G protein-coupled receptors in the neuropathophysiology of asthma

Asthma is a complex genetic disorder with environmental influences and is characterized by airway inflammation, reversible airflow obstruction, and airway hyperresponsiveness (AHR). The arachidonic acid metabolite thromboxane A2 (TXA2), is a potent lipid mediator released by platelets and inflammatory cells and is capable of inducing bronchoconstriction. In the airways, it has been postulated that TXA2 causes airway constriction by direct activation of TP receptors on airway smooth muscle (ASM) cells. Here we demonstrate that although TXA2 can mediate a dramatic increase in ASM constriction, this response is largely dependent on vagal innervation of the airways and is highly sensitive to muscarinic acetylcholine receptor (mAChR) antagonists. Further analyses demonstrate that TP-dependent ASM constriction requires M3 mAChR expression. To further define the mechanism underlying TXA2 meditated airway constriction, mice carrying a Tp receptor locus that is sensitive to disruption by cre recombinase were generated. These mice were crossed with nestin-cre transgenic mice, which express cre recombinase throughout the nervous systems. Here we demonstrate that loss of the TP receptor throughout the nervous system does not significantly affect TXA2 airway reactivity. To assess ASM TP receptor function, we crossed the floxed Tp receptor mice with SM22-cre transgenic mice, which express cre recombinase in smooth muscle. The resultant smooth muscle TP receptor deficient animals demonstrate attenuated airway responses following aerosol challenges with TXA2. Together, these findings suggest that TXA2 mediates airway reactivity and AHR through collaborations between ASM Tp receptors and the M3 mAChR. In addition to TXA2, we also evaluated the role of NPSR1 (GPRA), a newly deorphanized G protein-coupled receptor that has been shown to be a promising candidate gene associated with asthma in human populations. We report here that the change in airway resistance in response to methacholine was identical in control and NPSR1 deficient mice and the development of allergic lung disease in NPSR1 deficient mice is unaltered. In contrast to previously published data, our analyses also failed to detect expression of NPSR1 in human lung tissue or in mice with allergic lung disease. Taken together, our studies fail to support a direct contribution of NPSR1 to asthma pathogenesis

An orphaned Mce-associated membrane protein of M ycobacterium tuberculosis is a virulence factor that stabilizes Mce transporters: OmamA functions in virulence and Mce stability

Mycobacterium tuberculosis proteins that are exported out of the bacterial cytoplasm are ideally positioned to be virulence factors; however, the functions of individual exported proteins remain largely unknown. Previous studies identified Rv0199 as an exported membrane protein of unknown function. Here, we characterized the role of Rv0199 in M. tuberculosis virulence using an aerosol model of murine infection. Rv0199 appears to be a member of a Mce-associated membrane (Mam) protein family leading us to rename it OmamA, for orphaned Mce-associated membrane protein A. Consistent with a role in Mce transport, we showed OmamA is required for cholesterol import, which is a Mce4-dependent process. We further demonstrated a function for OmamA in stabilizing protein components of the Mce1 transporter complex. These results indicate a function of OmamA in multiple Mce transporters and one that may be analogous to the role of VirB8 in stabilizing Type IV secretion systems, as structural similarities between Mam proteins and VirB8 proteins are predicted by the Phyre 2 program. In this study, we provide functional information about OmamA and shed light on the function of Mam family proteins in Mce transporters

Deletion of ripA Alleviates Suppression of the Inflammasome and MAPK by Francisella tularensis

Francisella tularensis is a facultative intracellular pathogen and potential biothreat agent. Evasion of the immune response contributes to the extraordinary virulence of this organism although the mechanism is unclear. Whereas wild-type strains induced low levels of cytokines, an F. tularensis ripA deletion mutant (LVSΔripA) provoked significant release of IL-1β, IL-18, and TNF-α by resting macrophages. IL-1β and IL-18 secretion was dependent on inflammasome components pyrin-caspase recruitment domain/apoptotic speck-containing protein with a caspase recruitment domain and caspase-1, and the TLR/IL-1R signaling molecule MyD88 was required for inflammatory cytokine synthesis. Complementation of LVSΔripA with a plasmid encoding ripA restored immune evasion. Similar findings were observed in a human monocytic line. The presence of ripA nearly eliminated activation of MAPKs including ERK1/2, JNK, and p38, and pharmacologic inhibitors of these three MAPKs reduced cytokine induction by LVSΔripA. Animals infected with LVSΔripA mounted a stronger IL-1β and TNF-α response than that of mice infected with wild-type live vaccine strain. This analysis revealed novel immune evasive mechanisms of F. tularensis

