there was no statistically significant difference between the study groups; it seems that the load of A. muciniphila may be related to bone health. Further in vivo and in vitro studies are needed to investigate the immunological and biochemical pathways.

Effect of Akkermansia muciniphila, Faecalibacterium prausnitzii, and Their Extracellular Vesicles on the Serotonin System in Intestinal Epithelial Cells

The gastrointestinal (GI) tract is an essential reservoir of serotonin or 5-hydroxytryptamine (5-HT), which possesses a set of bacterial species communities. Intestinal microbiota has the ability to modulate the host's serotonin system. In this regard, we evaluated the effect of Akkermansia muciniphila and Faecalibacterium prausnitzii along with their extracellular vesicles (EVs) on serotonin system-related genes in human epithelial colorectal adenocarcinoma (Caco-2) cells. The differentiated Caco-2 cells were treated with A. muciniphila and F. prausnitzii with the multiplicity of infection ratio of 1 and 10 and the EV concentration of 1 μg/mL and 50 μg/mL, respectively. After 24 h, the serotonin level was quantified using an ELISA kit and also the gene expression of serotonin system-related genes was examined using the quantitative real-time PCR method. According to the results, treatment with A. muciniphila and F. prausnitzii-derived EVs increased the serotonin level, while none of the bacteria could affect the serotonin level in the Caco-2 cells. Both bacteria had significant effects on the mRNA expression of serotonin system-related genes in the Caco-2 cells. Moreover, we observed that A. muciniphila and F. prausnitzii-derived EVs could impact the expression of major genes involved in the serotonin system. Our findings showed that A. muciniphila and F. prausnitzii along with their EVs could modulate serotonin system-related genes; hence, they may be useful in microbiota modulation therapies to maintain the homeostasis of the serotonin system.

Strain-specific behavior of Mycobacterium tuberculosis in A549 lung cancer cell line

BACKGROUND

A growing body of evidence has shown the association between tuberculosis (TB) infection and lung cancer. However, the possible effect of strain-specific behavior of Mycobacterium tuberculosis (M.tb) population, the etiological agent of TB infection in this association has been neglected. In this context, this study was conducted to investigate this association with consideration of the genetic background of strains in the M.tb population.

RESULTS

We employed the elastic net penalized logistic regression model, as a statistical-learning algorithm for gene selection, to evaluate this association in 129 genes involved in TLRs and NF-κB signaling pathways in response to two different M.tb sub-lineage strains (L3-CAS1and L 4.5). Of the 129 genes, 21 were found to be associated with the two studied M.tb sub-lineages. In addition, MAPK8IP3 gene was identified as a novel gene, which has not been reported in previous lung cancer studies and may have the potential to be recognized as a novel biomarker in lung cancer investigation.

CONCLUSIONS

This preliminary study provides new insights into the mechanistic association between TB infection and lung cancer. Further mechanistic investigations of this association with a large number of M.tb strains, encompassing the other main M.tb lineages and using the whole transcriptome of the host cell are inevitable.

Tuberculosis under the Influence of COVID-19 Lockdowns: Lessons from Tehran, Iran

This study investigates the short-term effects of the coronavirus disease 2019 (COVID-19) pandemic lockdown on tracing and detection of tuberculosis (TB) patients in Tehran, Iran. Results of this study have demonstrated that due to the significant decrease in the identification of patients with suspected TB during the COVID-19 outbreak in Tehran, it is imperative that patients with suspected TB be tracked and diagnosed more quickly to make up for some of the decline in TB diagnosis in recent months and to recover lost cases.

An Overview on the Upper and Lower Airway Microbiome in Cystic Fibrosis Patients

BACKGROUND

In cystic fibrosis patients, the mucus is an excellent place for opportunistic bacteria and pathogens to cover. Chronic infections of upper and lower airways play a critical role in the mortality of cystic fibrosis. This study aimed to introduce the microbiota profiles in patients with cystic fibrosis.

MATERIALS AND METHODS

In this study, a comprehensive literature search was done for studies on upper and lower airway microbiota in cystic fibrosis patients. International and national databases were searched for the following MeSH words: microbiota, microbiome, upper airway, lower airway, cystic fibrosis, cystic fibrosis, upper airway microbiome, lower airway microbiome, microbiome pattern in cystic fibrosis, microbiome pattern in cystic fibrosis, upper airway microbiota, lower airway microbiota, and microbiota pattern.

