Endocytosis, phagocytosis, and macropinocytosis are fundamental processes that enable cells to sample their environment, eliminate pathogens and apoptotic bodies, and regulate the expression of surface components. While a great deal of effort has been devoted over many years to understanding the proteins involved in these processes, the important contribution of phospholipids has only recently been appreciated. This review is an attempt to collate and analyze the rapidly emerging evidence documenting the role of phospholipids in clathrin-mediated endocytosis, phagocytosis, and macropinocytosis. A primer on phospholipid biosynthesis, catabolism, subcellular distribution, and transport is presented initially, for reference, together with general considerations of the effects of phospholipids on membrane curvature and charge. This is followed by a detailed analysis of the critical functions of phospholipids in the internalization processes and in the maturation of the resulting vesicles and vacuoles as they progress along the endo-lysosomal pathway.
Two inositol 5-phosphatases, OCRL and Inpp5B, become associated with nascent phagosomes. Both phosphatases associate with the adaptor APPL1, which is recruited to phagosomes by active Rab5. The phosphatases complete the elimination of PI(4,5)P2 and PI(3,4,5)P3, facilitating phagosome closure and termination of Akt activation.
Although intracranial pressure (ICP) is essential to guide management of patients suffering from acute brain diseases, this signal is often neglected outside the neurocritical care environment. This is mainly attributed to the intrinsic risks of the available invasive techniques, which have prevented ICP monitoring in many conditions affecting the intracranial homeostasis, from mild traumatic brain injury to liver encephalopathy. In such scenario, methods for non-invasive monitoring of ICP (nICP) could improve clinical management of these conditions. A review of the literature was performed on PUBMED using the search keywords ‘Transcranial Doppler non-invasive intracranial pressure.’ Transcranial Doppler (TCD) is a technique primarily aimed at assessing the cerebrovascular dynamics through the cerebral blood flow velocity (FV). Its applicability for nICP assessment emerged from observation that some TCD-derived parameters change during increase of ICP, such as the shape of FV pulse waveform or pulsatility index. Methods were grouped as: based on TCD pulsatility index; aimed at non-invasive estimation of cerebral perfusion pressure and model-based methods. Published studies present with different accuracies, with prediction abilities (AUCs) for detection of ICP ≥20 mmHg ranging from 0.62 to 0.92. This discrepancy could result from inconsistent assessment measures and application in different conditions, from traumatic brain injury to hydrocephalus and stroke. Most of the reports stress a potential advantage of TCD as it provides the possibility to monitor changes of ICP in time. Overall accuracy for TCD-based methods ranges around ±12 mmHg, with a great potential of tracing dynamical changes of ICP in time, particularly those of vasogenic nature.
Phagocytes spontaneously ruffle as they probe their environment and take up antigens. These cells are uniquely enriched in phosphatidic acid, which is necessary for ruffling and macropinocytosis.
Phagosomes formed by engagement of complement receptors (CR3) are moved within macrophages by PI3K-driven formation of actin “comet tails” on the phagosomal membrane.
