Trichothecene mycotoxins activate NLRP3 inflammasome through a P2X7 receptor and Src tyrosine kinase dependent pathway

Real-life exposure to Fusarium toxins deoxynivalenol and zearalenone triggers apoptosis and activates NLRP3 inflammasome in bovine primary theca cells

Cattle are deemed less susceptible to mycotoxins due to the limited internal exposure resulting from rumen microbiota activity. However, the significant amounts of Fusarium mycotoxins deoxynivalenol (DON) and zearalenone (ZEN) frequently detected in bovine follicular fluid samples suggest that they could affect ovarian function. Both mycotoxins trigger several patterns of cell death and activate the NLRP3 inflammasome in the intestine. In vitro studies have reported a number of adverse effects on bovine oocytes. However, the biological relevance of such findings with regard to realistic concentrations of DON and ZEN in bovine follicular fluid is still not clear. Hence, it is important to better characterize the effects of dietary exposure to DON and ZEN on the bovine ovary. Using bovine primary theca cells, this study investigated the effects of real-life patterns for bovine ovary exposure to DON and ZEN, but also DON metabolite DOM-1, on cell death and NLRP3 inflammasome activation. Exposure to DON starting from 0.1 μM significantly decreased theca cell viability. The kinetics of phosphatidylserine translocation and loss of membrane integrity showed that ZEN and DON, but not DOM-1, induce an apoptotic phenotype. qPCR analysis of the expression of NLRP3, PYCARD, IL-1β, IL-18, and GSDMD in primary theca cells at concentrations of mycotoxin previously reported in cow follicular fluid clearly indicated that DON and DOM-1 individually and in mixture, but not ZEN, activate NLRP3 inflammasome. Altogether, these results suggest that real-life dietary exposure of cattle to DON may induce inflammatory disorders in the ovary.

Bi-Directional Relationship Between Autophagy and Inflammasomes in Neurodegenerative Disorders

The innate immune system, as the first line of cellular defense, triggers a protective response called inflammation when encountered with invading pathogens. Inflammasome is a multi-protein cytosolic signaling complex that induces inflammation and is critical for inflammation-induced pyroptotic cell death. Inflammasome activation has been found associated with neurodegenerative disorders (NDs), inflammatory diseases, and cancer. Autophagy is a crucial intracellular quality control and homeostasis process which removes the dysfunctional organelles, damaged proteins, and pathogens by sequestering the cytosolic components in a double-membrane vesicle, which eventually fuses with lysosome resulting in cargo degradation. Autophagy disruption has been observed in many NDs presented with persistent neuroinflammation and excessive inflammasome activation. An interplay between inflammation activation and the autophagy process has been realized over the last decade. In the case of NDs, autophagy regulates neuroinflammation load and cellular damage either by engulfing the misfolded protein deposits, dysfunctional mitochondria, or the inflammasome complex itself. A healthy two-way regulation between both cellular processes has been realized for cell survival and cell defense during inflammatory conditions. Therefore, clinical interest in the modulation of inflammasome activation by autophagy inducers is rapidly growing. In this review, we discuss the structural basis of inflammasome activation and the mechanistic ideas of the autophagy process in NDs. Along with comments on multiple ways of neuroinflammation regulation by microglial autophagy, we also present a perspective on pharmacological opportunities in this molecular interplay pertaining to NDs.

Mold, Mycotoxins and a Dysregulated Immune System: A Combination of Concern?

Fungi represent one of the most diverse and abundant eukaryotes on earth. The interplay between mold exposure and the host immune system is still not fully elucidated. Literature research focusing on up-to-date publications is providing a heterogenous picture of evidence and opinions regarding the role of mold and mycotoxins in the development of immune diseases. While the induction of allergic immune responses by molds is generally acknowledged, other direct health effects like the toxic mold syndrome are controversially discussed. However, recent observations indicate a particular importance of mold/mycotoxin exposure in individuals with pre-existing dysregulation of the immune system, due to exacerbation of underlying pathophysiology including allergic and non-allergic chronic inflammatory diseases, autoimmune disorders, and even human immunodeficiency virus (HIV) disease progression. In this review, we focus on the impact of mycotoxins regarding their impact on disease progression in pre-existing immune dysregulation. This is complemented by experimental in vivo and in vitro findings to present cellular and molecular modes of action. Furthermore, we discuss hypothetical mechanisms of action, where evidence is missing since much remains to be discovered.

