Role of WD domain of ATG16L1 in maintaining autophagy and tissue homeostasis in mice

Macroautophagy or canonical autophagy, referred to as autophagy hereafter, delivers damaged proteins and organelles to lysosomes for degradation and plays important roles in maintaining tissue homeostasis by reducing tissue damage. During autophagy substrates are sequestered in doublemembraned autophagosomes within the cytoplasm which recruit LC3 to facilitate fusion with lysosomes. A related pathway, called non-canonical autophagy, conjugates LC3 to single-membraned endosomes, phagosomes or lysosomes during the entry of extracellular material. Examples include engulfment of neighbouring cells by entosis, uptake of apoptotic cells, and micropinocytosis. In phagocytic cells, such as macrophages and dendritic cells, recruitment of LC3 to phagosomes occurs during pathogen uptake and is called LC3-associated phagocytosis (LAP). The relative roles played by autophagy and non-canonical autophagy ‘in vivo’ are poorly understood. Studies on autophagy in mice have relied on inactivation of essential autophagy proteins, however these proteins are also required for non-canonical autophagy, and mouse models are defective in both pathways. The recruitment of LC3 to membranes during both, autophagy and non-canonical autophagy/ LAP, requires the E3 ligase-like activity of the ATG12–ATG5-ATG16L1 complex. The WD domain of ATG16L1 is required for non-canonical autophagy and LAP, but is not required for autophagy. This finding was employed to create mice defective in non-canonical autophagy and LAP by removing WD domain from the Atg16L1 gene. These mice (called E230) expressed the glutamate residues at 226 and 230 positions in the coiled-coil domain (CCD) of ATG16L1 protein required for binding with WIPI2, an interaction needed for autophagy. A second mouse model was generated that lacked the E230 residue required for autophagy and was called E226. MEFs from E226 mice were defective in both autophagy and non-canonical autophagy. E226 mice showed growth defects and analysis of liver, kidney, muscle and brain showed accumulation of autophagy substrates p62and LC3. MEFs from the E230 mice were defective in non-canonical autophagy but could activate autophagy. The E230 mice survived postnatal starvation and grew normally. Liver, kidney, brain and muscle of E230 mice maintained levels of autophagy substrates p62 and LC3 that were the same as littermate controls. Tissue damage associated with loss of autophagy such as presence of p62 inclusions and inflammation were observed in tissue of E226 mice but were absent from E230 mice. This comparative study suggests that autophagy maintains tissue homeostasis in mice independently of the WD domain of ATG16L1required for non-canonical autophagy/LAP. A comparison of ATG5-ATG12-ATG16L1 complexes formed in liver and brain suggested that autophagy in the brain may be less dependent on strong interactions between WIPI2 and ATG16L1 than in liver. It is possible that E226 mice, which lack E230 required for strong WIPI2 binding, maintain autophagy in the brain to survive neonatal starvation

The ATG5-binding and coiled coil domains of ATG16L1 maintain autophagy and tissue homeostasis in mice independently of the WD domain required for LC3 associated phagocytosis

Macroautophagy/autophagy delivers damaged proteins and organelles to lysosomes for degradation, and plays important roles in maintaining tissue homeostasis by reducing tissue damage. The translocation of LC3 to the limiting membrane of the phagophore, the precursor to the autophagosome, during autophagy provides a binding site for autophagy cargoes, and facilitates fusion with lysosomes. An autophagy-related pathway called LC3-associated phagocytosis (LAP) targets LC3 to phagosome and endosome membranes during uptake of bacterial and fungal pathogens, and targets LC3 to swollen endosomes containing particulate material or apoptotic cells. We have investigated the roles played by autophagy and LAP in vivo by exploiting the observation that the WD domain of ATG16L1 is required for LAP, but not autophagy. Mice lacking the linker and WD domains, activate autophagy, but are deficient in LAP. The LAP −/- mice survive postnatal starvation, grow at the same rate as littermate controls, and are fertile. The liver, kidney, brain and muscle of these mice maintain levels of autophagy cargoes such as LC3 and SQSTM1/p62 similar to littermate controls, and prevent accumulation of SQSTM1 inclusions and tissue damage associated with loss of autophagy. The results suggest that autophagy maintains tissue homeostasis in mice independently of LC3-associated phagocytosis. Further deletion of glutamate E230 in the coiled-coil domain required for WIPI2 binding produced mice with defective autophagy that survived neonatal starvation. Analysis of brain lysates suggested that interactions between WIPI2 and ATG16L1 were less critical for autophagy in the brain, which may allow a low level of autophagy to overcome neonatal lethality. Abbreviations: CCD: coiled-coil domain; CYBB/NOX2: cytochrome b-245: beta polypeptide; GPT/ALT: glutamic pyruvic transaminase: soluble; LAP: LC3-associated phagocytosis; LC3: microtubule-associated protein 1 light chain 3; MEF: mouse embryonic fibroblast; NOD: nucleotide-binding oligomerization domain; NADPH: nicotinamide adenine dinucleotide phosphate; RUBCN/Rubicon: RUN domain and cysteine-rich domain containing Beclin 1-interacting protein; SLE: systemic lupus erythematosus; SQSTM1/p62: sequestosome 1; TLR: toll-like receptor; TMEM: transmembrane protein; TRIM: tripartite motif-containing protein; UVRAG: UV radiation resistance associated gene; WD: tryptophan-aspartic acid; WIPI: WD 40 repeat domain: phosphoinositide interacting

