Hydroxytyrosol attenuates ethanol-induced liver injury by ameliorating steatosis, oxidative stress and hepatic inflammation by interfering STAT3/iNOS pathway

Objective: Hydroxytyrosol (HT) is a polyphenol with a wide range of biological activities. Excessive drinking can lead to oxidative stress and inflammation in the liver, which usually develop into alcohol liver disease (ALD). At present, there is no specific drug to treat ALD. In this paper, the protection effect of HT on ALD and the underline mechanism were studied.Methods: HepG2 cells were exposed to ethanol in vitro and C57BL/6J mice were fed with a Lieber-DeCarli ethanol liquid diet in vivo.Results: triglyceride (TG) level in serum and the expression of fatty acid synthase (FASN) were reduced significantly by the treatment with HT The acetaldehyde dehydrogenase (ALDH) activity was increased, the serum level of malondialdehyde (MDA) was decreased, catalase (CAT) and glutathione (GSH) were increased, suggesting that HT may reduce its oxidative damage to the body by promoting alcohol metabolism. Furthermore, according to the mRNA levels of tnf-α, il-6 and il-1β, HT inhibited ethanol-induced inflammation significantly. The anti-inflammatory mechanism of HT may be related to suppress the STAT3/iNOS pathway.Dissussion: Our study showed that HT could ameliorate ethanol-induced hepatic steatosis, oxidative stress and inflammation and provide a new candidate for the prevention and treatment of ALD.

Acupuncture improves the symptoms, intestinal microbiota, and inflammation of patients with mild to moderate Crohn's disease: A randomized controlled trial

BACKGROUND

The efficacy and mechanisms of acupuncture for Crohn's disease (CD) are not well understood. We investigated its effects on symptoms, intestinal microbiota, and circulating inflammatory markers in CD patients.

METHODS

This 48-week, randomized, sham controlled, parallel-group clinical trial was performed at a tertiary outpatient clinic in China. From April 2015 to November 2019, 66 patients (mean age 40·4, 62·1% were male, all were Han Chinese) with mild to moderate active CD and unresponsive to drug treatment were enrolled and randomly assigned equally to an acupuncture group or a sham group. The treatment group received 3 sessions of acupuncture plus moxibustion per week for 12 weeks and a follow-up of 36 weeks. Clinicaltrials.gov: NCT02559037.

FINDINGS

At week 12, the clinical remission rate (the primary outcome) and clinical response rate of acupuncture group were significantly higher than that of sham group, with a difference of 42·4% (95% CI: 20·1%-64·0%) and 45·5% (95% CI: 24·0%-66·9%), respectively, both of which maintained at week 48. The acupuncture group had significantly lower CD activity index and C-reactive protein level at week 12, which maintained at 36-week follow-up. The CD endoscopic index of severity, histopathological score, and recurrence rate at week 48 were significantly lower in acupuncture group. The number of operational taxonomic unit of intestinal microbiota and relative abundance of Faecalibacterium prausnitzii and Roseburia faecis were increased. Plasma diamine oxidase, lipopolysaccharide, and Th1/Th17 related cytokines were decreased in 12-week after acupuncture.

INTERPRETATION

Acupuncture was effective in inducing and maintaining remission in patients with active CD, which was associated with increased abundance of intestinal anti-inflammatory bacteria, enhanced intestinal barrier, and regulation of circulating Th1/Th17-related cytokines.

FUNDING

National Key Basic Research Program of China (2015CB554500 and 2009CB522900), Shanghai Rising-Star Program (19QA1408100).

