CXCL4 synergizes with TLR8 for TBK1-IRF5 activation, epigenomic remodeling and inflammatory response in human monocytes

Regulation of endosomal Toll-like receptor (TLR) responses by the chemokine CXCL4 is implicated in inflammatory and fibrotic diseases, with CXCL4 proposed to potentiate TLR responses by binding to nucleic acid TLR ligands and facilitating their endosomal delivery. Here we report that in human monocytes/macrophages, CXCL4 initiates signaling cascades and downstream epigenomic reprogramming that change the profile of the TLR8 response by selectively amplifying inflammatory gene transcription and interleukin (IL)-1β production, while partially attenuating the interferon response. Mechanistically, costimulation by CXCL4 and TLR8 synergistically activates TBK1 and IKKε, repurposes these kinases towards an inflammatory response via coupling with IRF5, and activates the NLRP3 inflammasome. CXCL4 signaling, in a cooperative and synergistic manner with TLR8, induces chromatin remodeling and activates de novo enhancers associated with inflammatory genes. Our findings thus identify new regulatory mechanisms of TLR responses relevant for cytokine storm, and suggest targeting the TBK1-IKKε-IRF5 axis may be beneficial in inflammatory diseases.

Costimulation of TLR8 responses by CXCL4 in Human Monocytes Mediated by TBK1-IRF5 Signaling and Epigenomic Remodeling

CXCL4 regulates responses of immune cells to endosomal TLRs and has been implicated in the pathogenesis of inflammatory and fibrotic diseases. However, mechanisms by which CXCL4 modulates TLR responses, and its functions in monocytes/macrophages, are still unclear. Here we report that CXCL4 changes the profile of the TLR8 response in human monocytes by selectively and dramatically amplifying inflammatory gene transcription and IL-1b production while partially attenuating the IFN response. Mechanistically, costimulation by CXCL4 and TLR8 synergistically activated TBK1/IKKe and repurposed these kinases towards an inflammatory response via coupling with IRF5, and by activating the NLRP3 inflammasome without the need for a second signal. CXCL4 strongly induced chromatin remodeling in a cooperative and synergistic manner with TLR8 signaling, inducing de novo enhancers associated with inflammatory genes. These findings identify signaling and epigenomic mechanisms that underly synergistic activation of inflammatory genes by CXCL4 and TLR8, provide a new paradigm for modulation of TLR responses that is relevant for cytokine storm, and suggest targeting the TBK1/IKKe-IRF5 axis may be beneficial in inflammatory diseases.

A systems biology approach reveals new endoplasmic reticulum-associated targets for the correction of the ATP7B mutant causing Wilson disease

Copper (Cu) is an important trace element required for the activity of essential enzymes. However, excess Cu compromises the redox balance in cells and tissues causing serious toxicity. The process of disposal of excess Cu from organisms relies on the activity of Cu-transporting ATPase ATP7B. ATP7B is mainly expressed in liver hepatocytes where it sequesters the potentially toxic metal and mediates its excretion into the bile. Mutations in the ATP7B gene cause Wilson disease (WD), which is characterized by the accumulation of toxic Cu in the liver due to the scarce expression of ATP7B as well as the failure of ATP7B mutants to pump Cu and/or traffic to the Cu-excretion sites. The most frequent ATP7B mutant, H1069Q, still presents a significant Cu-transporting activity, but undergoes retention within the endoplasmic reticulum (ER) where the mutant is rapidly degraded. Expression of this ATP7B mutant has been recently reported to activate the p38 and JNK stress kinase pathways, which, in turn, trigger quality control mechanisms leading to the arrest of ATP7B-H1069Q in the ER and to the acceleration of its degradation. However, the main molecular players operating in these p38/JNK-dependent ER quality control pathways remain to be discovered. By using a combination of RNAseq, bioinformatics and RNAi approaches, we found a cluster of ER quality control genes whose expression is controlled by p38 and JNK and is required for the efficient retention of the ATP7B-H1069Q mutant in the ER. Silencing these genes reduced the accumulation of the ATP7B mutant in the ER and facilitated the mutant sorting and export to the Golgi and post-Golgi copper excretion sites. In sum, our findings reveal the ER-associated genes that could be utilized for the correction of ATP7B mutants and, hence, for the normalization of Cu homeostasis in Wilson disease.