The receptor-type protein tyrosine phosphatase CD45 promotes onset and severity of IL-1β-mediated autoinflammatory osteomyelitis

A number of human autoinflammatory diseases manifest with severe inflammatory bone destruction. Mouse models of these diseases represent valuable tools that help us to understand molecular mechanisms triggering this bone autoinflammation. The Pstpip2^cmo mouse strain is among the best characterized of these; it harbors a mutation resulting in the loss of adaptor protein PSTPIP2 and development of autoinflammatory osteomyelitis. In Pstpip2^cmo mice, overproduction of interleukin-1β (IL-1β) and reactive oxygen species by neutrophil granulocytes leads to spontaneous inflammation of the bones and surrounding soft tissues. However, the upstream signaling events leading to this overproduction are poorly characterized. Here, we show that Pstpip2^cmo mice deficient in major regulator of Src-family kinases (SFKs) receptor-type protein tyrosine phosphatase CD45 display delayed onset and lower severity of the disease, while the development of autoinflammation is not affected by deficiencies in Toll-like receptor signaling. Our data also show deregulation of pro-IL-1β production by Pstpip2^cmo neutrophils that are attenuated by CD45 deficiency. These data suggest a role for SFKs in autoinflammation. Together with previously published work on the involvement of protein tyrosine kinase spleen tyrosine kinase, they point to the role of receptors containing immunoreceptor tyrosine-based activation motifs, which after phosphorylation by SFKs recruit spleen tyrosine kinase for further signal propagation. We propose that this class of receptors triggers the events resulting in increased pro-IL-1β synthesis and disease initiation and/or progression.

The Natterin Proteins Diversity: A Review on Phylogeny, Structure, and Immune Function

Since the first record of the five founder members of the group of Natterin proteins in the venom of the medically significant fish Thalassophryne nattereri, new sequences have been identified in other species. In this work, we performed a detailed screening using available genome databases across a wide range of species to identify sequence members of the Natterin group, sequence similarities, conserved domains, and evolutionary relationships. The high-throughput tools have enabled us to dramatically expand the number of members within this group of proteins, which has a remote origin (around 400 million years ago) and is spread across Eukarya organisms, even in plants and primitive Agnathans jawless fish. Overall, the survey resulted in 331 species presenting Natterin-like proteins, mainly fish, and 859 putative genes. Besides fish, the groups with more species included in our analysis were insects and birds. The number and variety of annotations increased the knowledge of the obtained sequences in detail, such as the conserved motif AGIP in the pore-forming loop involved in the transmembrane barrel insertion, allowing us to classify them as important constituents of the innate immune defense system as effector molecules activating immune cells by interacting with conserved intracellular signaling mechanisms in the hosts.

Melinacidin-Producing Acrostalagmus luteoalbus, a Major Constituent of Mixed Mycobiota Contaminating Insulation Material in an Outdoor Wall

Occupants may complain about indoor air quality in closed spaces where the officially approved standard methods for indoor air quality risk assessment fail to reveal the cause of the problem. This study describes a rare genus not previously detected in Finnish buildings, Acrostalagmus, and its species A. luteoalbus as the major constituents of the mixed microbiota in the wet cork liner from an outdoor wall. Representatives of the genus were also present in the settled dust in offices where occupants suffered from symptoms related to the indoor air. One strain, POB8, was identified as A. luteoalbus by ITS sequencing. The strain produced the immunosuppressive and cytotoxic melinacidins II, III, and IV, as evidenced by mass spectrometry analysis. In addition, the classical toxigenic species indicating water damage, mycoparasitic Trichoderma, Aspergillus section Versicolores, Aspergillus section Circumdati, Aspergillus section Nigri, and Chaetomium spp., were detected in the wet outdoor wall and settled dust from the problematic rooms. The offices exhibited no visible signs of microbial growth, and the airborne load of microbial conidia was too low to explain the reported symptoms. In conclusion, we suggest the possible migration of microbial bioactive metabolites from the wet outdoor wall into indoor spaces as a plausible explanation for the reported complaints.