Pulmonary delivery of siRNA against acute lung injury/acute respiratory distress syndrome

The use of small interfering RNAs (siRNAs) has been under investigation for the treatment of several unmet medical needs, including acute lung injury/acute respiratory distress syndrome (ALI/ARDS) wherein siRNA may be implemented to modify the expression of pro-inflammatory cytokines and chemokines at the mRNA level. The properties such as clear anatomy, accessibility, and relatively low enzyme activity make the lung a good target for local siRNA therapy. However, the translation of siRNA is restricted by the inefficient delivery of siRNA therapeutics to the target cells due to the properties of naked siRNA. Thus, this review will focus on the various delivery systems that can be used and the different barriers that need to be surmounted for the development of stable inhalable siRNA formulations for human use before siRNA therapeutics for ALI/ARDS become available in the clinic.

The cGAS-STING signaling in cardiovascular and metabolic diseases: Future novel target option for pharmacotherapy

The cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) signaling exert essential regulatory function in microbial-and onco-immunology through the induction of cytokines, primarily type I interferons. Recently, the aberrant and deranged signaling of the cGAS-STING axis is closely implicated in multiple sterile inflammatory diseases, including heart failure, myocardial infarction, cardiac hypertrophy, nonalcoholic fatty liver diseases, aortic aneurysm and dissection, obesity, etc. This is because of the massive loads of damage-associated molecular patterns (mitochondrial DNA, DNA in extracellular vesicles) liberated from recurrent injury to metabolic cellular organelles and tissues, which are sensed by the pathway. Also, the cGAS-STING pathway crosstalk with essential intracellular homeostasis processes like apoptosis, autophagy, and regulate cellular metabolism. Targeting derailed STING signaling has become necessary for chronic inflammatory diseases. Meanwhile, excessive type I interferons signaling impact on cardiovascular and metabolic health remain entirely elusive. In this review, we summarize the intimate connection between the cGAS-STING pathway and cardiovascular and metabolic disorders. We also discuss some potential small molecule inhibitors for the pathway. This review provides insight to stimulate interest in and support future research into understanding this signaling axis in cardiovascular and metabolic tissues and diseases.

Extracellular vesicle activities regulating macrophage- and tissue-mediated injury and repair responses

Macrophages are typically identified as classically activated (M1) macrophages and alternatively activated (M2) macrophages, which respectively exhibit pro- and anti-inflammatory phenotypes, and the balance between these two subtypes plays a critical role in the regulation of tissue inflammation, injury, and repair processes. Recent studies indicate that tissue cells and macrophages interact via the release of small extracellular vesicles (EVs) in processes where EVs released by stressed tissue cells can promote the activation and polarization of adjacent macrophages which can in turn release EVs and factors that can promote cell stress and tissue inflammation and injury, and vice versa. This review discusses the roles of such EVs in regulating such interactions to influence tissue inflammation and injury in a number of acute and chronic inflammatory disease conditions, and the potential applications, advantage and concerns for using EV-based therapeutic approaches to treat such conditions, including their potential role of drug carriers for the treatment of infectious diseases.

Functional metabolomics reveal the role of AHR/GPR35 mediated kynurenic acid gradient sensing in chemotherapy-induced intestinal damage

Intestinal toxicity induced by chemotherapeutics has become an important reason for the interruption of therapy and withdrawal of approved agents. In this study, we demonstrated that chemotherapeutics-induced intestinal damage were commonly characterized by the sharp upregulation of tryptophan (Trp)−kynurenine (KYN)−kynurenic acid (KA) axis metabolism. Mechanistically, chemotherapy-induced intestinal damage triggered the formation of an interleukin-6 (IL-6)−indoleamine 2,3-dioxygenase 1 (IDO1)−aryl hydrocarbon receptor (AHR) positive feedback loop, which accelerated kynurenine pathway metabolism in gut. Besides, AHR and G protein-coupled receptor 35 (GPR35) negative feedback regulates intestinal damage and inflammation to maintain intestinal integrity and homeostasis through gradually sensing kynurenic acid level in gut and macrophage, respectively. Moreover, based on virtual screening and biological verification, vardenafil and linagliptin as GPR35 and AHR agonists respectively were discovered from 2388 approved drugs. Importantly, the results that vardenafil and linagliptin significantly alleviated chemotherapy-induced intestinal toxicity in vivo suggests that chemotherapeutics combined with the two could be a promising therapeutic strategy for cancer patients in clinic. This work highlights GPR35 and AHR as the guardian of kynurenine pathway metabolism and core component of defense responses against intestinal damage.