Uroplakin traffic through the Golgi apparatus induces its fragmentation: new insights from novel in vitro models

Uroplakins (UPs) play an essential role in maintaining an effective urothelial permeability barrier at the level of superficial urothelial cell (UC) layer. Although the organization of UPs in the apical plasma membrane (PM) of UCs is well known, their transport in UCs is only partially understood. Here, we dissected trafficking of UPs and its differentiation-dependent impact on Golgi apparatus (GA) architecture. We demonstrated that individual subunits UPIb and UPIIIa are capable of trafficking from the endoplasmic reticulum to the GA in UCs. Moreover, UPIb, UPIIIa or UPIb/UPIIIa expressing UCs revealed fragmentation and peripheral redistribution of Golgi-units. Notably, expression of UPIb or UPIb/UPIIIa triggered similar GA fragmentation in MDCK and HeLa cells that do not express UPs endogenously. The colocalization analysis of UPIb/UPIIIa-EGFP and COPI, COPII or clathrin suggested that UPs follow constitutively the post-Golgi route to the apical PM. Depolymerisation of microtubules leads to complete blockade of the UPIb/UPIIIa-EGFP post-Golgi transport, while disassembly of actin filaments shows significantly reduced delivery of UPIb/UPIIIa-EGFP to the PM. Our findings show the significant effect of the UPs expression on the GA fragmentation, which enables secretory Golgi-outpost to be distributed as close as possible to the sites of cargo delivery at the PM.

The Menkes and Wilson disease genes counteract in copper toxicosis in Labrador retrievers: a new canine model for copper-metabolism disorders

The deleterious effects of a disrupted copper metabolism are illustrated by hereditary diseases caused by mutations in the genes coding for the copper transporters ATP7A and ATP7B. Menkes disease, involving ATP7A, is a fatal neurodegenerative disorder of copper deficiency. Mutations in ATP7B lead to Wilson disease, which is characterized by a predominantly hepatic copper accumulation. The low incidence and the phenotypic variability of human copper toxicosis hamper identification of causal genes or modifier genes involved in the disease pathogenesis. The Labrador retriever was recently characterized as a new canine model for copper toxicosis. Purebred dogs have reduced genetic variability, which facilitates identification of genes involved in complex heritable traits that might influence phenotype in both humans and dogs. We performed a genome-wide association study in 235 Labrador retrievers and identified two chromosome regions containing ATP7A and ATP7B that were associated with variation in hepatic copper levels. DNA sequence analysis identified missense mutations in each gene. The amino acid substitution ATP7B:p.Arg1453Gln was associated with copper accumulation, whereas the amino acid substitution ATP7A:p.Thr327Ile partly protected against copper accumulation. Confocal microscopy indicated that aberrant copper metabolism upon expression of the ATP7B variant occurred because of mis-localization of the protein in the endoplasmic reticulum. Dermal fibroblasts derived from ATP7A:p.Thr327Ile dogs showed copper accumulation and delayed excretion. We identified the Labrador retriever as the first natural, non-rodent model for ATP7B-associated copper toxicosis. Attenuation of copper accumulation by the ATP7A mutation sheds an interesting light on the interplay of copper transporters in body copper homeostasis and warrants a thorough investigation of ATP7A as a modifier gene in copper-metabolism disorders. The identification of two new functional variants in ATP7A and ATP7B contributes to the biological understanding of protein function, with relevance for future development of therapy.

Summary: Labrador retrievers with hereditary copper toxicosis are a useful new model for copper-metabolism disorders.

212D Visual Servoing with Respect to Planar Contours having Complex and Unknown Shapes

In this paper we present a complete system for segmenting, matching, tracking, and visual servoing with respect to unknown planar contours. Our system can be used with arbitrary contours of any shape and without any prior knowledge of their models. The system is first shown the target view. A selected contour is automatically extracted and its image shape is stored. The robot and object are then moved and the system automatically identifies the target. The matching step is performed together with the estimation of the homography matrix between the two views of the contour. Then, a 2½ D visual servoing technique is used to reposition the end-effector of a robot at the reference position relative to the planar contour. The system has been successfully tested on several contours with very complex shapes such as leaves, keys, and coastal outlines of islands. Experiments using a ship mock-up without any artificial marker proves that the system can be applied to the ship-building industry.

