ABSTRACT
Polymers are endocytosed and hydrolysed by lysosomal enzymes to generate transportable solutes. While the transport of diverse organic solutes across the plasma membrane is well studied, their necessary ongoing efflux from the endocytic fluid into the cytosol is poorly appreciated by comparison. Myeloid cells that employ specialized types of endocytosis, that is, phagocytosis and macropinocytosis, are highly dependent on such transport pathways to prevent the build-up of hydrostatic pressure that otherwise offsets lysosomal dynamics including vesiculation, tubulation and fission. Without undergoing rupture, we found that lysosomes incurring this pressure owing to defects in solute efflux, are unable to retain luminal Na+, which collapses its gradient with the cytosol. This cation 'leak' is mediated by pressure-sensitive channels resident to lysosomes and leads to the inhibition of mTORC1, which is normally activated by Na+-coupled amino acid transporters driven by the Na+ gradient. As a consequence, the transcription factors TFEB/TFE3 are made active in macrophages with distended lysosomes. In addition to their role in lysosomal biogenesis, TFEB/TFE3 activation causes the release of MCP-1/CCL2. In catabolically stressed tissues, defects in efflux of solutes from the endocytic pathway leads to increased monocyte recruitment. Here we propose that macrophages respond to a pressure-sensing pathway on lysosomes to orchestrate lysosomal biogenesis as well as myeloid cell recruitment.
Subject(s)
Basic Helix-Loop-Helix Leucine Zipper Transcription Factors , Lysosomes , Macrophages , Mechanistic Target of Rapamycin Complex 1 , Basic Helix-Loop-Helix Leucine Zipper Transcription Factors/metabolism , Basic Helix-Loop-Helix Leucine Zipper Transcription Factors/genetics , Lysosomes/metabolism , Animals , Macrophages/metabolism , Mice , Mechanistic Target of Rapamycin Complex 1/metabolism , Sodium/metabolism , Chemokine CCL2/metabolism , Chemokine CCL2/genetics , Mice, Inbred C57BL , Hydrostatic Pressure , Humans , Mice, KnockoutABSTRACT
Dynein cytoplasmic 1 light intermediate chain 1 (LIC1, DYNC1LI1) is a core subunit of the dynein motor complex. The LIC1 subunit also interacts with various cargo adaptors to regulate Rab-mediated endosomal recycling and lysosomal degradation. Defects in this gene are predicted to alter dynein motor function, Rab binding capabilities, and cytoplasmic cargo trafficking. Here, we have identified a dync1li1 zebrafish mutant, harboring a premature stop codon at the exon 12/13 splice acceptor site, that displays increased angiogenesis. In vitro, LIC1-deficient human endothelial cells display increases in cell surface levels of the pro-angiogenic receptor VEGFR2, SRC phosphorylation, and Rab11-mediated endosomal recycling. In vivo, endothelial-specific expression of constitutively active Rab11a leads to excessive angiogenesis, similar to the dync1li1 mutants. Increased angiogenesis is also evident in zebrafish harboring mutations in rilpl1/2, the adaptor proteins that promote Rab docking to Lic1 to mediate lysosomal targeting. These findings suggest that LIC1 and the Rab-adaptor proteins RILPL1 and 2 restrict angiogenesis by promoting degradation of VEGFR2-containing recycling endosomes. Disruption of LIC1- and RILPL1/2-mediated lysosomal targeting increases Rab11-mediated recycling endosome activity, promoting excessive SRC signaling and angiogenesis.
ABSTRACT
Lysosomes are membrane-bound organelles that degrade diverse biomolecules and regulate a multitude of other essential processes including cell growth and metabolism, signaling, plasma membrane repair and infection. Such diverse functions of lysosomes are highly coordinated in space and time and are therefore tightly coupled to the directional transport of the organelles within the cytoplasm. Thus, robust quantitative assessments of lysosome positioning within the cell provide a valuable tool for researchers interested in understanding these multifunctional organelles. Here, we present point-by-point methodology to measure lysosome positioning by two straight forward and widely used techniques: shell analysis and line scan.