Natterin an aerolysin-like fish toxin drives IL-1β-dependent neutrophilic inflammation mediated by caspase-1 and caspase-11 activated by the inflammasome sensor NLRP6

Natterin is an aerolysin-like pore-forming toxin responsible for the toxic effects of the venom of the medically significant fish Thalassophryne nattereri. Using a combination of pharmacologic and genetic loss-of-function approaches we conduct a systematic investigation of the regulatory mechanisms that control Natterin-induced neutrophilic inflammation in the peritonitis model. Our data confirmed the capacity of Natterin to induce a strong and sustained neutrophilic inflammation leading to systemic inflammatory lung infiltration and revealed overlapping regulatory paths in its control. We found that Natterin induced the extracellular release of mature IL-1β and the sustained production of IL-33 by bronchial epithelial cells. We confirmed the dependence of both ST2/IL-33 and IL-17A/IL-17RA signaling on the local and systemic neutrophils migration, as well as the crucial role of IL-1α, caspase-1 and caspase-11 for neutrophilic inflammation. The inflammation triggered by Natterin was a gasdermin-D-dependent inflammasome process, despite the cells did not die by pyroptosis. Finally, neutrophilic inflammation was mediated by non-canonical NLRP6 and NLRC4 adaptors through ASC interaction, independent of NLRP3. Our data highlight that the inflammatory process dependent on non-canonical inflammasome activation can be a target for pharmacological intervention in accidents by T. nattereri, which does not have adequate specific therapy.

Understanding the role of Inflammasome in Angina Pectoris

Angina pectoris, associated with coronary artery disease, a cardiovascular disease where, pain is caused by adverse oxygen supply in myocardium, resulting in contractility and discomfort in chest. Inflammasomes, triggered by stimuli due to infection and cellular stress have identified to play a vital role in the progression of cardiovascular disorders and thus, causing various symptoms like angina pectoris. Nlrp3 inflammasome, a key contributor in the pathogenesis of angina pectoris, requires activation and primary signaling for the commencement of inflammation. Nlrp3 inflammasome elicit out an inflammatory response by emission of pro inflammatory cytokines by ROS (reactive oxygen species) production, mobilization of K+ efflux and Ca2+ and by activation of lysosome destabilization that eventually causes pyroptosis, a programmed cell death process. Thus, inflammasome are considered to be one of the factors involved in the progression of coronary artery diseases and have an intricate role in development of angina pectoris.

Bioreactivity, Guttation and Agents Influencing Surface Tension of Water Emitted by Actively Growing Indoor Mould Isolates

The secretion of metabolites in guttation droplets by indoor moulds is not well documented. This study demonstrates the guttation of metabolites by actively growing common indoor moulds. Old and fresh biomasses of indoor isolates of Aspergillus versicolor, Chaetomium globosum, Penicillium expansum, Trichoderma atroviride, T. trixiae, Rhizopus sp. and Stachybotrys sp. were compared. Metabolic activity indicated by viability staining and guttation of liquid droplets detected in young (<3 weeks old) biomass were absent in old (>6 months old) cultures consisting of dehydrated hyphae and dormant conidia. Fresh (<3 weeks old) biomasses were toxic more than 10 times towards mammalian cell lines (PK-15 and MNA) compared to the old dormant, dry biomasses, when calculated per biomass wet weight and per conidial particle. Surfactant activity was emitted in exudates from fresh biomass of T. atroviride, Rhizopus sp. and Stachybotrys sp. Surfactant activity was also provoked by fresh conidia from T. atroviride and Stachybotrys sp. strains. Water repealing substances were emitted by cultures of P. expansum, T. atroviride and C. globosum strains. The metabolic state of the indoor fungal growth may influence emission of liquid soluble bioreactive metabolites into the indoor air.