RESULTS

Streptococcus spp. are in significantly higher relative abundance in infants and children with cystic fibrosis; however, Pseudomonas spp. are in higher relative abundance in adults with cystic fibrosis. Molecular diagnostic techniques can be remarkably accurate in detecting microbial strains.

CONCLUSION

For the detection and isolation of most bacterial species, independent-culture methods in addition to the standard culture method are recommended, and sampling should include both upper and lower airways.

The Anti-fibrotic Effects of Heat-Killed Akkermansia muciniphila MucT on Liver Fibrosis Markers and Activation of Hepatic Stellate Cells

Hepatic stellate cell (HSC) activation is a key phenomenon in development of liver fibrosis. Recently, Akkermansia muciniphila has been introduced as a next-generation microbe residing in the mucosal layer of the human gut. Due to the probable risks associated with the use of live probiotics, the tendency to use heat-killed bacteria has been raised. Herein, we investigated the potential anti-fibrotic effects of heat-killed A. muciniphila MucT on activation of HSCs. The human LX-2 cells were stimulated by various concentrations of LPS to evaluate the optimal concentration for HSC activation. Cell viability of LX-2 cells treated with LPS and heat-killed A. muciniphila MucT was measured by MTT assay. Scanning electron microscopy was used to analyze the morphology of heat-killed bacteria. Quiescent and LPS-stimulated LX-2 cells were coinfected with heat-killed A. muciniphila MucT. The gene expression of α-SMA, TIMP, Col1, TGF-β, TLR4, and PPARγ was analyzed using quantitative real-time PCR. Our results showed that LPS treatment led to a significant increase in fibrosis markers in a concentration-independent manner (P < 0.0001), and significantly downregulated the expression of PPARγ (P < 0.0001). The heat-killed A. muciniphila MucT could significantly modulate the expression of fibrosis markers particularly in MOI 10 (P < 0.0001), and reversed the HSC activation in LPS-stimulated LX-2 cells. In conclusion, we demonstrated that heat-killed A. muciniphila MucT was safe and capable to ameliorate LPS-induced HSC activation through modulation of fibrosis markers. Further in vivo studies are required to validate the anti-fibrotic properties of heat-killed A. muciniphila MucT.

Effects of Akkermansia muciniphila and Faecalibacterium prausnitzii on serotonin transporter expression in intestinal epithelial cells

Purpose

The highest level of peripheral serotonin in the body can be found in the gastrointestinal (GI) tract as its reservoir. There is complete interaction between human gastrointestinal microbiota and serotonin system. Serotonin in the GI is transferred by serotonin transporters (SERTs), which play a crucial role in the bioavailability of serotonin in the GI. SERT impairment is associated with the pathology of GI disorders. It is known that intestinal microbiota can regulate the SERT function. Therefore, it may be useful to regulate of SERT expression by modulation of microbiota and improvement of intestinal motility and GI sensation. In this study, we aimed to evaluate the effects of two next-generation probiotics, including Akkermansia muciniphila and Faecalibacterium prausnitzii, and their supernatants on SERT gene expression in human epithelial colorectal adenocarcinoma cells (Caco-2).

Methods

The Caco-2 cells were treated with multiplicity of infection (MOI) ratio of 100 of A. muciniphila and F. prausnitzii, as well as their supernatants. After 24 h, SERT gene expression was examined by quantitative real-time polymerase chain reaction (qRT-PCR) assay.

Results

A. muciniphila up-regulated the SERT mRNA level by 3.01 folds, compared to the control group. F. prausnitzii, similar to A. muciniphila, increased the expression of SERT gene in Caco-2 cells by 3.43 folds (P < 0.001). Moreover, the supernatants of A. muciniphila and F. prausnitzii significantly up-regulated the expression of SERT gene in the cell line by 2.4 and 5.7 folds, respectively, compared to the control group (P < 0.001).

Conclusions

The present results showed that A. muciniphila and F. prausnitzii, as well as their supernatants, increased the expression of SERT gene in Caco-2 cells. Therefore, they might be helpful in the microbiota-modulating treatment of inflammatory bowel diseases.