Subject(s)
Lysosomes , Signal Transduction , Lysosomes/metabolismABSTRACT
The small GTPase ARL8 associates with endolysosomes, leading to the recruitment of several effectors that couple endolysosomes to kinesins for anterograde transport along microtubules, and to tethering factors for eventual fusion with other organelles. Herein we report the identification of the RUN- and FYVE-domain-containing proteins RUFY3 and RUFY4 as ARL8 effectors that promote coupling of endolysosomes to dynein-dynactin for retrograde transport along microtubules. Using various methodologies, we find that RUFY3 and RUFY4 interact with both GTP-bound ARL8 and dynein-dynactin. In addition, we show that RUFY3 and RUFY4 promote concentration of endolysosomes in the juxtanuclear area of non-neuronal cells, and drive redistribution of endolysosomes from the axon to the soma in hippocampal neurons. The function of RUFY3 in retrograde transport contributes to the juxtanuclear redistribution of endolysosomes upon cytosol alkalinization. These studies thus identify RUFY3 and RUFY4 as ARL8-dependent, dynein-dynactin adaptors or regulators, and highlight the role of ARL8 in the control of both anterograde and retrograde endolysosome transport.
Subject(s)
Dyneins , Microtubules , Dynactin Complex , Dyneins/metabolism , Endosomes/metabolism , Kinesins , Microtubule-Associated Proteins/metabolism , Microtubules/metabolismABSTRACT
The ability of endolysosomal organelles to move within the cytoplasm is essential for the performance of their functions. Long-range movement involves coupling of the endolysosomes to motor proteins that carry them along microtubule tracks. This movement is influenced by interactions with other organelles, but the mechanisms involved are incompletely understood. Herein we show that the sorting nexin SNX19 tethers endolysosomes to the endoplasmic reticulum (ER), decreasing their motility and contributing to their concentration in the perinuclear area of the cell. Tethering depends on two N-terminal transmembrane domains that anchor SNX19 to the ER, and a PX domain that binds to phosphatidylinositol 3-phosphate on the endolysosomal membrane. Two other domains named PXA and PXC negatively regulate the interaction of SNX19 with endolysosomes. These studies thus identify a mechanism for controlling the motility and positioning of endolysosomes that involves tethering to the ER by a sorting nexin.
Subject(s)
Endoplasmic Reticulum/metabolism , Endosomes/metabolism , Lysosomes/metabolism , Sorting Nexins/metabolism , Cell Line, Tumor , Endoplasmic Reticulum/ultrastructure , Endosomes/ultrastructure , Humans , Lysosomes/ultrastructure , Phosphatidylinositol Phosphates/metabolism , Protein Binding , Protein Domains , Protein Transport , Sorting Nexins/chemistrySubject(s)
Membranes/physiology , Animals , Biological Transport/physiology , Humans , Lysosomes/physiology , Mammals/physiologyABSTRACT
Macrophages continuously survey their environment in search of pathogens or apoptotic corpses or debris. Targets intended for clearance expose ligands that initiate their phagocytosis ("eat me" signals), while others avoid phagocytosis by displaying inhibitory ligands ("don't eat me" signals). We report that such ligands can be obscured by the glycosaminoglycans and glycoproteins that coat pathogenic as well as malignant phagocytic targets. In addition, a reciprocal barrier of self-synthesized or acquired glycocalyx components on the macrophage surface shrouds phagocytic receptors, curtailing their ability to engage particles. The coating layers of macrophages and their targets hinder phagocytosis by both steric and electrostatic means. Their removal by enzymatic means is shown to markedly enhance phagocytic efficiency. In particular, we show that the removal of mucins, which are overexpressed in cancer cells, facilitates their clearance. These results shed light on the physical barriers that modulate phagocytosis, which have been heretofore underappreciated. VIDEO ABSTRACT.