Identification of p38 MAPK and JNK as new targets for correction of Wilson disease-causing ATP7B mutants

Wilson disease (WD) is an autosomal recessive disorder that is caused by the toxic accumulation of copper (Cu) in the liver. The ATP7B gene, which is mutated in WD, encodes a multitransmembrane domain adenosine triphosphatase that traffics from the trans-Golgi network to the canalicular area of hepatocytes, where it facilitates excretion of excess Cu into the bile. Several ATP7B mutations, including H1069Q and R778L that are two of the most frequent variants, result in protein products, which, although still functional, remain in the endoplasmic reticulum. Thus, they fail to reach Cu excretion sites, resulting in the toxic buildup of Cu in the liver of WD patients. Therefore, correcting the location of these mutants by leading them to the appropriate functional sites in the cell should restore Cu excretion and would be beneficial to help large cohorts of WD patients. However, molecular targets for correction of endoplasmic reticulum-retained ATP7B mutants remain elusive. Here, we show that expression of the most frequent ATP7B mutant, H1069Q, activates p38 and c-Jun N-terminal kinase signaling pathways, which favor the rapid degradation of the mutant. Suppression of these pathways with RNA interference or specific chemical inhibitors results in the substantial rescue of ATP7B(H1069Q) (as well as that of several other WD-causing mutants) from the endoplasmic reticulum to the trans-Golgi network compartment, in recovery of its Cu-dependent trafficking, and in reduction of intracellular Cu levels.

CONCLUSION

Our findings indicate p38 and c-Jun N-terminal kinase as intriguing targets for correction of WD-causing mutants and, hence, as potential candidates, which could be evaluated for the development of novel therapeutic strategies to combat WD. (Hepatology 2016;63:1842-1859).

Wilson disease protein ATP7B utilizes lysosomal exocytosis to maintain copper homeostasis

Copper is an essential yet toxic metal and its overload causes Wilson disease, a disorder due to mutations in copper transporter ATP7B. To remove excess copper into the bile, ATP7B traffics toward canalicular area of hepatocytes. However, the trafficking mechanisms of ATP7B remain elusive. Here, we show that, in response to elevated copper, ATP7B moves from the Golgi to lysosomes and imports metal into their lumen. ATP7B enables lysosomes to undergo exocytosis through the interaction with p62 subunit of dynactin that allows lysosome translocation toward the canalicular pole of hepatocytes. Activation of lysosomal exocytosis stimulates copper clearance from the hepatocytes and rescues the most frequent Wilson-disease-causing ATP7B mutant to the appropriate functional site. Our findings indicate that lysosomes serve as an important intermediate in ATP7B trafficking, whereas lysosomal exocytosis operates as an integral process in copper excretion and hence can be targeted for therapeutic approaches to combat Wilson disease.

The cytosolic chaperone α-crystallin B rescues folding and compartmentalization of misfolded multispan transmembrane proteins

The α-crystallin B chain (CRYAB or HspB5) is a cytosolic chaperone belonging to the small heat shock protein family, which is known to help in the folding of cytosolic proteins. Here we show that CRYAB binds the mutant form of at least two multispan transmembrane proteins (TMPs), exerting an anti-aggregation activity. It rescues the folding of mutant Frizzled4, which is responsible for a rare autosomal dominant form of familial exudative vitreoretinopathy (Fz4-FEVR), and the mutant ATP7B Cu transporter (ATP7B-H1069Q) associated with a common form of Wilson's disease. In the case of Fz4-FEVR, CRYAB prevents the formation of inter-chain disulfide bridges between the lumenal ectodomains of the aggregated mutant chains, which enables correct folding and promotes appropriate compartmentalization on the plasma membrane. ATP7B-H1069Q, with help from CRYAB, folds into the proper conformation, moves to the Golgi complex, and responds to copper overload in the same manner as wild-type ATP7B. These findings strongly suggest that CRYAB plays a pivotal role, previously undetected, in the folding of multispan TMPs and, from the cytosol, is able to orchestrate folding events that take place in the lumen of the ER. Our results contribute to the explanation of the complex scenario behind multispan TMP folding; additionally, they serve to expose interesting avenues for novel therapeutic approaches.

When the position of a stent is incorrect

Gut perforation, secondary to the insertion of a biliary stent, is an uncommon but potentially life-threatening complication. The authors present the case of a patient with biliary stent dislocation and intestinal perforation. The diagnosis was suspected on the description on direct abdomen X-ray of a stent inserted in a right iliac artery.

Giant negative T-wave: always coronary artery disease?

CLINICAL CASE We describe a 82 years old patient with giant negative T waves in anterior and inferior leads at electrocardiogram (ECG) after pace-maker (PM) implantation because of total atrioventricular block, and we discuss about different cause of negative T waves at ECG. CONCLUSIONS Particularly, we remark that, after a long period of PM stimulation, a negative T waves at ECG without myocardial ischemia, defined as “electrical memory”, may appear if a spontaneous sinus rhythm occurs. The same phenomena is present in patients affected by intermittent left bundle-branch block.