HIV-1 Envelope Overcomes NLRP3-Mediated Inhibition of F-Actin Polymerization for Viral Entry

Purinergic receptors and nucleotide-binding domain leucine-rich repeat containing (NLR) proteins have been shown to control viral infection. Here, we show that the NLR family member NLRP3 and the purinergic receptor P2Y2 constitutively interact and regulate susceptibility to HIV-1 infection. We found that NLRP3 acts as an inhibitory factor of viral entry that represses F-actin remodeling. The binding of the HIV-1 envelope to its host cell receptors (CD4, CXCR4, and/or CCR5) overcomes this restriction by stimulating P2Y2. Once activated, P2Y2 enhances its interaction with NLRP3 and stimulates the recruitment of the E3 ubiquitin ligase CBL to NLRP3, ultimately leading to NLRP3 degradation. NLRP3 degradation is permissive for PYK2 phosphorylation (PYK2Y402^∗) and subsequent F-actin polymerization, which is required for the entry of HIV-1 into host cells. Taken together, our results uncover a mechanism by which HIV-1 overcomes NLRP3 restriction that appears essential for the accomplishment of the early steps of HIV-1 entry.

BAFF-driven NLRP3 inflammasome activation in B cells

BAFF supports B-cell survival and homeostasis by activating the NF-κB pathway. While NF-κB is also involved in the priming signal of NLRP3 inflammasome, the role of BAFF in NLRP3 inflammasome regulation is unknown. Here we report BAFF engagement to BAFF receptor elicited both priming and activating signals for NLRP3 inflammasomes in primary B cells and B lymphoma cell lines. This induction of NLRP3 inflammasomes by BAFF led to increased NLRP3 and IL-1β expression, caspase-1 activation, IL-1β secretion, and pyroptosis. Mechanistically, BAFF activated NLRP3 inflammasomes by promoting the association of cIAP-TRAF2 with components of NLRP3 inflammasomes, and by inducing Src activity-dependent ROS production and potassium ion efflux. B-cell receptor (BCR) stimulation on the Lyn signaling pathway inhibited BAFF-induced Src activities and attenuated BAFF-induced NLRP3 inflammasome activation. These findings reveal an additional function of BAFF in B-cell homeostasis that is associated with BCR activities.

Inflammasomes: a preclinical assessment of targeting in atherosclerosis

INTRODUCTION

Inflammasomes are central to atherosclerotic vascular dysfunction with regulatory effects on inflammation, immune modulation, and lipid metabolism. The NLRP3 inflammasome is a critical catalyst for atherogenesis thus highlighting its importance in understanding the pathophysiology of atherosclerosis and for the identification of novel therapeutic targets and biomarkers for the treatment of cardiovascular disease.

AREAS COVERED

This review includes an overview of macrophage lipid metabolism and the role of NLRP3 inflammasome activity in cardiovascular inflammation and atherosclerosis. We highlight key activators, signal transducers and major regulatory components that are being considered as putative therapeutic targets for inhibition of NLRP3-mediated cardiovascular inflammation and atherosclerosis.

EXPERT OPINION

NLRP3 inflammasome activity lies at the nexus between inflammation and cholesterol metabolism; it offers unique opportunities for understanding atherosclerotic pathophysiology and identifying novel modes of treatment. As such, a host of NLRP3 signaling cascade components have been identified as putative targets for drug development. We catalog these current discoveries in therapeutic targeting of the NLRP3 inflammasome and, utilizing the CANTOS trial as the translational (bench-to-bedside) archetype, we examine the complexities, challenges, and ultimate goals facing the field of atherosclerosis research.

A Novel Link between Early Life Allergen Exposure and Neuroimmune Development in Children

Purpose

As COVID-19 unprecedented situation significantly increased the time families spend indoors, the awareness of unhealthy living conditions negatively impacting immune system and early neurodevelopment of children is of crucial importance.

Methods

We retrospectively reviewed unrelated cases of the children with confirmed multiple indoor allergen sensitization due to prolonged exposure to unhealthy indoor environment with infestation and water damage, who, in addition to multiple health problems related to allergy and asthma, also developed neuroimmune complications and growth delay.