Aggravation of allergic airway inflammation by cigarette smoke in mice is CD44-dependent

Background : Although epidemiological studies reveal that cigarette smoke (CS) facilitates the development and exacerbation of allergic asthma, these studies offer limited information on the mechanisms involved. The transmembrane glycoprotein CD44 is involved in cell adhesion and acts as a receptor for hyaluronic acid and osteopontin. We aimed to investigate the role of CD44 in a murine model of CS-facilitated allergic airway inflammation. Methods : Wild type (WT) and CD44 knock-out (KO) mice were exposed simultaneously to house dust mite (HDM) extract and CS. Inflammatory cells, hyaluronic acid (HA) and osteopontin (OPN) levels were measured in bronchoalveolar lavage fluid (BALF). Proinflammatory mediators, goblet cell metaplasia and peribronchial eosinophilia were assessed in lung tissue. T-helper (Th) 1, Th2 and Th17 cytokine production was evaluated in mediastinal lymph node cultures. Results : In WT mice, combined HDM/CS exposure increased the number of inflammatory cells and the levels of HA and OPN in BALF and Th2 cytokine production in mediastinal lymph nodes compared to control groups exposed to phosphate buffered saline (PBS)/CS, HDM/Air or PBS/Air. Furthermore, HDM/CS exposure significantly increased goblet cell metaplasia, peribronchial eosinophilia and inflammatory mediators in the lung. CD44 KO mice exposed to HDM/CS had significantly fewer inflammatory cells in BALF, an attenuated Th2 cytokine production, as well as decreased goblet cells and peribronchial eosinophils compared to WT mice. In contrast, the levels of inflammatory mediators were similar or higher than in WT mice. Conclusion : We demonstrate for the first time that the aggravation of pulmonary inflammation upon combined exposure to allergen and an environmental pollutant is CD44-dependent. Data from this murine model of concomitant exposure to CS and HDM might be of importance for smoking allergic asthmatics

Dimethyl fumarate in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial

Dimethyl fumarate (DMF) inhibits inflammasome-mediated inflammation and has been proposed as a treatment for patients hospitalised with COVID-19. This randomised, controlled, open-label platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), is assessing multiple treatments in patients hospitalised for COVID-19 (NCT04381936, ISRCTN50189673). In this assessment of DMF performed at 27 UK hospitals, adults were randomly allocated (1:1) to either usual standard of care alone or usual standard of care plus DMF. The primary outcome was clinical status on day 5 measured on a seven-point ordinal scale. Secondary outcomes were time to sustained improvement in clinical status, time to discharge, day 5 peripheral blood oxygenation, day 5 C-reactive protein, and improvement in day 10 clinical status. Between 2 March 2021 and 18 November 2021, 713 patients were enroled in the DMF evaluation, of whom 356 were randomly allocated to receive usual care plus DMF, and 357 to usual care alone. 95% of patients received corticosteroids as part of routine care. There was no evidence of a beneficial effect of DMF on clinical status at day 5 (common odds ratio of unfavourable outcome 1.12; 95% CI 0.86-1.47; p = 0.40). There was no significant effect of DMF on any secondary outcome

Dimethyl fumarate in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial

Dimethyl fumarate (DMF) inhibits inflammasome-mediated inflammation and has been proposed as a treatment for patients hospitalised with COVID-19. This randomised, controlled, open-label platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), is assessing multiple treatments in patients hospitalised for COVID-19 (NCT04381936, ISRCTN50189673). In this assessment of DMF performed at 27 UK hospitals, adults were randomly allocated (1:1) to either usual standard of care alone or usual standard of care plus DMF. The primary outcome was clinical status on day 5 measured on a seven-point ordinal scale. Secondary outcomes were time to sustained improvement in clinical status, time to discharge, day 5 peripheral blood oxygenation, day 5 C-reactive protein, and improvement in day 10 clinical status. Between 2 March 2021 and 18 November 2021, 713 patients were enroled in the DMF evaluation, of whom 356 were randomly allocated to receive usual care plus DMF, and 357 to usual care alone. 95% of patients received corticosteroids as part of routine care. There was no evidence of a beneficial effect of DMF on clinical status at day 5 (common odds ratio of unfavourable outcome 1.12; 95% CI 0.86-1.47; p = 0.40). There was no significant effect of DMF on any secondary outcome