Inhibitory effects of baicalein against herpes simplex virus type 1

Herpes simplex virus type 1 (HSV-1) is a ubiquitous and widespread human pathogen, which gives rise to a range of diseases, including cold sores, corneal blindness, and encephalitis. Currently, the use of nucleoside analogs, such as acyclovir and penciclovir, in treating HSV-1 infection often presents limitation due to their side effects and low efficacy for drug-resistance strains. Therefore, new anti-herpetic drugs and strategies should be urgently developed. Here, we reported that baicalein, a naturally derived compound widely used in Asian countries, strongly inhibited HSV-1 replication in several models. Baicalein was effective against the replication of both HSV-1/F and HSV-1/Blue (an acyclovir-resistant strain) in vitro. In the ocular inoculation mice model, baicalein markedly reduced in vivo HSV-1/F replication, receded inflammatory storm and attenuated histological changes in the cornea. Consistently, baicalein was found to reduce the mortality of mice, viral loads both in nose and trigeminal ganglia in HSV-1 intranasal infection model. Moreover, an ex vivo HSV-1-EGFP infection model established in isolated murine epidermal sheets confirmed that baicalein suppressed HSV-1 replication. Further investigations unraveled that dual mechanisms, inactivating viral particles and inhibiting IκB kinase beta (IKK-β) phosphorylation, were involved in the anti-HSV-1 effect of baicalein. Collectively, our findings identified baicalein as a promising therapy candidate against the infection of HSV-1, especially acyclovir-resistant strain.

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Baicalein is highly effective against HSV-1infection ex vivo and in vivo.

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Inactivation of viral particles and suppression of NF-κB activation were involved in the anti-viral effect of baicalein.

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Hence, our work offers experimental basis for baicalein as a potential drug in treating HSV-1 associated diseases.

Interacting with α 7 nAChR is a new mechanism for AChE to enhance the inflammatory response in macrophages

Acetylcholine (ACh) regulates inflammation via α7 nicotinic acetylcholine receptor (α7 nAChR). Acetylcholinesterase (AChE), an enzyme hydrolyzing ACh, is expressed in immune cells suggesting non-classical function in inflammatory responses. Here, the expression of PRiMA-linked G4 AChE was identified on the surface of macrophages. In lipopolysaccharide-induced inflammatory processes, AChE was upregulated by the binding of NF-κB onto the ACHE promotor. Conversely, the overexpression of G4 AChE inhibited ACh-suppressed cytokine release and cell migration, which was in contrast to that of applied AChE inhibitors. AChEmt, a DNA construct without enzymatic activity, was adopted to identify the protein role of AChE in immune system. Overexpression of G4 AChEmt induced cell migration and inhibited ACh-suppressed cell migration. The co-localization of α7 nAChR and AChE was found in macrophages, suggesting the potential interaction of α7 nAChR and AChE. Besides, immunoprecipitation showed a close association of α7 nAChR and AChE protein in cell membrane. Hence, the novel function of AChE in macrophage by interacting with α7 nAChR was determined. Together with hydrolysis of ACh, AChE plays a direct role in the regulation of inflammatory response. As such, AChE could serve as a novel target to treat age-related diseases by anti-inflammatory responses.

A metagenome-wide association study of gut microbiome and visceral fat accumulation

Purpose

Visceral fat is an independent risk factor for metabolic and cardiovascular disease. The study aimed to investigate the associations between gut microbiome and visceral fat.