Results

Documented early in life atypical neurologic and behavioral changes were common in all cases. Clinical analysis did not establish other causative reason aside from prenatal and early life exposure to unhealthy living conditions. Alternaria Alternara and Penicillium/Aspergillus molds were found in all homes and sensitization was confirmed in all cases. Significant similarities in the symptoms recorded in all three families led us to a hypothesis that, likely, a significant level of the immune response to external immunogenic pathological stimulus such as mold spore protein, mycotoxin protein, dust mite protein, decay-related volatile particles (VOC) skewed a balance of the neuroimmune interactions, and further affected neuronal network establishment. As all children exhibited significant spectrum of the systemic inflammatory conditions early in life, coupled with inability to follow normal neurodevelopment, we hypothesize that an overwhelming activation of the aggressive immune mechanisms by the epigenetic factors led to glia activation, cytokine storm and break of tolerance.

Conclusions

We hypothesize that developing immune system exhibited aggressive responses due to environmental danger signals, subsequently TH-1 or TH-2 switch enables multiple clinical syndromes development with atypical presentation due to the described novel mechanism. An increased due to the COVID-19 lock-down may increase an amount of exposure of vulnerable people to indoor biological particles and volatile organic compounds present in unhealthy buildings. It is of crucial importance to identify and remediate indoor exposure factors that can decrease immune protection, especially against infectious pathogens such as novel coronavirus.

Anti-Inflammatory Effects of Diospyrin on Lipopolysaccharide-Induced Inflammation Using RAW 264.7 Mouse Macrophages

Diospyrin is a bisnaphthoquinonoid medicinal compound derived from Diospyros lotus, with known anti-cancer, anti-tubercular, and anti-leishmanial activities against Leishmania donovani. However, the effects of diospyrin on lipopolysaccharide (LPS)-induced macrophage activation and inflammation are not fully reported. In this study, the anti-inflammatory effects of diospyrin on LPS-induced macrophages were examined. Diospyrin showed no toxicity in RAW 264.7 at concentrations of up to 10 μM. Diospyrin moderated the production of nitric oxide (NO), monocyte chemotactic protein-1, macrophage inflammatory protein-1β, interleukin (IL)-6, IL-10, granulocyte colony-stimulating factor, granulocyte macrophage colony-stimulating factor, vascular endothelial growth factor, leukemia inhibitory factor, and RANTES/CCL5, as well as calcium release in LPS-induced RAW 264.7, at concentrations of up to 10 μM significantly (p < 0.05). Diospyrin also significantly inhibited the phosphorylation of p38 mitogen-activated protein kinase (MAPK) and mRNA expression of C/EBP homologous protein (CHOP), as well as tumor necrosis factor receptor superfamily member 6 (Fas), in LPS-induced RAW 264.7 cells at concentrations of up to 10 μM (p < 0.05). Diospyrin exhibits anti-inflammatory properties mediated via inhibition of NO, and cytokines in LPS-induced mouse macrophages via the ER-stressed calcium-p38 MAPK/CHOP/Fas pathway.

Src-family kinase-Cbl axis negatively regulates NLRP3 inflammasome activation

Activation of the NLRP3 inflammasome is crucial for immune defense, but improper and excessive activation causes inflammatory diseases. We previously reported that Pyk2 is essential for NLRP3 inflammasome activation. Here we show that the Src-family kinases (SFKs)-Cbl axis plays a pivotal role in suppressing NLRP3 inflammasome activation in response to stimulation by nigericin or ATP, as assessed using gene knockout and gene knockdown cells, dominant active/negative mutants, and pharmacological inhibition. We reveal that the phosphorylation of Cbl is regulated by SFKs, and that phosphorylation of Cbl at Tyr371 suppresses NLRP3 inflammasome activation. Mechanistically, Cbl decreases the level of phosphorylated Pyk2 (p-Pyk2) through ubiquitination-mediated proteasomal degradation and reduces mitochondrial ROS (mtROS) production by contributing to the maintenance of mitochondrial size. The lower levels of p-Pyk2 and mtROS dampen NLRP3 inflammasome activation. In vivo, inhibition of Cbl with an analgesic drug, hydrocotarnine, increases inflammasome-mediated IL-18 secretion in the colon, and protects mice from dextran sulphate sodium-induced colitis. Together, our novel findings provide new insights into the role of the SFK-Cbl axis in suppressing NLRP3 inflammasome activation and identify a novel clinical utility of hydrocortanine for disease treatment.