Subject(s)
Candidiasis, Invasive/immunology , Glycocalyx/immunology , Neoplasms/immunology , Phagocytosis/immunology , Adult , Animals , Biological Products/pharmacology , Biological Products/therapeutic use , CD47 Antigen/antagonists & inhibitors , CD47 Antigen/immunology , CD47 Antigen/metabolism , Candida albicans/immunology , Candida albicans/metabolism , Candidiasis, Invasive/microbiology , Disease Models, Animal , Female , Glycocalyx/metabolism , Glycosaminoglycans/metabolism , Healthy Volunteers , Humans , Hyaluronic Acid/metabolism , Immunoglobulin G/pharmacology , Immunoglobulin G/therapeutic use , MCF-7 Cells , Macrophages/drug effects , Macrophages/immunology , Macrophages/metabolism , Male , Mice , Mucins/metabolism , Neoplasms/drug therapy , Neoplasms/pathology , Peritoneum/immunology , Peritoneum/microbiology , Phagocytes/drug effects , Phagocytes/immunology , Phagocytes/metabolism , Phagocytosis/drug effects , Primary Cell Culture , RAW 264.7 Cells , Synovial Fluid/cytology , Synovial Fluid/immunology , Synovial Fluid/metabolism , Young AdultABSTRACT
Eukaryotic cells employ diverse uptake mechanisms depending on their specialized functions. While such mechanisms vary widely in their defining criteria: scale, molecular machinery utilized, cargo selection, and cargo destination, to name a few, they all result in the internalization of extracellular solutes and fluid into membrane-bound endosomes. Upon scission from the plasma membrane, this compartment is immediately subjected to extensive remodeling which involves tubulation and vesiculation/budding of the limiting endomembrane. This is followed by a maturation process involving concomitant retrograde transport by microtubule-based motors and graded fusion with late endosomes and lysosomes, organelles that support the degradation of the internalized content. Here we review an important determinant for sorting and trafficking in early endosomes and in lysosomes; the control of tension on the endomembrane. Remodeling of endomembranes is opposed by high tension (caused by high hydrostatic pressure) and supported by the relief of tension. We describe how the timely and coordinated efflux of major solutes along the endocytic pathway affords the cell control over such tension. The channels and transporters that expel the smallest components of the ingested medium from the early endocytic fluid are described in detail as these systems are thought to enable endomembrane deformation by curvature-sensing/generating coat proteins. We also review similar considerations for the lysosome where resident hydrolases liberate building blocks from luminal macromolecules and transporters flux these organic solutes to orchestrate trafficking events. How the cell directs organellar trafficking based on the luminal contents of organelles of the endocytic pathway is not well-understood, however, we propose that the control over membrane tension by solute transport constitutes one means for this to ensue.
ABSTRACT
Despite ongoing (macro)pinocytosis of extracellular fluid, the volume of the endocytic pathway remains unchanged. To investigate the underlying mechanism, we used high-resolution video imaging to analyze the fate of macropinosomes formed by macrophages in vitro and in situ. Na+, the primary cationic osmolyte internalized, exited endocytic vacuoles via two-pore channels, accompanied by parallel efflux of Cl- and osmotically coupled water. The resulting shrinkage caused crenation of the membrane, which fostered recruitment of curvature-sensing proteins. These proteins stabilized tubules and promoted their elongation, driving vacuolar remodeling, receptor recycling, and resolution of the organelles. Failure to resolve internalized fluid impairs the tissue surveillance activity of resident macrophages. Thus, osmotically driven increases in the surface-to-volume ratio of endomembranes promote traffic between compartments and help to ensure tissue homeostasis.