Methods

We recruited 32 obese adults and 30 healthy controls at baseline. Among the obese subjects, 14 subjects underwent laparoscopic sleeve gastrectomy (LSG) and were followed 6 months after surgery. Abdominal visceral fat area (VFA) and subcutaneous fat area (SFA) were measured by magnetic resonance imaging. Waist, hipline, waist-to-hip ratio (WHR) and body mass index (BMI) were included as simple obese parameters. Gut microbiome was analyzed by metagenomic sequencing.

Results

Among the obese parameters, VFA had the largest number of correlations with the species that were differentially enriched between obese and healthy subjects, following by waist, WHR, BMI, hipline, and SFA. Within the species negatively correlated with VFA, Eubacterium eligens had the strongest correlation, following by Clostridium citroniae, C. symbiosum, Bacteroides uniformis, E. ventriosum, Ruminococcaceae bacterium D16, C. hathewayi, etc. C. hathewayi and C. citroniae were increased after LSG. Functional analyses showed that among all the obese parameters, VFA had strongest correlation coefficients with the obesity-related microbial pathways. Microbial pathways involved in carbohydrate fermentation and biosynthesis of L-glutamate and L-glutamine might contribute to visceral fat accumulation.

Conclusions

Visceral fat was more closely correlated with gut microbiome compared with subcutaneous fat, suggesting an intrinsic connection between gut microbiome and metabolic cardiovascular diseases. Specific microbial species and pathways which were closely associated with visceral fat accumulation might contribute to new targeted therapies for metabolic disorders.

Porcine mesothelium matrix as a biomaterial for wound healing applications

The increasing economic burden of wound healing in healthcare systems requires the development of functional therapies. Xenografts with preserved extracellular matrix (ECM) structure and biofunctional components overcome major limitations of autografts and allografts (e.g. availability) and artificial biomaterials (e.g. foreign body response). Although porcine mesothelium is extensively used in clinical practice, it is under-investigated for wound healing applications. Herein, we compared the biochemical and biological properties of the only two commercially available porcine mesothelium grafts (Meso Biomatrix® and Puracol® Ultra ECM) to traditionally used wound healing grafts (Endoform™, ovine forestomach and MatriStem®, porcine urinary bladder) and biomaterials (Promogran™, collagen/oxidized regenerated cellulose). The Endoform™ and the Puracol® Ultra ECM showed the highest (p<0.05) soluble collagen and elastin content. The MatriStem® had the highest (p<0.05) basic fibroblast growth factor (FGFb) content, whereas the Meso Biomatrix® had the highest (p<0.05) transforming growth factor beta-1 (TGF-β1) and vascular endothelial growth factor (VEGF) content. All materials showed tissue-specific structure and composition. The Endoform™ and the Meso Biomatrix® had some nuclei residual matter. All tissue grafts showed similar (p>0.05) response to enzymatic degradation, whereas the Promogran™ was not completely degraded by matrix metalloproteinase (MMP)-8 and was completely degraded by elastase. The Promogran™ showed the highest (p<0.05) permeability to bacterial infiltration. The Promogran™ showed by far the lowest dermal fibroblast and THP-1 attachment and growth. All tested materials showed significantly lower (p<0.05) tumor necrosis factor-alpha (TNF-α) expression than the lipopolysaccharides group. The MatriStem® and the Puracol® Ultra ECM promoted the highest (p<0.05) number of micro-vessel formation, whereas the Promogran™ the lowest (p<0.05). Collectively, these data confer that porcine mesothelium has the potential to be used as a wound healing material, considering its composition, resistance to enzymatic degradation, cytocompatibility, and angiogenic potential.