Review article: Role of satiety hormones in anorexia induction by Trichothecene mycotoxins

The trichothecenes, produced by Fusarium, contaminate animal feed and human food in all stages of production and lead to a large spectrum of adverse effects for animal and human health. An hallmark of trichothecenes toxicity is the onset of emesis followed by anorexia and food intake reduction in different animal species (mink, mice and pig). The modulation of emesis and anorexia can result from a direct action of trichothecenes in the brain or from an indirect action in the gastrointestinal tract. The direct action of trichothecenes involved specific brain areas such as nucleate tractus solitarius in the brainstem and the arcuate nuclei in the hypothalamus. Activation of these areas in the brain leads to the activation of specific neuronal populations containing anorexigenic factors (POMC and CART). The indirect action of trichothecenes in the gastrointestinal tract involved, by enteroendocrine cells, the secretion of several gut hormones such as cholecystokinin (CCK) and peptide YY (PYY) but also glucagon-like peptide 1 (GLP-1), gastric inhibitory peptide (GIP) and 5-hydroxytryptamine (5-HT), which transmitted signals to the brain via the gut-brain axis. This review summarizes current knowledge on the effects of trichothecenes, especially deoxynivalenol, on emesis and anorexia and discusses the mechanisms underlying trichothecenes-induced food reduction.

NLRP3: A Novel Mediator in Cardiovascular Disease

Cardiovascular disease is a major cause of death worldwide. Inflammasome infiltration has been identified to play a central role in the pathological progression of certain cardiovascular diseases, such as vascular damage spanning atherosclerosis, aneurysm, or arteritis; ischemic heart disease; and other nonischemic heart diseases including diabetic cardiomyopathy, chronic heart failure, and hypertension- or virus-induced cardiac dysfunction. The NLRP3 inflammasome, a key participant in the innate immune response, requires both priming and activation signals for the initiation of inflammation. Piling evidence has revealed that the NLRP3 inflammasome could exert an inflammatory effect by inducing the secretion of proinflammatory cytokines (i.e., IL-1β, IL-18) or could cause pyroptosis, a novel programmed cell death process, in a caspase-1-dependent manner. The importance of the NLRP3 inflammasome in cardiac disease has been broadly investigated. In this review, we present the current knowledge regarding the function of NLRP in vascular disease, ischemic heart disease, and nonischemic heart disease and discuss the potential therapeutic options targeting the NLRP3 inflammasome.

Recent Advances in the Molecular Mechanisms Underlying Pyroptosis in Sepsis

Sepsis is recognized as a life-threatening organ dysfunctional disease that is caused by dysregulated host responses to infection. Up to now, sepsis still remains a dominant cause of multiple organ dysfunction syndrome (MODS) and death among severe condition patients. Pyroptosis, originally named after the Greek words “pyro” and “ptosis” in 2001, has been defined as a specific programmed cell death characterized by release of inflammatory cytokines. During sepsis, pyroptosis is required for defense against bacterial infection because appropriate pyroptosis can minimize tissue damage. Even so, pyroptosis when overactivated can result in septic shock, MODS, or increased risk of secondary infection. Proteolytic cleavage of gasdermin D (GSDMD) by caspase-1, caspase-4, caspase-5, and caspase-11 is an essential step for the execution of pyroptosis in activated innate immune cells and endothelial cells stimulated by cytosolic lipopolysaccharide (LPS). Cleaved GSDMD also triggers NACHT, LRR, and PYD domain-containing protein (NLRP) 3-mediated activation of caspase-1 via an intrinsic pathway, while the precise mechanism underlying GSDMD-induced NLRP 3 activation remains unclear. Hence, this study provides an overview of the recent advances in the molecular mechanisms underlying pyroptosis in sepsis.