Subject(s)
Immunologic Surveillance , Macrophages/immunology , Pinocytosis/immunology , Animals , Calcium Channels/genetics , Calcium Channels/physiology , Endosomes/immunology , Ion Transport , Lipids/immunology , Mice , Mice, Knockout , Organelles/immunology , Osmosis , Sodium/metabolism , Transient Receptor Potential Channels/genetics , Vacuoles/immunologyABSTRACT
The mechanisms that govern organelle adaptation and remodelling remain poorly defined. The endo-lysosomal system degrades cargo from various routes, including endocytosis, phagocytosis, and autophagy. For phagocytes, endosomes and lysosomes (endo-lysosomes) are kingpin organelles because they are essential to kill pathogens and process and present antigens. During phagocyte activation, endo-lysosomes undergo a morphological transformation, going from a collection of dozens of globular structures to a tubular network in a process that requires the phosphatidylinositol-3-kinase-AKT-mechanistic target of rapamycin (mTOR) signalling pathway. Here, we show that the endo-lysosomal system undergoes an expansion in volume and holding capacity during phagocyte activation within 2 h of lipopolysaccharides (LPS) stimulation. Endo-lysosomal expansion was paralleled by an increase in lysosomal protein levels, but this was unexpectedly largely independent of the transcription factor EB (TFEB) and transcription factor E3 (TFE3), which are known to scale up lysosome biogenesis. Instead, we demonstrate a hitherto unappreciated mechanism of acute organelle expansion via mTOR Complex 1 (mTORC1)-dependent increase in translation, which appears to be mediated by both S6Ks and 4E-BPs. Moreover, we show that stimulation of RAW 264.7 macrophage cell line with LPS alters translation of a subset but not all of mRNAs encoding endo-lysosomal proteins, thereby suggesting that endo-lysosome expansion is accompanied by functional remodelling. Importantly, mTORC1-dependent increase in translation activity was necessary for efficient and rapid antigen presentation by dendritic cells. Collectively, we identified a previously unknown and functionally relevant mechanism for endo-lysosome expansion that relies on mTORC1-dependent translation to stimulate endo-lysosome biogenesis in response to an infection signal.
Subject(s)
Antigen Presentation/physiology , Basic Helix-Loop-Helix Leucine Zipper Transcription Factors/metabolism , Lysosomes/metabolism , Phagocytes/metabolism , Animals , Autophagy , Endosomes/drug effects , Endosomes/metabolism , Female , Lipopolysaccharides/pharmacology , Lysosomes/drug effects , Macrophage Activation , Macrophages/metabolism , Mechanistic Target of Rapamycin Complex 1/metabolism , Mice , Mice, Inbred C3H , Mice, Inbred C57BL , Phagocytes/drug effects , Phagocytosis , Phosphatidylinositol 3-Kinases/metabolism , Proteins/metabolism , Proto-Oncogene Proteins c-akt/metabolism , RAW 264.7 Cells , Signal Transduction , TOR Serine-Threonine Kinases/metabolismABSTRACT
We report the development and characterization of a method, named reversible association with motor proteins (RAMP), for manipulation of organelle positioning within the cytoplasm. RAMP consists of coexpressing in cultured cells (i) an organellar protein fused to the streptavidin-binding peptide (SBP) and (ii) motor, neck, and coiled-coil domains from a plus-end-directed or minus-end-directed kinesin fused to streptavidin. The SBP-streptavidin interaction drives accumulation of organelles at the plus or minus end of microtubules, respectively. Importantly, competition of the streptavidin-SBP interaction by the addition of biotin to the culture medium rapidly dissociates the motor construct from the organelle, allowing restoration of normal patterns of organelle transport and distribution. A distinctive feature of this method is that organelles initially accumulate at either end of the microtubule network in the initial state and are subsequently released from this accumulation, allowing analyses of the movement of a synchronized population of organelles by endogenous motors.