Edaravone protects rat astrocytes from oxidative or neurotoxic inflammatory insults by restoring Akt/Bcl-2/Caspase-3 signaling axis

Astrocytes are the major glia cells in the central nervous system (CNS). Increasing evidence indicates that more than to be safe-guard and supporting cells for neurons, astrocytes play a broad spectrum of neuroprotective and pathological functions. Thus, they are compelling models to decipher mechanistic insights of glia cells to CNS insults and for the development of drugs. Edaravone is a free radical scavenger with the capacity to eliminate hydroxyl radicals and lipid peroxides. In this study, we examined the neuroprotective effects of edaravone in rat astrocytes challenged by hydrogen peroxide (H₂O₂) or bacterial lipopolysaccharides (LPS), respectively. We discovered that edaravone attenuated H₂O₂-induced oxidative stress by reactivating the Akt signaling axis and antagonistically restoring the expression of apoptosis associated regulators such as Bcl-2 and Caspase-3. Consistently, inhibition of Akt signaling by LY294002 attenuated the anti-oxidative activity of edaravone. In addition, edaravone mitigated LPS-induced morphological changes in astrocytes and alleviated the inflammatory activation and expression of TNF-α, IL-1β, IL-6 and NOS2. In summary, our data suggested that edavarone effectively protects astrocytes from oxidative stress or infectious insults, which may pave a new avenue for its application in preclinical research and human disease therapeutics.

Neuropeptides in gut-brain axis and their influence on host immunity and stress

In recent decades, neuropeptides have been found to play a major role in communication along the gut-brain axis. Various neuropeptides are expressed in the central and peripheral nervous systems, where they facilitate the crosstalk between the nervous systems and other major body systems. In addition to being critical to communication from the brain in the nervous systems, neuropeptides actively regulate immune functions in the gut in both direct and indirect ways, allowing for communication between the immune and nervous systems. In this mini review, we discuss the role of several neuropeptides, including calcitonin gene-related peptide (CGRP), pituitary adenylate cyclase-activating polypeptide (PACAP), corticotropin-releasing hormone (CRH) and phoenixin (PNX), in the gut-brain axis and summarize their functions in immunity and stress. We choose these neuropeptides to highlight the diversity of peptide communication in the gut-brain axis.

Intestinal-level anti-inflammatory bioactivities of catechin-rich green tea: Rationale, design, and methods of a double-blind, randomized, placebo-controlled crossover trial in metabolic syndrome and healthy adults

Metabolic endotoxemia initiates low-grade chronic inflammation in metabolic syndrome (MetS) and provokes the progression towards more advanced cardiometabolic disorders. Our recent works in obese rodent models demonstrate that catechin-rich green tea extract (GTE) improves gut barrier integrity to alleviate the translocation of gut-derived endotoxin and its consequent pro-inflammatory responses mediated through Toll-like receptor-4/nuclear factor κB (TLR4/NFκB) signaling. The objective of this clinical trial is to establish the efficacy of GTE to alleviate metabolic endotoxemia-associated inflammation in persons with MetS by improving gut barrier function. We plan a double-blind, placebo-controlled cross-over trial in persons with MetS and age- and gender-matched healthy persons (18–65 y; n = 20/group) who will receive a low-energy GTE-rich (1 g/day; 890 mg total catechins) confection snack food while following a low-polyphenol diet for 28 days. Assessments will include measures of circulating endotoxin (primary outcome) and secondary outcomes including biomarkers of endotoxin exposure, region-specific measures of intestinal permeability, gut microbiota composition, diversity, and functions, intestinal and systemic inflammatory responses, and catechins and microbiota-derived catechin metabolites. Study outcomes will provide the first report of the GTE-mediated benefits that alleviate gut barrier dysfunction in relation to endotoxemia-associated inflammation in MetS persons. This is expected to help establish an effective dietary strategy to mitigate the growing burden of MetS that currently affects ~35% of Americans.