IMPORTANCE Most clinical trials assessing systemic immunomodulatory treatments for patients with atopic dermatitis are placebo-controlled. OBJECTIVE To compare the effectiveness and safety of systemic immunomodulatory treatments for patients with atopic dermatitis in a systematic review and network meta-analysis. DATA SOURCES The Cochrane Central Register of Controlled Trials, MEDLINE, Embase, Latin American and Caribbean Health Science Information database, Global Resource of Eczema Trials database, and clinical trial registries were searched from inception to October 28, 2019. STUDY SELECTION English-language randomized clinical trials of 8 weeks or more of treatment with systemic immunomodulatory medications for moderate to severe atopic dermatitis were included. Titles, abstracts, and articles were screened in duplicate. Of 10 324 citations, 39 trials were included. DATA EXTRACTION AND SYNTHESIS Data were extracted in duplicate, and the review adhered to Preferred Reporting Items for Systematic Reviews and Meta-analyses for Network Meta-Analyses guidelines. Random-effects bayesian network meta-analyses were performed and certainty of evidence was assessed using Grading of Recommendations Assessment, Development and Evaluation criteria. MAIN OUTCOMES AND MEASURES Prespecified outcomes were change in signs of disease, symptoms, quality of life, itch, withdrawals, and serious adverse events. RESULTS A total of 39 trials with 6360 patients examining 20 medications and placebo were included. Most trials were conducted for adults receiving up to 16 weeks of therapy. Dupilumab, 300 mg every 2 weeks, was associated with improvement in the Eczema Area and Severity Index score vs placebo (mean difference, 11.3-point reduction; 95% credible interval [CrI], 9.7-13.1 [high certainty]). Cyclosporine (standardized mean difference, −1.1; 95% CrI, −1.7 to −0.5 [low certainty]) and dupilumab (standardized mean difference, −0.9; 95% CrI, −1.0 to −0.8 [high certainty]) were similarly effective vs placebo in clearing clinical signs of atopic dermatitis and may be superior to methotrexate (standardized mean difference, −0.6; 95% CrI, −1.1 to 0.0 [low certainty]) and azathioprine (standardized mean difference, −0.4; 95% CrI, −0.8 to −0.1 [low certainty]). Several investigational medications for atopic dermatitis are promising, but data to date are limited to small early-phase trials. Safety analyses were limited by low event rates. CONCLUSIONS AND RELEVANCE Dupilumab and cyclosporine may be more effective for up to 16 weeks of treatment than methotrexate and azathioprine for treating adult patients with atopic dermatitis. More studies directly comparing established and novel treatments beyond 16 weeks are needed and will be incorporated into future updates of this review.
Elevation of intracranial pressure (ICP) may occur in many diseases, and therefore the ability to measure it noninvasively would be useful. Flow velocity signals from transcranial Doppler (TCD) have been used to estimate ICP; however, the relative accuracy of these methods is unclear. This study aimed to compare four previously described TCD-based methods with directly measured ICP in a prospective cohort of traumatic brain-injured patients. Noninvasive ICP (nICP) was obtained using the following methods: 1) a mathematical ''black-box'' model based on interaction between TCD and arterial blood pressure (nICP_BB); 2) based on diastolic flow velocity (nICP_FVd); 3) based on critical closing pressure (nICP_CrCP); and 4) based on TCD-derived pulsatility index (nICP_PI). In time domain, for recordings including spontaneous changes in ICP greater than 7 mm Hg, nICP_PI showed the best correlation with measured ICP (R = 0.61). Considering every TCD recording as an independent event, nICP_BB generally showed to be the best estimator of measured ICP (R = 0.39; p < 0.05; 95% confidence interval [CI] = 9.94 mm Hg; area under the curve [AUC] = 0.66; p < 0.05). For nICP_FVd, although it presented similar correlation coefficient to nICP_BB and marginally better AUC (0.70; p < 0.05), it demonstrated a greater 95% CI for prediction of ICP (14.62 mm Hg). nICP_CrCP presented a moderate correlation coefficient (R = 0.35; p < 0.05) and similar 95% CI to nICP_BB (9.19 mm Hg), but failed to distinguish between normal and raised ICP (AUC = 0.64; p > 0.05). nICP_PI was not related to measured ICP using any of the above statistical indicators. We also introduced a new estimator (nICP_Av) based on the average of three methods (nICP_BB, nICP_FVd, and nICP_CrCP), which overall presented improved statistical indicators (R = 0.47; p < 0.05; 95% CI = 9.17 mm Hg; AUC = 0.73; p < 0.05). nICP_PI appeared to reflect changes in ICP in time most accurately. nICP_BB was the best estimator for ICP ''as a number.'' nICP_Av demonstrated to improve the accuracy of measured ICP estimation.
Background: Cell population-based studies obscure potential phagosomal heterogeneity. Results: We used a dynamic assay to monitor superoxide production in single phagosomes and uncovered variability in NADPH oxidase activity. Conclusion:The heterogeneity is attributable to variations in local DAG accumulation, which is controlled by DAG kinases. Significance: Heterogeneity in phagosome responsiveness could enable the survival of a fraction of invading microorganisms.
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