Assessment of Mouse Ileal loop Protection against Clinically Isolated Vibrio cholerae Outer Membrane Vesicles as a Vaccine Candidate

Cholera, a life-threatening disease caused by the Gram-negative bacterium Vibrio cholera, remains a concern in developing countries. The present study investigated the immunogenicity and protective immunity of outer membrane vesicles (OMVs) and combination of OMV and killed whole cells (WC) of a local strain isolated from the last outbreak in Iran in addition to reference and local strains of V. cholerae El Tor O1 in comparison to Dukoral vaccine in mice model. The protein content, morphology, and size of extracted OMVs were evaluated by electrophoresis and microscopic analyses, respectively. The serum titers of total immunoglobulin G (IgG), IgG1, IgG2a, and immunoglobulin A (IgA) in addition to secretory IgA and total IgG in different mice groups were determined by enzyme-linked immunosorbent assay (ELISA). In addition, fluid accumulation (FA) assay regarding the resistance to live strain of V. cholerae in ligated ileal loops was carried out to determine immunogenicity by OMV or combination of OMV and WC in comparison to that reported for Dukoral vaccine. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of purified OMVs indicated protein profiles within the range of 34-52 kDa. Furthermore, transmission electron microscopy demonstrated the spherical shaped vesicles of 50-200 nm. The results of ELISA showed significant titers of systemic and mucosal immune anti-OMV IgGs in immunized BALB/c mice with different vaccine regimens. Additionally, a notable increase in the FA ratio was demonstrated in this study. The obtained results of the present study revealed that the WC-OMV combination of local strain can induce a high level of antibody response indicating more protection than OMV or WC separately. Moreover, it can be considered an effective immunogen against V. cholerae.

Variation in Mycobacterium tuberculosis population structure in Iran: a systemic review and meta-analysis

Background

Acquiring comprehensive insight into the dynamics of Mycobacterium tuberculosis (Mtb) population structure is an essential step to adopt effective tuberculosis (TB) control strategies and improve therapeutic methods and vaccines. Accordingly, we performed this systematic review and meta-analysis to determine the overall prevalence of Mtb genotypes/ sublineages in Iran.

Methods

We carried out a comprehensive literature search using the international databases of MEDLINE and Scopus as well as Iranian databases. Articles published until April 2020 were selected based on the PRISMA flow diagram. The overall prevalence of the Mtb genotypes/sublineage in Iran was determined using the random effects or fixed effect model. The metafor R package and MedCalc software were employed for performing this meta-analysis.

Results

We identified 34 studies for inclusion in this study, containing 8329 clinical samples. Based on the pooled prevalence of the Mtb genotypes, NEW1 (21.94, 95% CI: 16.41–28.05%), CAS (19.21, 95% CI: 14.95–23.86%), EAI (12.95, 95% CI: 7.58–19.47%), and T (12.16, 95% CI: 9.18–15.50%) were characterized as the dominant circulating genotypes in Iran. West African (L 5/6), Cameroon, TUR and H37Rv were identified as genotypes with the lowest prevalence in Iran (< 2%). The highest pooled prevalence rates of multidrug-resistant strains were related to Beijing (2.52, 95% CI) and CAS (1.21, 95% CI).

Conclusions

This systematic review showed that Mtb populations are genetically diverse in Iran, and further studies are needed to gain a better insight into the national diversity of Mtb populations and their drug resistance pattern.

Modulation of serotonin signaling/metabolism by Akkermansia muciniphila and its extracellular vesicles through the gut-brain axis in mice

Several studies have reported that the host-microbe interactions in the gut modulate the host serotonin or 5-hydroxytryptamine (5-HT) system. Here, we evaluated the effects of Akkermansia muciniphila and its extracellular vesicles (EVs) on genes pertaining to the serotonergic system in the colon and hippocampus of mice. Male C57BL/6J mice were administered viable A. muciniphila and its EVs for 4 weeks. The serotonin levels in the colon, hippocampus, and serum of mice, as well as the human colon carcinoma cells (Caco-2), were measured by ELISA assays. Also, the effects of A. muciniphila and its EVs on the expression of serotonin system genes in the colon and hippocampus were examined. A. muciniphila and its EVs may have a biological effect on the induction of serotonin levels in the colon and hippocampus of mice. Also, EVs increased the serotonin level in the Caco-2 cell line. In contrast, both treatments decreased the serotonin level in the serum. Both the bacterium and its EVs had significant effects on the mRNA expression of genes, involved in serotonin signaling/metabolism in the colon and hippocampus of mice. Moreover, A. muciniphila and its EVs affected the mRNA expression of inflammatory cytokines (Il-10 and Tnf-α) in the colon, however, there is no significant difference in inflammatory cell infiltrate in the histopathology of the colon. The presence of A. muciniphila and its EVs in the gut promotes serotonin concentration, they also affect serotonin signaling/metabolism through the gut-brain axis and may be considered in new therapeutic strategies to ameliorate serotonin-related disorders.