Kinsenoside attenuates osteoarthritis by repolarizing macrophages through inactivating NF-κB/MAPK signaling and protecting chondrocytes

The objective was to investigate the effect of kinsenoside (Kin) treatments on macrophage polarity and evaluate the resulting protection of chondrocytes to attenuate osteoarthritis (OA) progression. RAW264.7 macrophages were polarized to M1/M2 subtypes then administered with different concentrations of Kin. The polarization transitions were evaluated with quantitative real-time polymerase chain reaction (qRT-PCR), confocal observation and flow cytometry analysis. The mechanism of Kin repolarizing M1 macrophages was evaluated by Western blot. Further, macrophage conditioned medium (CM) and IL-1β were administered to chondrocytes. Micro-CT scanning and histological observations were conducted in vivo on anterior cruciate ligament transection (ACLT) mice with or without Kin treatment. We found that Kin repolarized M1 macrophages to the M2 phenotype. Mechanistically, Kin inhibited the phosphorylation of IκBα, which further reduced the downstream phosphorylation of P65 in nuclear factor-κB (NF-κB) signaling. Moreover, Kin inhibited mitogen-activated protein kinases (MAPK) signaling molecules p-JNK, p-ERK and p-P38. Additionally, Kin attenuated macrophage CM and IL-1β-induced chondrocyte damage. In vivo, Kin reduced the infiltration of M1 macrophages, promoted M2 macrophages in the synovium, inhibited subchondral bone destruction and reduced articular cartilage damage induced by ACLT. All the results indicated that Kin is an effective therapeutic candidate for OA treatment.

Use of Toll-like receptor assays for the detection of bacterial contaminations in icodextrin batches released for peritoneal dialysis

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Monocyte test assays were poorly efficient for the detection of little bacterial contamination in icodextrin batches.

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TLR2- and TLR4-transfected cell lines were appropriate for detecting PGN and LPS contaminations.

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Mutanolysin treatment of icodextrins enhanced the response of TLR2-transfected cells to contaminating PGN.

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Using TLR-transfected cell lines is a valuable approach for selecting icodextrin batches for peritoneal dialysis solutions.

Icodextrin is a starch derivative used for preparing solutions of peritoneal dialysis. Unfortunately, peptidoglycans (PGN) and lipopolysaccharides (LPS) have been reported to contaminate certain icodextrin batches and to contribute to the development of sterile peritonitis. The decision of selecting or rejecting icodextrin batches is however difficult, because of limitations in the detection of these bacterial contaminants. Besides monocyte activation tests of cytokine release, a number of bio-assays using stably TLR-transfected cell lines have been developed. Here, we compared the efficacy of TLR2- and TLR4-transfected cells to detect bacterial contamination with the responses of monocytes exposed to the same icodextrin samples. In contrast to monocyte models of cytokine release, we found that TLR2- and TLR4-transfected cell lines are highly sensitive to detect little PGN and LPS contaminations in the presence of icodextrin. With the intent to increase PGN reactivity, mutanolysin was used to generate soluble fragments in icodextrin samples. We found that such an enzymatic treatment led to an enhanced response of TLR2-transfected cells, even though parental icodextrin samples were poorly reactive. Altogether, these findings indicate that the use of TLR2- and TLR4-transfected cell lines is a valuable approach for helping to the decision of selecting icodextrin batches for peritoneal dialysis.

Exosomes as therapeutic drug carriers and delivery vehicles across biological membranes: current perspectives and future challenges

Exosomes are small intracellular membrane-based vesicles with different compositions that are involved in several biological and pathological processes. The exploitation of exosomes as drug delivery vehicles offers important advantages compared to other nanoparticulate drug delivery systems such as liposomes and polymeric nanoparticles; exosomes are non-immunogenic in nature due to similar composition as body׳s own cells. In this article, the origin and structure of exosomes as well as their biological functions are outlined. We will then focus on specific applications of exosomes as drug delivery systems in pharmaceutical drug development. An overview of the advantages and challenges faced when using exosomes as a pharmaceutical drug delivery vehicles will also be discussed.