The impairment of HCCS leads to MLS syndrome by activating a non-canonical cell death pathway in the brain and eyes

Mitochondrial-dependent (intrinsic) programmed cell death (PCD) is an essential homoeostatic mechanism that selects bioenergetically proficient cells suitable for tissue/organ development. However, the link between mitochondrial dysfunction, intrinsic apoptosis and developmental anomalies has not been demonstrated to date. Now we provide the evidence that non-canonical mitochondrial-dependent apoptosis explains the phenotype of microphthalmia with linear skin lesions (MLS), an X-linked developmental disorder caused by mutations in the holo-cytochrome c-type synthase (HCCS) gene. By taking advantage of a medaka model that recapitulates the MLS phenotype we demonstrate that downregulation of hccs, an essential player of the mitochondrial respiratory chain (MRC), causes increased cell death via an apoptosome-independent caspase-9 activation in brain and eyes. We also show that the unconventional activation of caspase-9 occurs in the mitochondria and is triggered by MRC impairment and overproduction of reactive oxygen species (ROS). We thus propose that HCCS plays a key role in central nervous system (CNS) development by modulating a novel non-canonical start-up of cell death and provide the first experimental evidence for a mechanistic link between mitochondrial dysfunction, intrinsic apoptosis and developmental disorders.

[Effectiveness of nasal positive pressure ventilation in the management of acute refractory left ventricular insufficiency]

BACKGROUND

Ehen refractory to optimal medical treatment cardiogenic pulmonary edema requires mechanical ventilation as a last therapeutic resource. In recent years an increasing number of authors reported their experience in the management of acute or subacute respiratory failure with non-invasive mechanical ventilation by nasal mask.

MATERIALS AND METHODS

Encouraged by the first promising results reported in literature we experimented this new therapeutic tool in a first group of seven elderly patients (mean age: 76.57--range: 65-89); they all had been admitted for severe cardiogenic pulmonary edema unresponsive to maximal doses of the conventional drugs available for treating acute decompensated heart failure. The enrolled patients were treated with intermittent ventilation administered by nasal mask at selected values of inspiratory positive airway pressure (IPAP) that were comprised between 10 and 20 cm H2O. At the same time an expiratory positive airway pressure (EPAP) at values comprised between 3 and 8 cm H2O was applied. Ventilation was continued for variable periods of 3-24 hours until acceptable values of PaO2 and PaCO2 were obtained. The ventilation modality was spontaneous, spontaneous-time or timed depending on the patients' level of consciousness at starting time.

RESULTS

A good short-term outcome was achieved in all the patients regardless of the ventilation modality applied. The main blood gas alteration was severe hypercapnia with acidosis in three patients, while the other four presented critical hypoxemia unresponsive to simple oxygen supply even if delivered by high-flow Venturi mask. Four of our seven patients were discharged from hospital in satisfactory haemodynamic conditions; the remaining three died during hospitalization from refractory heart failure.

CONCLUSIONS

In this our preliminary experience the therapeutic approach with nasal positive pressure ventilation (NPPV) and EPAP proved to be very effective to improve the signs and symptoms of acute refractory cardiogenic pulmonary edema as it avoided the need of invasive mechanical ventilation. It was well tolerated by all our patients; besides it was not difficult to use or time-consuming for physician and nurses. On the other hand it didn't modify our patients' medium or long-time prognosis which was strictly related to their preexisting left ventricular pump derangement.

[Recovery of pump function in ischemic hypokinetic cardiopathy subjects treated with weekly intermittent infusion of dobutamine. A clinical case]

The case is reported of a 69-year-old man with refractory heart failure due to ischemic cardiomyopathy. All other available treatments having failed and 250 mg doses of furosemide having been administered without success, dobutamine infusion was tried, at first with 72 hours of continuous infusion of 5 mcg/kg/min, followed by intermittent infusion at the same dosage, first with 12-h intervals, subsequently at the rate of 2-3 infusions weekly, and finally, after about 50 days, with a single weekly infusion. Clinical and hemodynamic results were brilliant with the patient passing from grade IV NYHA to grade II and from ejection fraction 21% (Teichholz M-mode measurement) to 55%, 14 months after the start of dobutamine treatment. Discussing the possible mechanisms of this favourable result, the authors stress the possible improvement of the contractility of the "stunned" or "hibernating" myocardial segments. On the basis of their experience and of data in the literature the authors underline the validity of a therapeutic protocol of intermittent dobutamine infusion for severe heart failure.