The most important challenges ahead of microbiome pattern in the post era of the COVID-19 pandemic

As the ongoing COVID-19 pandemic posed a huge challenge to global public health, emphasis on personal hygiene caused extraordinary daily use of detergents and household cleaning products. Since antibacterial cleaning products have the capacity to change the environmental microbiome, increased exposure to household disinfectants could be associated with alterations in human microbiota composition and function. Moreover, the emerging links between household cleaning products and occurrence of non-communicable diseases and antibiotic resistance may involve the gut microbiome. The mediating effects of disturbed gut microbiota on associations between home use of cleaning products and life-long health consequences have been documented in some observational studies. Regarding the evidence associated reduction in exposure to non-pathogenic commensal bacteria and gut dysbiosis, further study is required to assess the effect of massive use of cleaning products during COVID-19 pandemic on long-term host health mediated by the altered microbiota. In this context, recommendations to consume probiotics and fermented foods might reverse the consequences by alleviating dysbiosis.

Association of microbiota-derived propionic acid and Alzheimer's disease; bioinformatics analysis

PURPOSE

Microbiota-derived metabolites could alter the brain tissue toward the neurodegeneration disease. This study aims to select the genes associated with Propionic acid (PPA) and compromise Alzheimer's disease (AD) to find the possible roles of PPA in AD pathogenesis.

METHODS

Microbiota-derived metabolites could alter the brain tissue toward the neurodegeneration disease. This study aims to select the genes associated with Propionic acid (PPA) and compromise Alzheimer's disease (AD) to find the possible roles of PPA in AD pathogenesis.

RESULTS

Amongst all genes associated with PPA and AD, 284 genes to be shared by searching databases and were subjected to further analysis. AD-PPA genes mainly involved in cancer, bacterial and virus infection, and neurological and non-neurological diseases. Gene Ontology and pathway analysis covered the most AD hallmark, such as amyloid formation, apoptosis, proliferation, inflammation, and immune system. Network analysis revealed hub and bottleneck genes. MCODE analysis also indicated the seed genes represented in the significant subnetworks. ICAM1 and CCND1 were the hub, bottleneck, and seed genes.

CONCLUSIONS

PPA interacted genes implicated in AD act through pathways initiate neuronal cell death. In sum up, AD-PPA shared genes exhibited evidence that supports the idea PPA secreted from bacteria could alter brain physiology toward the emerging AD signs. This idea needs to confirm by more future investigation in animal models.

Gut Microbiota and Serum Biomarker Analyses in Obese Patients Diagnosed with Diabetes and Hypothyroid Disorder

Background: Variations of serum biomarkers and bacterial diversity of the gastrointestinal tract in obese patients with diabetes or hypothyroid are poorly understood. The aim of this study was to provide recent findings in this regard. Methods: A total of 119 obese patients [17 with diabetes, 23 with hypothyroid, and 79 patients without either diabetes or hypothyroid (control)] were recruited in this study. Serum biomarkers such as biochemical, hormonal (insulin and glucagon), and cytokine levels [interleukin (IL)-6, IL-1β, tumor necrosis factor-alpha, IL-10, and transforming growth factor beta-1 (TGF-β1)] were measured under fasting conditions. Bacterial abundance of gut microbiota was also quantitated by real-time polymerase chain reaction using 16S rRNA gene-based specific primers. Results: Average value of blood sugar (P: 0.0184), hemoglobin A1c, insulin, homeostasis model assessment insulin resistance, TGF-β 1, IL-6, IL-1β, interferon gamma (P_{for each} < 0.001), and phylum Actinobacteria [odds ratio (OR): 1.5, P: 0.032] was significantly higher in diabetic versus control group. In contrast, the levels of IL-10 (P < 0.001), Firmicutes (OR: 0.6, P: 0.058), and Akkermansia muciniphila (OR: 0.4, P: 0.053) were significantly lower in diabetic versus control group. However, there was no statistically significant difference between the values in hypothyroid versus control group either in crude or adjusted models. Conclusion: While there are some relationships between serum biomarkers or bacterial abundance with diabetes prediction in obese patients, this prognostication is less likely in obese patients with hypothyroid. Further investigation is warranted in the application of identified preclinical biomarkers in the diagnosis of diabetes or hypothyroid in obese patients.