Subject(s)
Cytological Techniques/methods , Molecular Motor Proteins/metabolism , Organelles/metabolism , Streptavidin/metabolism , Axons/metabolism , Axons/ultrastructure , Biological Transport , Biotin/metabolism , Dendrites/metabolism , Dendrites/ultrastructure , HeLa Cells , Humans , Organelles/ultrastructure , Reproducibility of ResultsABSTRACT
High-throughput screening identified 5 chemical analogs (termed the WX8-family) that disrupted 3 events in lysosome homeostasis: (1) lysosome fission via tubulation without preventing homotypic lysosome fusion; (2) trafficking of molecules into lysosomes without altering lysosomal acidity, and (3) heterotypic fusion between lysosomes and autophagosomes. Remarkably, these compounds did not prevent homotypic fusion between lysosomes, despite the fact that homotypic fusion required some of the same machinery essential for heterotypic fusion. These effects varied 400-fold among WX8-family members, were time and concentration dependent, reversible, and resulted primarily from their ability to bind specifically to the PIKFYVE phosphoinositide kinase. The ability of the WX8-family to prevent lysosomes from participating in macroautophagy/autophagy suggested they have therapeutic potential in treating autophagy-dependent diseases. In fact, the most potent family member (WX8) was 100-times more lethal to 'autophagy-addicted' melanoma A375 cells than the lysosomal inhibitors hydroxychloroquine and chloroquine. In contrast, cells that were insensitive to hydroxychloroquine and chloroquine were also insensitive to WX8. Therefore, the WX8-family of PIKFYVE inhibitors provides a basis for developing drugs that could selectively kill autophagy-dependent cancer cells, as well as increasing the effectiveness of established anti-cancer therapies through combinatorial treatments. Abbreviations: ACTB: actin beta; Baf: bafilomycin A1; BECN1: beclin 1; BODIPY: boron-dipyrromethene; BORC: BLOC-1 related complex; BRAF: B-Raf proto-oncogene, serine/threonine kinase; BSA: bovine serum albumin; CTSD: cathepsin D; CQ: chloroquine; DNA: deoxyribonucleic acid; EC50: half maximal effective concentration; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GFP: green fluorescent protein; HCQ: hydroxychloroquine; HOPS complex: homotypic fusion and protein sorting complex; Kd: equilibrium binding constant; IC50: half maximal inhibitory concentration; KO: knockout; LAMP1: lysosomal associated membrane protein 1; MAP1LC3A: microtubule associated protein 1 light chain 3 alpha; MES: 2-(N-morpholino)ethanesulphonic acid; MTOR: mechanistic target of rapamycin kinase; µM: micromolar; NDF: 3-methylbenzaldehyde (2,6-dimorpholin-4-ylpyrimidin-4-yl)hydrazine;NEM: N-ethylmaleimide; NSF: N-ethylmaleimide sensitive factor; PBS: phosphate-buffered saline; PIKFYVE: phosphoinositide kinase, FYVE-type zinc finger containing; PIP4K2C: phosphatidylinositol-5-phosphate 4-kinase type 2 gamma; PtdIns3P: phosphatidylinositol 3-phosphate; PtdIns(3,5)P2: phosphatidylinositol 3,5-biphosphate; RFP: red fluorescent protein; RPS6: ribosomal protein S6; RPS6KB1: ribosomal protein S6 kinase B1; SQSTM1: sequestosome 1; TWEEN 20: polysorbate 20; V-ATPase: vacuolar-type H+-translocating ATPase; VPS39: VPS39 subunit of HOPS complex; VPS41: VPS41 subunit of HOPS complex; WWL: benzaldehyde [2,6-di(4-morpholinyl)-4-pyrimidinyl]hydrazone; WX8: 1H-indole-3-carbaldehyde [4-anilino-6-(4-morpholinyl)-1,3,5-triazin-2-yl]hydrazine; XBA: N-(3-chloro-4-fluorophenyl)-4,6-dimorpholino-1,3,5-triazin-2-amine hydrochloride; XB6: N-(4-ethylphenyl)-4,6-dimorpholino-1,3,5-triazin-2-amine hydrochloride.