Impaired Na+-K+-ATPase signaling in renal proximal tubule contributes to hyperuricemia-induced renal tubular injury

Hyperuricemia contributes to renal inflammation. We aimed to investigate the role of Na⁺–K⁺–ATPase (NKA) in hyperuricemia-induced renal tubular injury. Human primary proximal tubular epithelial cells (PTECs) were incubated with uric acid (UA) at increasing doses or for increasing lengths of time. PTECs were then stimulated by pre-incubation with an NKA α1 expression vector or small interfering RNA before UA (100 μg ml⁻¹, 48 h) stimulation. Hyperuricemic rats were induced by gastric oxonic acid and treated with febuxostat (Feb). ATP levels, the activity of NKA and expression of its α1 subunit, Src, NOD-like receptor pyrin domain-containing protein 3 (NLRP3) and interleukin 1β (IL-1β) were measured both in vitro and in vivo. Beginning at concentrations of 100 μg ml⁻¹, UA started to dose-dependently reduce NKA activity. UA at a concentration of 100 μg ml⁻¹ time-dependently affected the NKA activity, with the maximal increased NKA activity at 24 h, but the activity started to decrease after 48 h. This inhibitory effect of UA on NKA activity at 48 h was in addition to a decrease in NKA α1 expression in the cell membrane, but an increase in lysosomes. This process also involved the subsequent activation of Src kinase and NLRP3, promoting IL-1β processing. In hyperuricemic rats, renal cortex NKA activity and its α1 expression were upregulated at the 7th week and both decreased at the 10th week, accompanied with increased renal cortex expression of Src, NLRP3 and IL-1β. The UA levels were reduced and renal tubular injuries in hyperuricemic rats were alleviated in the Feb group. Our data suggested that the impairment of NKA and its consequent regulation of Src, NLRP3 and IL-1β in the renal proximal tubule contributed to hyperuricemia-induced renal tubular injury.

Effects of Src Kinase Inhibition on Expression of Protein Tyrosine Phosphatase 1B after Brain Hypoxia in a Piglet Animal Model

Background

Protein tyrosine phosphatases (PTPs) in conjunction with protein tyrosine kinases (PTKs) regulate cellular processes by posttranslational modifications of signal transduction proteins. PTP nonreceptor type 1B (PTP-1B) is an enzyme of the PTP family. We have previously shown that hypoxia induces an increase in activation of a class of nonreceptor PTK, the Src kinases. In the present study, we investigated the changes that occur in the expression of PTP-1B in the cytosolic component of the brain of newborn piglets acutely after hypoxia as well as long term for up to 2 weeks.

Methods

Newborn piglets were divided into groups: normoxia, hypoxia, hypoxia followed by 1 day and 15 days in FiO₂ 0.21, and hypoxia pretreated with Src kinase inhibitor PP2, prior to hypoxia followed by 1 day and 15 days. Hypoxia was achieved by providing 7% FiO₂ for 1 hour and PTP-1B expression was measured via immunoblotting.

Results

PTP-1B increased posthypoxia by about 30% and persisted for 2 weeks while Src kinase inhibition attenuated the expected PTP-1B-increased expression.

Conclusions

Our study suggests that Src kinase mediates a hypoxia-induced increased PTP-1B expression.

Synergistic proinflammatory interactions of microbial toxins and structural components characteristic to moisture-damaged buildings

Indoor exposure to microbes and their structural and metabolic compounds is notoriously complex. To study proinflammatory interactions between the multiple microbial agents, macrophages derived from human THP-1 monocytic cells were exposed to several concentrations of microbial toxins alone (emodin, enniatin B, physcion, sterigmatocystin, valinomycin) and in combination with microbial structural components (bacterial lipopolysaccharide [LPS] or fungal β-glucan). While the expression of proinflammatory cytokines TNFα and IL-1β to single toxins alone was modest, low-dose co-exposure with structural components increased the responses of emodin, enniatin B, and valinomycin synergistically, both at the mRNA and protein level, as measured by RT-qPCR and ELISA, respectively. Co-exposure of toxins and β-glucan resulted in consistent synergistically increased expression of several inflammation-related genes, while some of the responses with LPS were also inhibitory. Co-exposure of toxins with either β-glucan or LPS induced also mitochondrial damage and autophagocytosis. The results demonstrate that microbial toxins together with bacterial and fungal structural components characteristic to moisture-damaged buildings can have drastic synergistic proinflammatory interactions at low exposure levels.