Global scientific output trend for Akkermansia muciniphila research: a bibliometric and scientometric analysis

BACKGROUND

Akkermansia muciniphila is an anaerobic bacterium residing in the healthy intestinal tract of host and its quantity has a negative correlation with various host diseases. This study for the first time provides a holistic bibliometric aspect of Akkermansi muciniphila research in the literature and shows the hot topic terms of these articles in any period of time.

METHODS

Scopus database was selected to retrieve documents relevant to Akkermansia muciniphila in any language up to 2019. The bibliometric profile of Akkermansia muciniphila articles including subject area, year distribution, citations, institutions, journals, authors, and countries was systematically characterized and the collaboration networks of authors and countries as well as the burst detection algorithm of the words in the titles, abstracts and keywords were visualized.

RESULTS

There is a progressive growing trend in research on Akkermansia from 2004 to 2019 with a total of 566 articles during this period. Out of 353 original articles, there are 194 animal studies (155 studies on mice) and 112 human studies. Also, 65 various diseases were investigated in these studies. The most focused conditions are obesity (71 articles) and type2 diabetes (39 articles). The United States is the leading country on Akkermansia publications (n = 132), followed by China (n = 95). Frontiers in Microbiology is the most dominant journal with 23 Akkermansia publications. In addition, "cancer" is the hot topic of recent Akkermansia research.

CONCLUSION

Akkermansia research is of progressive interest during the last decade and the studies on this subject move towards its relationship with cancer and its promising effect on health.

Pulmonary Infection Related to Mimivirus in Patient with Primary Ciliary Dyskinesia

Primary ciliary dyskinesia is a rare autosomal recessive disorder that causes oto-sino-pulmonary disease. We report a case of pulmonary infection related to mimivirus in a 10-year-old boy with primary ciliary dyskinesia that was identified using molecular techniques. Our findings indicate that the lineage C of mimivirus may cause pneumonia in humans.

A case report of wrist synovial infection due to Mycobacterium jacuzzii, Iran

Background

Mycobacterium jacuzzii (M. jacuzzii) was first isolated in 2003 by insertion of breast implants in Tel Aviv, Israel. In this case report, we describe our experience in detection of M. jacuzzii using phenotypic and genotypic test of wrist synovial sample.

Case presentation

A 73-year-old woman complained of pain and swelling in the right wrist for 4 months. Her body temperature was 37–38 °C, and symptoms, such as pain, swelling, and some movement limitation, were reported. Clinical laboratory parameters showed an elevated C-reactive protein (CRP) level, erythrocyte sedimentation rate (ESR), and white blood cells (WBC) count. The sequences of hsp65, rpoB, 16S rDNA, and sodA genes indicated very high homology to M. jacuzzii.

Conclusion

We report a case of synovial infection caused by M. jacuzzii in a patient with severe wrist pain in Iran, who was treated with amikacin, levofloxacin, and ethambutol. The outcomes of treatment after 8 months were positive, and no recurrence of infection was reported in the patient.

Intestinal Microbiota in Elderly Inpatients with Clostridioides difficile Infection

Purpose

The incidence of Clostridioides difficile infection (CDI) has been reported as 10-fold higher among the elderly population than in young adults. The aim of this study was to compare the targeted bacteria population in the fecal microbiota in two groups of hospitalized elderly, categorized according to CDI and non-CDI.

Patient and Methods

In this case–control study, 84 fecal samples of the 28 patients with CDI and 56 non-CDI patients (>65 years) were studied. C. difficile isolates were characterized by anaerobic culture and multiplex PCR. Quantitative PCR was used to analyze the bacterial elements.

Results

CDI group differed significantly for a prolonged hospital stay, previous surgery, residence in nursing home and exposure to a range of antibiotics including quinolone, clindamycin and cephalosporin. CDI group had significantly fewer members of Bacteroides spp., Clostridium cluster IV, Bifidobacterium spp., Faecalibacterium prausnitzii, and Prevotella spp. in their fecal microbiota than the control group (P < 0.05). The abundances of Akkermansia muciniphila, Lactobacillus spp., Escherichia coli and Klebsiella spp. were higher in group CDI compared with the control group (P < 0.05).