Glutamine up-regulates MAPK phosphatase-1 induction via activation of Ca2+→ ERK cascade pathway

The non-essential amino acid L-glutamine (Gln) displays potent anti-inflammatory activity by deactivating p38 mitogen activating protein kinase and cytosolic phospholipase A₂ via induction of MAPK phosphatase-1 (MKP-1) in an extracellular signal-regulated kinase (ERK)-dependent way. In this study, the mechanism of Gln-mediated ERK-dependency in MKP-1 induction was investigated. Gln increased ERK phosphorylation and activity, and phosphorylations of Ras, c-Raf, and MEK, located in the upstream pathway of ERK, in response to lipopolysaccharidein vitro and in vivo. Gln-induced dose-dependent transient increases in intracellular calcium ([Ca²⁺]_i) in MHS macrophage cells. Ionomycin increased [Ca²⁺]_i and activation of Ras → ERK pathway, and MKP-1 induction, in the presence, but not in the absence, of LPS. The Gln-induced pathways involving Ca²⁺→ MKP-1 induction were abrogated by a calcium blocker. Besides Gln, other amino acids including L-phenylalanine and l-cysteine (Cys) also induced Ca²⁺ response, activation of Ras → ERK, and MKP-1 induction, albeit to a lesser degree. Gln and Cys were comparable in suppression against 2, 4-dinitrofluorobenzene-induced contact dermatitis. Gln-mediated, but not Cys-mediated, suppression was abolished by MKP-1 small interfering RNA. These data indicate that Gln induces MKP-1 by activating Ca²⁺→ ERK pathway, which plays a key role in suppression of inflammatory reactions.

Proprotein convertase 1/3 inhibited macrophages: A novel therapeutic based on drone macrophages

We demonstrated here thanks to proteomic, that proprotein convertase 1/3 knockdown macrophages present all the characteristic of activated pro-inflammatory macrophages. TLR4 and TLR9 signaling pathways can be enhanced leading to the secretion of pro-inflammatory factors and antitumor factors. We can control their activation by controlling one enzyme, PC1/3. In a tumor context, PC1/3 inhibition in macrophages may reactivate them and lead to a cytokine storm after stimulation "at distance" with a TLR ligand. Therefore, we name these proprotein convertase inhibited macrophages the "drone macrophages". They constitute an innovative cell therapy to treat efficiently tumors.

A High Level of Intestinal Alkaline Phosphatase Is Protective Against Type 2 Diabetes Mellitus Irrespective of Obesity

Mice deficient in intestinal alkaline phosphatase (IAP) develop type 2 diabetes mellitus (T2DM). We hypothesized that a high level of IAP might be protective against T2DM in humans. We determined IAP levels in the stools of 202 diabetic patients and 445 healthy non-diabetic control people. We found that compared to controls, T2DM patients have approx. 50% less IAP (mean +/- SEM: 67.4 +/- 3.2 vs 35.3 +/- 2.5 U/g stool, respectively; p < 0.000001) indicating a protective role of IAP against T2DM. Multiple logistic regression analyses showed an independent association between the IAP level and diabetes status. With each 25 U/g decrease in stool IAP, there is a 35% increased risk of diabetes. The study revealed that obese people with high IAP (approx. 65 U/g stool) do not develop T2DM. Approx. 65% of the healthy population have < 65.0 U/g stool IAP, and predictably, these people might have 'the incipient metabolic syndrome', including 'incipient diabetes', and might develop T2DM and other metabolic disorders in the near future. In conclusion, high IAP levels appear to be protective against diabetes irrespective of obesity, and a 'temporal IAP profile' might be a valuable tool for predicting 'the incipient metabolic syndrome', including 'incipient diabetes'.

Claudin-2 as a mediator of leaky gut barrier during intestinal inflammation

The epithelial tight junction determines the paracellular water and ion movement in the intestine and also prevents uptake of larger molecules, including antigens, in an uncontrolled manner. Claudin-2, one of the 27 mammalian claudins regulating that barrier function, forms a paracellular channel for small cations and water. It is typically expressed in leaky epithelia like proximal nephron and small intestine and provides a major pathway for the paracellular transport of sodium, potassium, and fluid. In intestinal inflammation (Crohn's disease, ulcerative colitis), immune-mediated diseases (celiac disease), and infections (HIV enteropathy), claudin-2 is upregulated in small and large intestine and contributes to diarrhea via a leak flux mechanism. In parallel to that upregulation, other epithelial and tight junctional features are altered and the luminal uptake of antigenic macromolecules is enhanced, for which claudin-2 may be partially responsible through induction of tight junction strand discontinuities.