Subject(s)
Autophagy/drug effects , Homeostasis/drug effects , Lysosomes/drug effects , Neoplasms/pathology , Phosphoinositide-3 Kinase Inhibitors/pharmacology , Animals , Autophagosomes/drug effects , Autophagosomes/metabolism , Autophagy/physiology , Cells, Cultured , HEK293 Cells , HeLa Cells , Humans , Lysosomes/metabolism , Male , Mice , Neoplasms/drug therapy , Neoplasms/metabolism , Phosphatidylinositol 3-Kinases/metabolism , Phosphoinositide-3 Kinase Inhibitors/therapeutic use , Proto-Oncogene Mas , RAW 264.7 CellsABSTRACT
Excessive uptake of oxidized low-density lipoproteins (oxLDL) by macrophages is a fundamental characteristic of atherosclerosis. However, signals regulating the engagement of these ligands remain elusive. Using single-molecule imaging, we discovered a mechanism whereby chemokine signaling enhanced binding of oxLDL to the scavenger receptor, CD36. By activating the Rap1-GTPase, chemokines promoted integrin-mediated adhesion of macrophages to the substratum. As a result, cells exhibited pronounced remodeling of the cortical actin cytoskeleton that increased CD36 clustering. Remarkably, CD36 clusters formed predominantly within actin-poor regions of the cortex, and these regions were primed to engage oxLDL. In accordance with enhanced ligand engagement, prolonged exposure of macrophages to chemokines amplified the accumulation of esterified cholesterol, thereby accentuating the foam cell phenotype. These findings imply that the activation of integrins by chemokine signaling exerts feedforward control over receptor clustering and effectively alters the threshold for cells to engage ligands.
Subject(s)
CD36 Antigens/metabolism , Chemokines/metabolism , Lipoproteins, LDL/toxicity , Signal Transduction/drug effects , Actin Cytoskeleton/drug effects , Animals , CD36 Antigens/deficiency , CD36 Antigens/genetics , Chemokine CCL2/metabolism , Chemokine CX3CL1/metabolism , Chemokine CXCL12/metabolism , Foam Cells/cytology , Foam Cells/metabolism , HeLa Cells , Humans , Macrophages/cytology , Macrophages/drug effects , Macrophages/metabolism , Mice , Mice, Knockout , Microscopy, Confocal , Protein Binding , RAW 264.7 Cells , TransfectionABSTRACT
Macrophages and dendritic cells exposed to lipopolysaccharide (LPS) convert their lysosomes from small, punctate organelles into a network of tubules. Tubular lysosomes have been implicated in phagosome maturation, retention of fluid phase, and antigen presentation. There is a growing appreciation that lysosomes act as sensors of stress and the metabolic state of the cell through the kinase mTOR. Here we show that LPS stimulates mTOR and that mTOR is required for LPS-induced lysosome tubulation and secretion of major histocompatibility complex II in macrophages and dendritic cells. Specifically, we show that the canonical phosphatidylinositol 3-kinase-Akt-mTOR signaling pathway regulates LPS-induced lysosome tubulation independently of IRAK1/4 and TBK. Of note, we find that LPS treatment augmented the levels of membrane-associated Arl8b, a lysosomal GTPase required for tubulation that promotes kinesin-dependent lysosome movement to the cell periphery, in an mTOR-dependent manner. This suggests that mTOR may interface with the Arl8b-kinesin machinery. To further support this notion, we show that mTOR antagonists can block outward movement of lysosomes in cells treated with acetate but have no effect in retrograde movement upon acetate removal. Overall our work provides tantalizing evidence that mTOR plays a role in controlling lysosome morphology and trafficking by modulating microtubule-based motor activity in leukocytes.