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

Fluorescence microscopy: A tool to study autophagy

Autophagy is a cellular recycling process through which a cell degrades old and damaged cellular components such as organelles and proteins and the degradation products are reused to provide energy and building blocks. Dysfunctional autophagy is reported in several pathological situations. Hence, autophagy plays an important role in both cellular homeostasis and diseased conditions. Autophagy can be studied through various techniques including fluorescence based microscopy. With the advancements of newer technologies in fluorescence microscopy, several novel processes of autophagy have been discovered which makes it an essential tool for autophagy research. Moreover, ability to tag fluorescent proteins with sub cellular targets has enabled us to evaluate autophagy processes in real time under fluorescent microscope. In this article, we demonstrate different aspects of autophagy in two different model organisms i.e. yeast and mammalian cells, with the help of fluorescence microscopy

Interesting case of Mesenteric artery ischemia mimicking appendicitis: A case report

Acute mesenteric ischemia is sudden interruption of the blood supply to a segment of the small intestine. It may be non-occlusive (NOMI) or occlusive, with the primary etiology further defined as mesenteric arterial embolism, mesenteric arterial thrombosis, or mesenteric venous thrombosis. We reported a case of mesenteric artery ischemia mimicking appendicitis in 45 years old male patient

Additive Manufacturing Decision Support Systems : A Systematic Literature Review Discerning Current and Future Directions

Additive manufacturing (AM) was introduced the 1980's for rapid prototyping (RP) purposes but now AM provides complementary techniques to conventional manufacturing processes and offers advantages when components can be exacting, impossible, and too costly to be produced by conventional methods due to complex structures and geometric configurations, which require tailored designs. They are also often mass-customized components, with custom-made properties and low volume production requirements making AM the 'technology of choice' since its added-value aspects cannot be achieved by any other manufacturing technologies. These advancements in manufacturing, demand standardized fact-based decision support systems (DSSs), to support AM practitioners in their task selecting the most suitable techniques for given applications. Hence, this paper aims to increase the understanding of what - of how - DSSs are used in selecting and utilizing AM in various applications. This paper's core message, considering practical implications, is to guide and support AM researchers with an overview of the DSSs for AM landscape. This paper presents and compares different models and tools classified within four categories used as DSS for AM and identifies their advantages and disadvantages by conducting a 3-step systematic literature review (SLR). A total of 388 literatures were initially retrieved, and according to an inclusion criteria analysis, the literatures were evaluated. This is the first SLR emphasizing and synthesizing obtainable literatures on AM DSS. Until now, this topic has acquired narrow exploration; however, the authors believe it is of rapidly growing importance to both scientists and practitioners

An unusually large adenomatoid odontogenic tumor with involvement of the ethmoidal sinus: A rare case report

Adenomatoid odontogenic tumor (AOT) is an uncommon nonaggressive tumor of the odontogenic epithelium with duct-like structures and varying degrees of inductive changes in the stroma. It comprises only 0.1% of tumors of the jaw and 3% of all odontogenic tumors. The majority of the cases (88%) are diagnosed in the second and third decades of life. The incidence is higher in males than in females. The tumor has a predilection for the anterior maxilla, most commonly associated with maxillary canine; however, involvement of the maxillary antrum is extremely rare. We report an unusually large AOT of the maxilla along with the computed tomography images in a 17-year-old female patient encroaching the maxillary sinus, orbital floor, nasal septum, ethmoidal sinus on the right side. It was also associated with an impacted canine. The patient was subjected for complete enucleation along with the removal of the impacted tooth. To the best of our knowledge, it is the first time that such a large AOT with involvement of the ethmoidal sinus has been reported

Molecular dynamics simulation based study to analyse the properties of entrapped water between gold and graphene 2D interface

Heterostructures based on graphene and other 2D materials have received significant attention in recent years. However, it is challenging to fabricate them with an ultra-clean interface due to unwanted foreign molecules, which usually get introduced during their transfer to a desired substrate. Clean nanofabrication is critical for the utilization of these materials in 2D nanoelectronics devices and circuits, and therefore, it is important to understand the influence of the “non-ideal” interface. Inspired by the wet-transfer process of the CVD-grown graphene, herein, we present an atomistic simulation of the graphene–Au interface, where water molecules often get trapped during the transfer process. By using molecular dynamics (MD) simulations, we investigated the structural variations of the trapped water and the traction–separation curve derived from the graphene–Au interface at 300 K. We observed the formation of an ice-like structure with square-ice patterns when the thickness of the water film was &lt;5 Å. This could cause undesirable strain in the graphene layer and hence affect the performance of devices developed from it. We also observed that at higher thicknesses the water film is predominantly present in the liquid state. The traction separation curve showed that the adhesion of graphene is better in the presence of an ice-like structure. This study explains the behaviour of water confined at the nanoscale region and advances our understanding of the graphene–Au interface in 2D nanoelectronics devices and circuits

Sensitivity Analysis of ZnO NWs Based Soft Capacitive Pressure Sensors Using Finite Element Modeling

Pressure sensors make an important component of electronic skin and its application in robotics, human-machine interfaces, and health monitoring. In this regard, soft capacitive sensors based on elastomeric dielectric materials and piezoelectric nanowires (NWs) have been shown to have good sensitivity, particularly in the low-pressure range of 0-10 kPa. In this work, we have simulated the capacitive sensors using finite element methods (FEM) to investigate the effect of piezoelectric properties of ZnO NWs incorporated into a polydimethylsiloxane (PDMS) dielectric material. Effect of NWs orientation and their dimensions on the sensitivity of the sensor have been studied. Simulations shows that with ZnO NWs in the PDMS matrix the sensors show higher sensitivity in low pressure range (0-10 kPa) than the bare PDMS based sensors. The estimated values and trends observed in this study were found to have good match with experimental results. Further, the simulation results show that the NWs aspect ratio could also influence the sensitivity of capacitive pressure sensors. The presented study shows the potential for using FEM for optimization of sensor design