Conclusion

CDI status is associated with the abundance of some bacterial populations. In this study, an increase in Akkermansia muciniphila, Lactobacillus spp., and Enterobacteriaceae genus was highlighted in CDI patients. A reduction in butyrate-producing bacteria was found in CDI patients. The differences in the composition of fecal microbiota can help to understand how antimicrobial agents impact on gut homeostasis and lead to loss of colonization resistance to C. difficile.

Construction and assessment of the immunogenicity and bactericidal activity of fusion protein porin A from Neisseria meningitidis serogroups A and B admixed with OMV adjuvant as a novel vaccine candidate

Objectives

The porins A and B and also outer membrane vesicles (OMVs) of Neisseria meningitidis are used for vaccine purposes. In the present study, we aimed to design a new vaccine candidate based on a fusion of PorA of serogroups A and B of N. meningitidis admixed with OMV and evaluate it in an animal model.

Materials and Methods

After bioinformatic studies, a fusion protein composed of porin A from both serogroups A and B of N. meningitidis was constructed, expressed, and purified by nickel resins. Extraction of OMV of N. meningitidis was performed using a chemical method. The mice were vaccinated subcutaneously in different groups with mixtures of PorA proteins, OMV, and Freund's adjuvants. Then, the immune responses were measured using the ELISA method. Finally, serum bactericidal activity (SBA) procedure was applied to assay the activity of the immune responses in mice.

Results

Mice received the PorA protein plus Freund's adjuvant. Mice vaccinated with PorA fusion of serogroups A+B plus Freund's adjuvant produced more IgG, IgG1, and IgG2a than combinations admixed with OMV. Furthermore, the vaccinated mice tended to direct the IgG responses toward IgG1. Sera of the mice that received PorA+Freund's and those that received PorA+OMV produced higher bactericidal activity than the controls.

Conclusion

Fusion protein porin A could be a valuable target for developing vaccines against N. meningitidis. Although, Freund's adjuvant induced the strongest IgG responses, given that Freund's adjuvant has no human use, and OMV is a human adjuvant, OMV could be considered in vaccine design against N. meningitidis.

Effects of soy milk consumption on gut microbiota, inflammatory markers, and disease severity in patients with ulcerative colitis: a study protocol for a randomized clinical trial

Background

Several strategies are recommended to alleviate clinical symptoms of ulcerative colitis (UC). Soy milk may affect UC through its anti-inflammatory properties. However, no study has examined the effects of soy milk consumption on gut microbiota and inflammatory biomarkers in patients with UC. The current study will be done to examine the effects of soy milk consumption on UC symptoms, inflammation, and gut microbiota in patients with UC.

Methods

This study is a randomized clinical trial, in which thirty patients with mild to moderate severity of UC will be randomly allocated to receive either 250 mL/day soy milk plus routine treatments (n = 15) or only routine treatments (n = 15) for 4 weeks. Assessment of anthropometric measures and biochemical indicators including serum concentrations of high-sensitivity C-reactive protein (hs-CRP), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interferon gamma (IFN-γ) will be done at the study baseline and end of trial. In addition, the quantity of butyrate-producing bacteria including Clostridium cluster IV, Faecalibacterium prausnitzii, and Roseburia spp.; prebiotic bacteria including Lactobacillus spp. and Bifidobacteria spp.; and mucus-degrading bacteria including Akkermansia muciniphila, Bacteroides fragilis, and Ruminococcus spp., as well as calprotectin and lactoferrin levels, will be explored in fecal samples. Also, the Firmicutes to Bacteroidetes ratio which is of significant relevance in human gut microbiota composition will be assessed.

Discussion

Altered gut microbiota has been reported as an important contributing factor to inflammation in patients with inflammatory bowel disease (IBD). Soy milk contains several components such as phytoestrogens with potential anti-inflammatory properties. This product might affect gut microbiota through its protein and fiber content. Therefore, soy milk might beneficially affect systemic inflammation, gut microbiota, and then clinical symptoms in patients with UC.

Trial registration

Iranian Registry of Clinical Trials (www.irct.ir) IRCT20181205041859N1. Registered on 27 January 2019.