Lung inflammation caused by inhaled toxicants: a review

Exposure of the lungs to airborne toxicants from different sources in the environment may lead to acute and chronic pulmonary or even systemic inflammation. Cigarette smoke is the leading cause of chronic obstructive pulmonary disease, although wood smoke in urban areas of underdeveloped countries is now recognized as a leading cause of respiratory disease. Mycotoxins from fungal spores pose an occupational risk for respiratory illness and also present a health hazard to those living in damp buildings. Microscopic airborne particulates of asbestos and silica (from building materials) and those of heavy metals (from paint) are additional sources of indoor air pollution that contributes to respiratory illness and is known to cause respiratory illness in experimental animals. Ricin in aerosolized form is a potential bioweapon that is extremely toxic yet relatively easy to produce. Although the aforementioned agents belong to different classes of toxic chemicals, their pathogenicity is similar. They induce the recruitment and activation of macrophages, activation of mitogen-activated protein kinases, inhibition of protein synthesis, and production of interleukin-1 beta. Targeting either macrophages (using nanoparticles) or the production of interleukin-1 beta (using inhibitors against protein kinases, NOD-like receptor protein-3, or P2X7) may potentially be employed to treat these types of lung inflammation without affecting the natural immune response to bacterial infections.

Do inflammatory pathways drive melanomagenesis?

Inflammatory pathways serve to protect the host and promote tissue healing/repair; however, over-activation or dysregulation can be pathological with unintended consequences including malignant progression. A correlation between inflammation and cancer has been well established, and anti-inflammatory medications have been shown to be chemopreventive in certain malignancies. Data are now becoming available that outline an inflammatory pathway that may have a critical role in melanomagenesis. ATP-regulated membrane channels/receptors P2X7 and PANX1 have been directly implicated in melanoma tumor growth. Among other potential effects, opening of the P2X7/PANX1 channel results in activation of the NALP3 inflammasome, which in turn leads to caspase-1 activation and increased levels of activated IL-1β. Elevated levels of caspase-1 and IL-1β have been correlated with melanoma progression, and inhibitors of the inflammasome, caspase and IL-1β activity have all been shown to inhibit melanoma growth. Among many other potential actions, IL-1β increases cyclooxygenase-2 expression leading to local increases in inflammatory mediators such as prostaglandin E2 (PGE2). Anti-inflammatory medications targeting the end of this pathway have had positive results for certain cancers but overall remain mixed for melanoma. A better understanding of the pathways and appropriate intervention points may help direct future therapies. In this viewpoint, we will review data and attempt to model an inflammatory pathway that may be critical for melanomagenesis and propose future directions for exploration.

Proteomic changes of alveolar lining fluid in illnesses associated with exposure to inhaled non-infectious microbial particles

Background

Hyperresponsiveness to inhaled non-infectious microbial particles (NIMPs) has been associated with illnesses in the airways. Hypersensitivity pneumonitis (HP) is considered to be the prototype for these NIMPs-related diseases; however, there is no consensus on the definitions or diagnostic criteria for HP and the spectrum of related illnesses.

Methods and Findings

In order to identify the possible diagnostic markers for illnesses associated with NIMPs in alveolar lining fluid, we performed a proteomic analysis using a two-dimensional difference gel electrophoresis on bronchoalveolar lavage (BAL) fluid from patients with exposure to NIMPs in the context of damp building-related illness (DBRI) or conditions on the borderline to acute HP, designated here as agricultural type of microbial exposure (AME). Samples from patients with HP and sarcoidosis (SARC) were included for reference. Results were compared to results of healthy subjects (CTR). Western blot was used for validation of potential marker proteins from BAL fluid and plasma. Protein expression patterns suggest a close similarity between AME and HP, while DBRI was similar to CTR. However, in DBRI the levels of the inflammation associated molecules galectin-3 and alpha-1-antitrypsin were increased. A novel finding emerging from this study was the increases of semenogelin levels in BAL fluid from patients with AME, HP and SARC. Histone 4 levels were increased in AME, HP and SARC. Elevated plasma levels of histone 2B were detected in HP and SARC, suggesting it to be a potential blood indicator for inflammatory diseases of the lungs.

Conclusions

In this study, the proteomic changes in bronchoalveolar lavage of DBRI patients were distinct from other NIMP exposure associated lung diseases, while changes in AME overlapped those observed for HP patient samples. Some of the proteins identified in this study, semenogelin and histone 4, could function as diagnostic markers for differential diagnosis between DBRI and HP-like conditions.