[Silent myocardial ischemia with raised ST tract in 2 octogenarian patients without ischemic cardiopathy]

The authors describe two recently observed cases of silent angina with ST segment elevation. The patients, both 80-years old, were submitted to 24-hour Holter examination to account for recurrent episodes of dizziness. The examination revealed silent angina with ST elevation concentrated mainly in the late evening and morning hours, accompanied by accelerated heart rate. Treatment with low diltiazem doses was completely successful.

[Chiari's network: persistence of the embryonic remnants of the valve of the sinus venosus in the right atrium. Echocardiographic and clinical analysis in a group of subjects]

As echocardiography is being used more often, its value and accuracy are becoming more fully appreciated, especially for identifying normal anatomic variants and their possible erroneous interpretation as pathologic states. We report the echocardiographic and clinical findings observed in sixteen subjects examined at our Cardiological Service in the period from January 1987 to April 1988. Mean age of these subjects is 40 +/- 27.04. Of these subjects, six are affected by other cardiac pathologies and ten are unaffected (Group A). First, we describe in all the patients M-mode and two dimensional patterns of persistence of the right venous sinus valve known as the Chiari network. This structure can present as a highly mobile, highly reflective echo target, which can be seen especially by means of the bi-dimensional technique. The Chiari network could be seen with all four standard approaches. The two most diagnostic views are, in our experience, the short axis parasternal view (62.5%), and the subcostal view (87.5%). In a great number of subjects (75%) the Chiari network could be seen in at least two approaches. Second, in Group A we make a clinical examination. Nine subjects in this group show the presence of a cardiac systolic murmur with vibratory characters from grade 1/6 to grade 3/6. 50% of the same patients presented supraventricular arrhythmias (particularly, two presented reciprocating paroxysmal supraventricular tachycardia and one paroxysmal atrial fibrillation). The significance of these findings is not clear yet. We, at least, emphasise that the Chiari network could be confused with other curvilinear highly mobile, echo targets such as right-heart vegetations, flail tricuspid leaflets, a small right-heart thrombus or even a pedunculated right heart tumor (especially right atrial myxoma). On the contrary, this structure might be considered a "normal anatomic variant".

[Dynamic left intraventricular obstruction in acute myocardial ischemia]

A case of a 60-year-old woman suffering from hypertension, who presented an episode of acute myocardial ischemia with an elevation of the ST segment in the anterior ECG lead, is reported. On examination, a transient loud systolic murmur was present; it completely disappeared soon after the cessation of acute myocardial ischemia. Doppler echocardiography was performed a few times, during and after the acute ischemia: it was able to show a sort of "hour-glass" deformation of the left ventricle due to the akinesia of the anterior and apical segments. This functional anatomic deformation hampers the outflow from the left ventricle thus creating a dynamic left intraventricular gradient, which is clearly shown by pulsed wave and continuous Doppler echocardiography.

[Partial rupture of biliary cyst of large dimensions. Clinical description and ultrasonic diagnosis]

The clinical case of an elderly patient hospitalised for acute abdomen type syndrome is reported. Investigation, particularly echography, pointed to a diagnosis of partially ruptured giant biliary cyst of the liver. The clinical pictures and the unusual features of this rare condition are discussed. Differential diagnosis with respect to echinococcosis and polycystic liver is examined.

[The hospitalized drug addict. Social assistance and therapeutic care]

Ninety drug addicts observed in 1973-83 were examined in a study of the main anamnestic and behavioural parameters, the reasons for hospitalisation, the presence of withdrawal symptoms during treatment and any prospects of long-term cure. In conclusion, it is emphasised that the low frequency of real withdrawal pathology often renders "scaled" treatment with methadone superfluous. Finally it is pointed out that in itself, the hospitalisation period can do almost nothing to break the addiction spiral unless it forms part of a wider prospect of global treatment.

[Physical health and drug dependence]

90 hospitalized drug addicts observed in 1979-83 were examined. The investigation of the main anamnestic, clinical and instrumental parameters made it possible to construct a profile of the main physical handicaps affecting drug addicts and the main pathologies they encounter. In conclusion it is emphasised that it is probably not the drug in itself but rather their unhealthy life style that is the primary cause of drug addicts' poor health.