Stimulatory effects of Lactobacillus casei derived extracellular vesicles on toll-like receptor 9 gene expression and cytokine profile in human intestinal epithelial cells

Background

A complex community of microorganisms in the gastrointestinal (GI) tract, known as the gut microbiota, exerts major effects on gene expression and cytokine profile. Extracellular vesicles (EVs) which are produced by bacteria could be sensed by Toll like receptors (TLRs). The interaction between gut microbiota and TLRs affects homeostasis and immune responses. In this study, we evaluated TLR9 gene expression and cytokines level in Caco-2 cell line treated with Lactobacillus casei as one of the gut microbiota and its EVs.

Methods

In the present study, L. casei derived EVs was extracted via ultracentrifugation. The quality control assessment included the evaluation of physicochemical characteristics of EVs. For the treatment of Caco-2 cell line, L. casei and its EVs (100 and 150 μg/mL) were used. In addition, qRT-PCR assay was carried out to evaluate the mRNA expression of TLR9 gene. ELISA assay was also performed to determine the levels of IFN_γ, TNF-α, GM-CSF, IL-1α, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-12, IL-17A, and IL-10 cytokines.

Results

The results showed that L. casei slightly increased TLR9 gene expression in the Caco-2 cell line. It was also found that EVs at concentrations of 100 and 150 μg/mL could significantly decrease TLR9 gene expression. Furthermore, L. casei significantly increased IL-10 and IFN_γ levels. Based on the findings, the level of IL-17A, as a proinflammatory cytokine, decreased by L. casei. Both concentrations of EVs decreased the level of IFN_γ, while increasing the concentrations of IL-4 and IL-10. EVs from L. casei could modulate immune responses in the Caco-2 cell line. Both EVs and L. casei activated the expression and secretion of several cytokines.

Conclusions

L. casei and its EVs have pivotal role in the cross talk between gut microbiota and the host especially in the modulation of the immune system. This study shows for the first time the increasing level of anti-inflammatory cytokines by EVs released by L. casei. Based on the last studies on immunomodulatory effect of EVs on immune cells and our results in cell line level, we postulate that L. casei derived EVs could be possible candidates for the reduction of immune responses.

The regulation of Niemann-Pick C1-Like 1 (NPC1L1) gene expression in opposite direction by Bacteroides spp. and related outer membrane vesicles in Caco-2 cell line

Purpose

The intestine has substantial role in cholesterol homeostasis due to the presence of various cholesterol transporters and gut microbiota. Bacteroides spp. are important members of gut microbiota that employ outer membrane vesicles (OMVs) to interact with host. In this regard, we evaluated the effect of Bacteroides fragilis, Bacteroides thetaiotaomicron and related OMVs on the gene expression of important cholesterol transporters, Niemann-Pick C1-Like 1 (NPC1L1), ATP-binding cassette (ABCA1), and liver X receptors (LXRs) in Caco-2 cells.

Methods

OMVs were isolated from overnight brain heart infusion (BHI) broth of bacterial standard strains using deoxycholate and assessed by Scanning electron microscopy (SEM). The relative change in genes expression was assessed by Quantitative reverse transcription PCR (RT-qPCR) based on SYBR Green and 2^-∆∆ct method in Caco-2 cells that were treated with bacteria and OMVs. Data were statistically analyzed with GraphPad Prism software. Finally, pathway enrichment based on the studied genes was performed using Cytoscape plugin ClueGO.

Results

B. fragilis (P value = 0.002) and B. thetaiotaomicron (P value = 0.001) significantly reduced NPC1L1 gene expression in Caco-2 cells. Interestingly, NPC1L1 transcripts were significantly increased by both OMVs(P value = 0.04) (P value = 0.01). Also, LXRβ was significantly down regulated by B. thetaiotaomicron (P value = 0.02). ClueGO analysis on the studied genes demonstrated several functional groups which involve in lipid and cholesterol metabolism.

Conclusion

The opposite effect of B. fragilis, B. thetaiotaomicron and related OMVs on the NPC1L1 gene expression was observed in Caco-2 cells. Interestingly, these effects partially were in line with the alternation of LXRs expression. However, based on pathway enrichment analysis, further molecular investigations are required to elaborate in details the specific association between Bacteroides spp. and OMVs with regulation of cholesterol signaling pathways including cholesterol transport, lipid storage, lipid homeostasis and cholesterol homeostasis.