Deciphering the dual effect of lipopolysaccharides from plant pathogenic Pectobacterium

Lipopolysaccharides (LPS) are a component of the outer cell surface of almost all Gram-negative bacteria and play an essential role for bacterial growth and survival. Lipopolysaccharides represent typical microbe-associated molecular pattern (MAMP) molecules and have been reported to induce defense-related responses, including the expression of defense genes and the suppression of the hypersensitive response in plants. However, depending on their origin and the challenged plant, LPS were shown to have complex and different roles. In this study we showed that LPS from plant pathogens Pectobacterium atrosepticum and Pectobacterium carotovorum subsp. carotovorum induce common and different responses in A. thaliana cells when compared to those induced by LPS from non-phytopathogens Escherichia coli and Pseudomonas aeruginosa. Among common responses to both types of LPS are the transcription of defense genes and their ability to limit of cell death induced by Pectobacterium carotovorum subsp carotovorum. However, the differential kinetics and amplitude in reactive oxygen species (ROS) generation seemed to regulate defense gene transcription and be determinant to induce programmed cell death in response to LPS from the plant pathogenic Pectobacterium. These data suggest that different signaling pathways could be activated by LPS in A. thaliana cells.

Biophysical analysis of the interaction of the serum protein human β2GPI with bacterial lipopolysaccharide

There are several human serum proteins for which no clear role is yet known. Among these is the abundant serum protein beta2-glycoprotein-I (β2GPI), which is known to bind to negatively charged phospholipids as well as to bacterial lipopolysaccharides (LPS), and was therefore proposed to play a role in the immune response. To understand the details of these interactions, a biophysical analysis of the binding of β2GPI to LPS and phosphatidylserine (PS) was performed. The data indicate only a moderate tendency of the protein (1) to influence the LPS-induced cytokine production in vitro, (2) to react exothermally with LPS in a non-saturable way, and (3) to change its local microenvironment upon LPS association. Additionally, we found that the protein binds more strongly to phosphatidylserine (PS) than to LPS. Furthermore, β2GPI converts the LPS bilayer aggregates into a stronger multilamellar form, and reduces the fluidity of the hydrocarbon moiety of LPS due to a rigidification of the acyl chains. From these data it can be concluded that β2GPI plays a role as an immune-modulating agent, but there is much less evidence for a role in immune defense against bacterial toxins such as LPS.

Gut-liver axis: role of inflammasomes

Inflammasomes are large multiprotein complexes that have the ability to sense intracellular danger signals through special NOD-like receptors or NLRs. They include NLRP3, NLRC4, AIM2 and NLRP6. They are involved in recognizing diverse microbial (bacteria, viruses, fungi and parasites), stress and damage signals, which result in direct activation of caspase-1, leading to secretion of potent pro-inflammatory cytokines and pyroptosis. NLRP3 is the most studied antimicrobial immune response inflammasome. Recent studies reveal expression of inflammasomes in innate immune response cells including monocytes, macrophages, neutrophils, and dendritic cells. Inflammasome deficiency has been linked to alterations in the gastrointestinal microflora. Alterations in the microbiome population and/or changes in gut permeability promote microbial translocation into the portal circulation and thus directly to the liver. Gut derived lipopolysaccharides (LPS) play a significant role in several liver diseases. Recent advancements in the sequencing technologies along with improved methods in metagenomics and bioinformatics have provided effective tools for investigating the 10(14) microorganisms of the human microbiome that inhabit the human gut. In this review, we examine the significance of inflammasomes in relation to the gut microflora and liver. This review also highlights the emerging functions of human microbiota in health and liver diseases.