Subject(s)
Dendritic Cells/metabolism , Macrophages/metabolism , TOR Serine-Threonine Kinases/metabolism , ADP-Ribosylation Factors/metabolism , Animals , Antigen Presentation/immunology , Dendritic Cells/immunology , Endosomes/metabolism , Female , Lysosomes/immunology , Lysosomes/metabolism , Macrophages/immunology , Mice , Mice, Inbred C57BL , Oncogene Protein v-akt/metabolism , Phosphatidylinositol 3-Kinases/metabolism , Protein Transport , RAW 264.7 Cells , Signal Transduction , TOR Serine-Threonine Kinases/immunology , Toll-Like Receptor 4/metabolismABSTRACT
Macrophages internalize and sequester pathogens into a phagosome. Phagosomes then sequentially fuse with endosomes and lysosomes, converting into degradative phagolysosomes. Phagosome maturation is a complex process that requires regulators of the endosomal pathway including the phosphoinositide lipids. Phosphatidylinositol-3-phosphate and phosphatidylinositol-3,5-bisphosphate (PtdIns(3,5)P2 ), which respectively control early endosomes and late endolysosomes, are both required for phagosome maturation. Inhibition of PIKfyve, which synthesizes PtdIns(3,5)P2 , blocked phagosome-lysosome fusion and abated the degradative capacity of phagosomes. However, it is not known how PIKfyve and PtdIns(3,5)P2 participate in phagosome maturation. TRPML1 is a PtdIns(3,5)P2 -gated lysosomal Ca(2+) channel. Because Ca(2+) triggers membrane fusion, we postulated that TRPML1 helps mediate phagosome-lysosome fusion. Using Fcγ receptor-mediated phagocytosis as a model, we describe our research showing that silencing of TRPML1 hindered phagosome acquisition of lysosomal markers and reduced the bactericidal properties of phagosomes. Specifically, phagosomes isolated from TRPML1-silenced cells were decorated with lysosomes that docked but did not fuse. We could rescue phagosome maturation in TRPML1-silenced and PIKfyve-inhibited cells by forcible Ca(2+) release with ionomycin. We also provide evidence that cytosolic Ca(2+) concentration increases upon phagocytosis in a manner dependent on TRPML1 and PIKfyve. Overall, we propose a model where PIKfyve and PtdIns(3,5)P2 activate TRPML1 to induce phagosome-lysosome fusion.
Subject(s)
Phagosomes/metabolism , Transient Receptor Potential Channels/metabolism , Animals , Calcium/metabolism , Cell Line , Lysosomes/metabolism , Macrophages/metabolism , Mice , Phagocytosis , Phosphatidylinositol 3-Kinases/metabolism , Phosphatidylinositols/metabolism , Transient Receptor Potential Channels/geneticsABSTRACT
In General Hospital setting, where varieties of patients are included in neurorehabilitation process, set of multidisciplinary functional tests were established, as a routine in daily work. Tests were done by physiotherapists and occupational therapists who were members of rehabilitation team. Our aim was to select the tests which can be used as a routine and are applicable for different neurological impairments in daily work. Tests were applied to inpatients admitted to the Medical, Trauma, Neurology and Neurosurgery wards in the Rashid Hospital, DOHMS, Dubai. Fifty inpatients with different neurological impairments admitted to totally 8 wards, were tested in the beginning of rehabilitation process and on discharge from the hospital. Nine tests were used as standardized tests for measuring motor, cognitive, focal impairment, ADL activities and disability: Motricity Index, Trunk Control Test, Standing Balance score, Functional Ambulation Categories test, Mini Mental State Examination, Canadian Neurological Scale, Action Research Arm test, Bartel Index and Functional Independent Measurements. FIM, Motricity Index and Trunk Control Test were applicable for all tested patients, with required adaptation for different neurological conditions within the same score. Other tests were not applicable for all patients as routine, but there were very useful for certain number of patients as a measurement of functional improvement. It is very important to have proper setup of tests, which are simple, reliable and valid for measuring impairment, disability and handicap and which can be used as standardized part of assessment protocol. Also, they must be applicable for different neurological impairments to monitor treatment progress. Combination of tests performed by different professionals and comprehensive approach of all team members is very important for measuring outcomes in rehabilitation and evaluating patient's impairment and disability. Proper hospital setup, optimal number of staff, good communication and team work are leading to better outcome in neurorehabilitation process.