Non-inflammasome forming NLRs in inflammation and tumorigenesis

Aberrant inflammation is an enabling characteristic of tumorigenesis. Thus, signaling cascades that alter inflammatory activation and resolution are of specific relevance to disease pathogenesis. Pattern recognition receptors (PRRs) are essential mediators of the host immune response and have emerged as critical elements affecting multiple facets of tumor pathobiology. The nucleotide-binding domain and leucine-rich repeat containing (NLR) proteins are intracellular PRRs that sense microbial and non-microbial products. Members of the NLR family can be divided into functional subgroups based on their ability to either positively or negatively regulate the host immune response. Recent studies have identified a novel subgroup of non-inflammasome forming NLRs that negatively regulate diverse biological pathways associated with both inflammation and tumorigenesis. Understanding the mechanisms underlying the function of these unique NLRs will assist in the rationale design of future therapeutic strategies targeting a wide spectrum of inflammatory diseases and cancer. Here, we will discuss recent findings associated with this novel NLR subgroup and mechanisms by which these PRRs may function to alter cancer pathogenesis

Beyond the inflammasome: regulatory NOD-like receptor modulation of the host immune response following virus exposure

Široko je prihvaćeni koncept da žučovod povećava promjer nakon kolecistektomije. Međutim, postoje prijeporni rezultati u dostupnoj literaturi o ovoj temi. Saznanje može li se kod kolecistektomiranih pacijenata očekivati širi promjer žučnih vodova od opće populacije bilo bi korisno da se izbjegnu nepotrebna i potencijalno invazivna istraživanja žučnih vodova. Cilj rada je prikazati radiološke tehnike u analizi žučnog mjehura i žučnih vodova i prikazati radiološke tehnike u analizi promjena promjera žučnih vodova nakon kolecistektomije. Istražiti relevantnu literaturu i znanstvene baze podataka s prikazom radova na temu dosadašnjih istraživanja promjena promjera žučnih vodova nakon kolecistektomije. Radiološke tehnike u analizi promjena promjera žučnih vodova nakon kolecistektomije su ultrazvuk, endoskopska retrogradna kolangiopankreatografija, endoskopski ultrazvuk, kompjuterizirana tomografija, magnetska rezonancija s magnetskorezonantnom kolangiopankreatografijom. Većina studija na temu promjena promjera žučnih vodova nakon kolecistektomije je ultrazvučna, što je i razumljivo zbog široke dostupnosti i neinvazivnosti pretrage. Veliki broj ultrazvučnih studija su potvrdile ali i opovrgnule tezu o postkolecistektomičnoj dilataciji žučovoda. Prijeporni rezultati mogu se tumačiti i niskom osjetljivošću ultrazvuka u odnosu na druge radiološke tehnike kao što su EUS, MRCP i ERCP. U studijama CT-om koji također ima nisku osjetljivost također su vidljivi prijeporni rezultati. Najmanji broj studija izveden je tehnikama koje imaju veliku osjetljivost, ERCP-om zbog invazivnosti pretrage te EUS-om i MRCP-om zbog manje dostupnosti i cijene pretrage., Rezultati tih studija govore u prilog postkolecistektomične dilatacije. Potrebna su daljnja istraživanja s viskom metodološkom kvalitetom za potvrdu postkolecistektomične dilatacije žučovoda.It is widely accepted that the common bile duct diameter increases after cholecystectomy. However, there are controversial results in available literature on this subject. Knowledge whether cholecystectomy patients are expected to have a wider diameter of bile ducts than the general population would be beneficial to prevent unnecessary and potentially invasive research of the bile ducts. The aim of the research is to present radiological techniques in the analysis of the gallbladder and bile duct and the analysis of bile duct diameter changes after cholecystectomy. Relevant literature and scientific databases on the topic and current research is presented. Radiological techniques in the analysis of the common bile duct diameter after cholecystectomy are: ultrasound, endoscopic retrograde cholangiopankreatography, endoscopic ultrasound, computerized tomography, magnetic resonance imaging with magnetic resonance cholangiopankreatography. Most of the studies of the common bile duct diameter changes after cholecystectomy are performed with ultrasound, due to the wide availability, reproducibily and non-invasiveness of the examination. A large number of ultrasound studies have confirmed but also rejected the thesis on postcholecistectomic dilation of the common bile duct. Controversial results can be interpreted with low sensitivity of ultrasound examination compared to other radiological techniques such as EUS, MRCP and ERCP. Controversial results are also reported for the CT studies. The smallest number of studies have been conducted with high sensitivity techniques. ERCP is a highly invasive examination and EUS and MRCP are not as available due to the high cost. Further research with high methodological quality is required to confirm the postcholecystectomic dilation of the bile ducts